Sync from Piper @316511779

PROTOBUF_SYNC_PIPER

CHANGES.txt

@@ -1,12 +1,42 @@
 Unreleased Changes
 
   C++:
+  * Removed deprecated unsafe arena string accessors
   * Enabled heterogeneous lookup for std::string keys in maps.
-  * Improved the randomness of map ordering.
+  * Removed implicit conversion from StringPiece to std::string
+  * Fix use-after-destroy bug when the Map is allocated in the arena.
+  * Improved the randomness of map ordering
+  * Added stack overflow protection for text format with unknown fields
+  * Use std::hash for proto maps to help with portability.
+  * Added more Windows macros to proto whitelist.
+  * Arena constructors for map entry messages are now marked "explicit"
+    (for regular messages they were already explicit).
 
   Python:
+  * Reject lowercase t for Timestamp json format. Fixes a conformance test.
   * Improved the error message when AttributeError is returned from __getattr__
     in EnumTypeWrapper.
+  * Json format will print full_name directly for extensions.
+
+  Java:
+  * Fixed a bug where setting optional proto3 enums with setFooValue() would
+    not mark the value as present.
+
+  C#:
+  * Dropped support for netstandard1.0 (replaced by support for netstandard1.1).
+    This was required to modernize the parsing stack to use the `Span<byte>`
+    type internally. (#7351)
+  * Add `ParseFrom(ReadOnlySequence<byte>)` method to enable GC friendly
+    parsing with reduced allocations and buffer copies. (#7351)
+  * Add `GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE` define to make
+    generated code compatible with old C# compilers (pre-roslyn compilers
+    from .NET framework and old versions of mono) that do not support
+    ref structs. (#7490)
+
+2020-06-01 version 3.12.3 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
+
+  Objective-C
+  * Tweak the union used for Extensions to support old generated code. #7573
 
 2020-05-26 version 3.12.2 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
 

Protobuf.podspec

@@ -5,7 +5,7 @@
 # dependent projects use the :git notation to refer to the library.
 Pod::Spec.new do |s|
   s.name     = 'Protobuf'
-  s.version  = '3.12.2'
+  s.version  = '3.12.3'
   s.summary  = 'Protocol Buffers v.3 runtime library for Objective-C.'
   s.homepage = 'https://github.com/protocolbuffers/protobuf'
   s.license  = '3-Clause BSD License'

conformance/failure_list_csharp.txt

@@ -1,4 +1,3 @@
 Recommended.Proto3.JsonInput.BytesFieldBase64Url.JsonOutput
 Recommended.Proto3.JsonInput.BytesFieldBase64Url.ProtobufOutput
-Required.Proto2.JsonInput.StoresDefaultPrimitive.Validator
 Recommended.Proto2.JsonInput.FieldNameExtension.Validator

conformance/failure_list_python.txt

@@ -1,30 +0,0 @@
-Recommended.Proto3.JsonInput.BytesFieldBase64Url.JsonOutput
-Recommended.Proto3.JsonInput.BytesFieldBase64Url.ProtobufOutput
-Recommended.Proto3.JsonInput.DoubleFieldInfinityNotQuoted
-Recommended.Proto3.JsonInput.DoubleFieldNanNotQuoted
-Recommended.Proto3.JsonInput.DoubleFieldNegativeInfinityNotQuoted
-Recommended.Proto3.JsonInput.FloatFieldInfinityNotQuoted
-Recommended.Proto3.JsonInput.FloatFieldNanNotQuoted
-Recommended.Proto3.JsonInput.FloatFieldNegativeInfinityNotQuoted
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.BOOL[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.BYTES[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.DOUBLE[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.ENUM[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.FIXED32[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.FIXED64[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.FLOAT[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.INT32[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.INT32[6].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.INT64[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.SFIXED32[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.SFIXED64[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.SINT32[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.SINT64[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.STRING[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.UINT32[0].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.UINT32[5].ProtobufOutput
-Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.UINT64[0].ProtobufOutput
-Required.Proto3.JsonInput.DoubleFieldTooSmall
-Required.Proto3.JsonInput.FloatFieldTooLarge
-Required.Proto3.JsonInput.FloatFieldTooSmall
-Required.Proto3.JsonInput.RepeatedFieldWrongElementTypeExpectingIntegersGotBool

conformance/failure_list_python_cpp.txt

@@ -6,16 +6,3 @@
 #
 # TODO(haberman): insert links to corresponding bugs tracking the issue.
 # Should we use GitHub issues or the Google-internal bug tracker?
-
-Recommended.Proto3.JsonInput.BytesFieldBase64Url.JsonOutput
-Recommended.Proto3.JsonInput.BytesFieldBase64Url.ProtobufOutput
-Recommended.Proto3.JsonInput.DoubleFieldInfinityNotQuoted
-Recommended.Proto3.JsonInput.DoubleFieldNanNotQuoted
-Recommended.Proto3.JsonInput.DoubleFieldNegativeInfinityNotQuoted
-Recommended.Proto3.JsonInput.FloatFieldInfinityNotQuoted
-Recommended.Proto3.JsonInput.FloatFieldNanNotQuoted
-Recommended.Proto3.JsonInput.FloatFieldNegativeInfinityNotQuoted
-Required.Proto3.JsonInput.DoubleFieldTooSmall
-Required.Proto3.JsonInput.FloatFieldTooLarge
-Required.Proto3.JsonInput.FloatFieldTooSmall
-Required.Proto3.JsonInput.RepeatedFieldWrongElementTypeExpectingIntegersGotBool

csharp/Google.Protobuf.Tools.nuspec

@@ -5,7 +5,7 @@
     <title>Google Protocol Buffers tools</title>
     <summary>Tools for Protocol Buffers - Google's data interchange format.</summary>
     <description>See project site for more info.</description>
-    <version>3.12.2</version>
+    <version>3.12.3</version>
     <authors>Google Inc.</authors>
     <owners>protobuf-packages</owners>
     <licenseUrl>https://github.com/protocolbuffers/protobuf/blob/master/LICENSE</licenseUrl>

csharp/src/AddressBook/Addressbook.cs

@@ -49,7 +49,11 @@ namespace Google.Protobuf.Examples.AddressBook {
   /// <summary>
   /// [START messages]
   /// </summary>
-  public sealed partial class Person : pb::IMessage<Person>, pb::IBufferMessage {
+  public sealed partial class Person : pb::IMessage<Person>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Person> _parser = new pb::MessageParser<Person>(() => new Person());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -256,9 +260,44 @@ namespace Google.Protobuf.Examples.AddressBook {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 16: {
+            Id = input.ReadInt32();
+            break;
+          }
+          case 26: {
+            Email = input.ReadString();
+            break;
+          }
+          case 34: {
+            phones_.AddEntriesFrom(input, _repeated_phones_codec);
+            break;
+          }
+          case 42: {
+            if (lastUpdated_ == null) {
+              LastUpdated = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+            }
+            input.ReadMessage(LastUpdated);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -293,6 +332,7 @@ namespace Google.Protobuf.Examples.AddressBook {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the Person message type.</summary>
@@ -304,7 +344,11 @@ namespace Google.Protobuf.Examples.AddressBook {
         [pbr::OriginalName("WORK")] Work = 2,
       }
 
-      public sealed partial class PhoneNumber : pb::IMessage<PhoneNumber>, pb::IBufferMessage {
+      public sealed partial class PhoneNumber : pb::IMessage<PhoneNumber>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<PhoneNumber> _parser = new pb::MessageParser<PhoneNumber>(() => new PhoneNumber());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -441,9 +485,29 @@ namespace Google.Protobuf.Examples.AddressBook {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 10: {
+                Number = input.ReadString();
+                break;
+              }
+              case 16: {
+                Type = (global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType) input.ReadEnum();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -463,6 +527,7 @@ namespace Google.Protobuf.Examples.AddressBook {
             }
           }
         }
+        #endif
 
       }
 
@@ -474,7 +539,11 @@ namespace Google.Protobuf.Examples.AddressBook {
   /// <summary>
   /// Our address book file is just one of these.
   /// </summary>
-  public sealed partial class AddressBook : pb::IMessage<AddressBook>, pb::IBufferMessage {
+  public sealed partial class AddressBook : pb::IMessage<AddressBook>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<AddressBook> _parser = new pb::MessageParser<AddressBook>(() => new AddressBook());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -579,9 +648,25 @@ namespace Google.Protobuf.Examples.AddressBook {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            people_.AddEntriesFrom(input, _repeated_people_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -597,6 +682,7 @@ namespace Google.Protobuf.Examples.AddressBook {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Benchmarks/BenchmarkMessage1Proto3.cs

@@ -64,7 +64,11 @@ namespace Benchmarks.Proto3 {
 
   }
   #region Messages
-  public sealed partial class GoogleMessage1 : pb::IMessage<GoogleMessage1>, pb::IBufferMessage {
+  public sealed partial class GoogleMessage1 : pb::IMessage<GoogleMessage1>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<GoogleMessage1> _parser = new pb::MessageParser<GoogleMessage1>(() => new GoogleMessage1());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1132,9 +1136,189 @@ namespace Benchmarks.Proto3 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Field1 = input.ReadString();
+            break;
+          }
+          case 16: {
+            Field2 = input.ReadInt32();
+            break;
+          }
+          case 24: {
+            Field3 = input.ReadInt32();
+            break;
+          }
+          case 34: {
+            Field4 = input.ReadString();
+            break;
+          }
+          case 42:
+          case 41: {
+            field5_.AddEntriesFrom(input, _repeated_field5_codec);
+            break;
+          }
+          case 48: {
+            Field6 = input.ReadInt32();
+            break;
+          }
+          case 58: {
+            Field7 = input.ReadString();
+            break;
+          }
+          case 74: {
+            Field9 = input.ReadString();
+            break;
+          }
+          case 96: {
+            Field12 = input.ReadBool();
+            break;
+          }
+          case 104: {
+            Field13 = input.ReadBool();
+            break;
+          }
+          case 112: {
+            Field14 = input.ReadBool();
+            break;
+          }
+          case 122: {
+            if (field15_ == null) {
+              Field15 = new global::Benchmarks.Proto3.GoogleMessage1SubMessage();
+            }
+            input.ReadMessage(Field15);
+            break;
+          }
+          case 128: {
+            Field16 = input.ReadInt32();
+            break;
+          }
+          case 136: {
+            Field17 = input.ReadBool();
+            break;
+          }
+          case 146: {
+            Field18 = input.ReadString();
+            break;
+          }
+          case 176: {
+            Field22 = input.ReadInt64();
+            break;
+          }
+          case 184: {
+            Field23 = input.ReadInt32();
+            break;
+          }
+          case 192: {
+            Field24 = input.ReadBool();
+            break;
+          }
+          case 200: {
+            Field25 = input.ReadInt32();
+            break;
+          }
+          case 232: {
+            Field29 = input.ReadInt32();
+            break;
+          }
+          case 240: {
+            Field30 = input.ReadBool();
+            break;
+          }
+          case 472: {
+            Field59 = input.ReadBool();
+            break;
+          }
+          case 480: {
+            Field60 = input.ReadInt32();
+            break;
+          }
+          case 536: {
+            Field67 = input.ReadInt32();
+            break;
+          }
+          case 544: {
+            Field68 = input.ReadInt32();
+            break;
+          }
+          case 624: {
+            Field78 = input.ReadBool();
+            break;
+          }
+          case 640: {
+            Field80 = input.ReadBool();
+            break;
+          }
+          case 648: {
+            Field81 = input.ReadBool();
+            break;
+          }
+          case 800: {
+            Field100 = input.ReadInt32();
+            break;
+          }
+          case 808: {
+            Field101 = input.ReadInt32();
+            break;
+          }
+          case 818: {
+            Field102 = input.ReadString();
+            break;
+          }
+          case 826: {
+            Field103 = input.ReadString();
+            break;
+          }
+          case 832: {
+            Field104 = input.ReadInt32();
+            break;
+          }
+          case 1024: {
+            Field128 = input.ReadInt32();
+            break;
+          }
+          case 1034: {
+            Field129 = input.ReadString();
+            break;
+          }
+          case 1040: {
+            Field130 = input.ReadInt32();
+            break;
+          }
+          case 1048: {
+            Field131 = input.ReadInt32();
+            break;
+          }
+          case 1200: {
+            Field150 = input.ReadInt32();
+            break;
+          }
+          case 2168: {
+            Field271 = input.ReadInt32();
+            break;
+          }
+          case 2176: {
+            Field272 = input.ReadInt32();
+            break;
+          }
+          case 2240: {
+            Field280 = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1314,10 +1498,15 @@ namespace Benchmarks.Proto3 {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class GoogleMessage1SubMessage : pb::IMessage<GoogleMessage1SubMessage>, pb::IBufferMessage {
+  public sealed partial class GoogleMessage1SubMessage : pb::IMessage<GoogleMessage1SubMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<GoogleMessage1SubMessage> _parser = new pb::MessageParser<GoogleMessage1SubMessage>(() => new GoogleMessage1SubMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1886,9 +2075,101 @@ namespace Benchmarks.Proto3 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Field1 = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            Field2 = input.ReadInt32();
+            break;
+          }
+          case 24: {
+            Field3 = input.ReadInt32();
+            break;
+          }
+          case 96: {
+            Field12 = input.ReadBool();
+            break;
+          }
+          case 104: {
+            Field13 = input.ReadInt64();
+            break;
+          }
+          case 112: {
+            Field14 = input.ReadInt64();
+            break;
+          }
+          case 122: {
+            Field15 = input.ReadString();
+            break;
+          }
+          case 128: {
+            Field16 = input.ReadInt32();
+            break;
+          }
+          case 152: {
+            Field19 = input.ReadInt32();
+            break;
+          }
+          case 160: {
+            Field20 = input.ReadBool();
+            break;
+          }
+          case 169: {
+            Field21 = input.ReadFixed64();
+            break;
+          }
+          case 176: {
+            Field22 = input.ReadInt32();
+            break;
+          }
+          case 184: {
+            Field23 = input.ReadBool();
+            break;
+          }
+          case 224: {
+            Field28 = input.ReadBool();
+            break;
+          }
+          case 1629: {
+            Field203 = input.ReadFixed32();
+            break;
+          }
+          case 1632: {
+            Field204 = input.ReadInt32();
+            break;
+          }
+          case 1642: {
+            Field205 = input.ReadString();
+            break;
+          }
+          case 1648: {
+            Field206 = input.ReadBool();
+            break;
+          }
+          case 1656: {
+            Field207 = input.ReadUInt64();
+            break;
+          }
+          case 2400: {
+            Field300 = input.ReadUInt64();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1980,6 +2261,7 @@ namespace Benchmarks.Proto3 {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Benchmarks/Benchmarks.cs

@@ -38,7 +38,11 @@ namespace Benchmarks {
 
   }
   #region Messages
-  public sealed partial class BenchmarkDataset : pb::IMessage<BenchmarkDataset>, pb::IBufferMessage {
+  public sealed partial class BenchmarkDataset : pb::IMessage<BenchmarkDataset>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<BenchmarkDataset> _parser = new pb::MessageParser<BenchmarkDataset>(() => new BenchmarkDataset());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -219,9 +223,33 @@ namespace Benchmarks {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            MessageName = input.ReadString();
+            break;
+          }
+          case 26: {
+            payload_.AddEntriesFrom(input, _repeated_payload_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -245,6 +273,7 @@ namespace Benchmarks {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Benchmarks/ParseMessagesBenchmark.cs

@@ -37,6 +37,7 @@ using System.IO;
 using System.Linq;
 using System.Buffers;
 using Google.Protobuf.WellKnownTypes;
+using Benchmarks.Proto3;
 
 namespace Google.Protobuf.Benchmarks
 {
@@ -50,6 +51,7 @@ namespace Google.Protobuf.Benchmarks
 
         SubTest manyWrapperFieldsTest = new SubTest(CreateManyWrapperFieldsMessage(), ManyWrapperFieldsMessage.Parser, () => new ManyWrapperFieldsMessage(), MaxMessages);
         SubTest manyPrimitiveFieldsTest = new SubTest(CreateManyPrimitiveFieldsMessage(), ManyPrimitiveFieldsMessage.Parser, () => new ManyPrimitiveFieldsMessage(), MaxMessages);
+        SubTest repeatedFieldTest = new SubTest(CreateRepeatedFieldMessage(), GoogleMessage1.Parser, () => new GoogleMessage1(), MaxMessages);
         SubTest emptyMessageTest = new SubTest(new Empty(), Empty.Parser, () => new Empty(), MaxMessages);
 
         public IEnumerable<int> MessageCountValues => new[] { 10, 100 };
@@ -83,6 +85,18 @@ namespace Google.Protobuf.Benchmarks
             return manyPrimitiveFieldsTest.ParseFromReadOnlySequence();
         }
 
+        [Benchmark]
+        public IMessage RepeatedFieldMessage_ParseFromByteArray()
+        {
+            return repeatedFieldTest.ParseFromByteArray();
+        }
+
+        [Benchmark]
+        public IMessage RepeatedFieldMessage_ParseFromReadOnlySequence()
+        {
+            return repeatedFieldTest.ParseFromReadOnlySequence();
+        }
+
         [Benchmark]
         public IMessage EmptyMessage_ParseFromByteArray()
         {
@@ -123,6 +137,20 @@ namespace Google.Protobuf.Benchmarks
             manyPrimitiveFieldsTest.ParseDelimitedMessagesFromReadOnlySequence(messageCount);
         }
 
+        [Benchmark]
+        [ArgumentsSource(nameof(MessageCountValues))]
+        public void RepeatedFieldMessage_ParseDelimitedMessagesFromByteArray(int messageCount)
+        {
+            repeatedFieldTest.ParseDelimitedMessagesFromByteArray(messageCount);
+        }
+
+        [Benchmark]
+        [ArgumentsSource(nameof(MessageCountValues))]
+        public void RepeatedFieldMessage_ParseDelimitedMessagesFromReadOnlySequence(int messageCount)
+        {
+            repeatedFieldTest.ParseDelimitedMessagesFromReadOnlySequence(messageCount);
+        }
+
         private static ManyWrapperFieldsMessage CreateManyWrapperFieldsMessage()
         {
             // Example data match data of an internal benchmarks
@@ -157,6 +185,17 @@ namespace Google.Protobuf.Benchmarks
             };
         }
 
+        private static GoogleMessage1 CreateRepeatedFieldMessage()
+        {
+            // Message with a repeated fixed length item collection
+            var message = new GoogleMessage1();
+            for (ulong i = 0; i < 1000; i++)
+            {
+                message.Field5.Add(i);
+            }
+            return message;
+        }
+
         private class SubTest
         {
             private readonly IMessage message;

csharp/src/Google.Protobuf.Conformance/Conformance.cs

@@ -107,7 +107,11 @@ namespace Conformance {
   /// This will be known by message_type == "conformance.FailureSet", a conformance
   /// test should return a serialized FailureSet in protobuf_payload.
   /// </summary>
-  public sealed partial class FailureSet : pb::IMessage<FailureSet>, pb::IBufferMessage {
+  public sealed partial class FailureSet : pb::IMessage<FailureSet>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<FailureSet> _parser = new pb::MessageParser<FailureSet>(() => new FailureSet());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -212,9 +216,25 @@ namespace Conformance {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            failure_.AddEntriesFrom(input, _repeated_failure_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -230,6 +250,7 @@ namespace Conformance {
         }
       }
     }
+    #endif
 
   }
 
@@ -240,7 +261,11 @@ namespace Conformance {
   ///   2. parse the protobuf or JSON payload in "payload" (which may fail)
   ///   3. if the parse succeeded, serialize the message in the requested format.
   /// </summary>
-  public sealed partial class ConformanceRequest : pb::IMessage<ConformanceRequest>, pb::IBufferMessage {
+  public sealed partial class ConformanceRequest : pb::IMessage<ConformanceRequest>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ConformanceRequest> _parser = new pb::MessageParser<ConformanceRequest>(() => new ConformanceRequest());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -608,9 +633,60 @@ namespace Conformance {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            ProtobufPayload = input.ReadBytes();
+            break;
+          }
+          case 18: {
+            JsonPayload = input.ReadString();
+            break;
+          }
+          case 24: {
+            RequestedOutputFormat = (global::Conformance.WireFormat) input.ReadEnum();
+            break;
+          }
+          case 34: {
+            MessageType = input.ReadString();
+            break;
+          }
+          case 40: {
+            TestCategory = (global::Conformance.TestCategory) input.ReadEnum();
+            break;
+          }
+          case 50: {
+            if (jspbEncodingOptions_ == null) {
+              JspbEncodingOptions = new global::Conformance.JspbEncodingConfig();
+            }
+            input.ReadMessage(JspbEncodingOptions);
+            break;
+          }
+          case 58: {
+            JspbPayload = input.ReadString();
+            break;
+          }
+          case 66: {
+            TextPayload = input.ReadString();
+            break;
+          }
+          case 72: {
+            PrintUnknownFields = input.ReadBool();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -661,13 +737,18 @@ namespace Conformance {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Represents a single test case's output.
   /// </summary>
-  public sealed partial class ConformanceResponse : pb::IMessage<ConformanceResponse>, pb::IBufferMessage {
+  public sealed partial class ConformanceResponse : pb::IMessage<ConformanceResponse>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ConformanceResponse> _parser = new pb::MessageParser<ConformanceResponse>(() => new ConformanceResponse());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1035,9 +1116,53 @@ namespace Conformance {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            ParseError = input.ReadString();
+            break;
+          }
+          case 18: {
+            RuntimeError = input.ReadString();
+            break;
+          }
+          case 26: {
+            ProtobufPayload = input.ReadBytes();
+            break;
+          }
+          case 34: {
+            JsonPayload = input.ReadString();
+            break;
+          }
+          case 42: {
+            Skipped = input.ReadString();
+            break;
+          }
+          case 50: {
+            SerializeError = input.ReadString();
+            break;
+          }
+          case 58: {
+            JspbPayload = input.ReadString();
+            break;
+          }
+          case 66: {
+            TextPayload = input.ReadString();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1081,13 +1206,18 @@ namespace Conformance {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Encoding options for jspb format.
   /// </summary>
-  public sealed partial class JspbEncodingConfig : pb::IMessage<JspbEncodingConfig>, pb::IBufferMessage {
+  public sealed partial class JspbEncodingConfig : pb::IMessage<JspbEncodingConfig>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<JspbEncodingConfig> _parser = new pb::MessageParser<JspbEncodingConfig>(() => new JspbEncodingConfig());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1203,9 +1333,25 @@ namespace Conformance {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            UseJspbArrayAnyFormat = input.ReadBool();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1221,6 +1367,7 @@ namespace Conformance {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Conformance/Program.cs

@@ -83,44 +83,52 @@ namespace Google.Protobuf.Conformance
 
         private static ConformanceResponse PerformRequest(ConformanceRequest request, TypeRegistry typeRegistry)
         {
+            ExtensionRegistry proto2ExtensionRegistry = new ExtensionRegistry
+            {
+                ProtobufTestMessages.Proto2.TestMessagesProto2Extensions.ExtensionInt32,
+                ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.MessageSetCorrectExtension1.Extensions.MessageSetExtension,
+                ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.MessageSetCorrectExtension2.Extensions.MessageSetExtension
+            };
             IMessage message;
             try
             {
                 switch (request.PayloadCase)
                 {
                     case ConformanceRequest.PayloadOneofCase.JsonPayload:
-                        if (request.TestCategory == global::Conformance.TestCategory.JsonIgnoreUnknownParsingTest) {
+                        if (request.TestCategory == global::Conformance.TestCategory.JsonIgnoreUnknownParsingTest)
+                        {
                             return new ConformanceResponse { Skipped = "CSharp doesn't support skipping unknown fields in json parsing." };
                         }
                         var parser = new JsonParser(new JsonParser.Settings(20, typeRegistry));
-                        message = parser.Parse<ProtobufTestMessages.Proto3.TestAllTypesProto3>(request.JsonPayload);
-                        break;
-                    case ConformanceRequest.PayloadOneofCase.ProtobufPayload:
-                    {
-                        if (request.MessageType.Equals("protobuf_test_messages.proto3.TestAllTypesProto3"))
+                        switch (request.MessageType)
                         {
-                            message = ProtobufTestMessages.Proto3.TestAllTypesProto3.Parser.ParseFrom(request.ProtobufPayload);
+                            case "protobuf_test_messages.proto3.TestAllTypesProto3":
+                                message = parser.Parse<ProtobufTestMessages.Proto3.TestAllTypesProto3>(request.JsonPayload);
+                                break;
+                            case "protobuf_test_messages.proto2.TestAllTypesProto2":
+                                message = parser.Parse<ProtobufTestMessages.Proto2.TestAllTypesProto2>(request.JsonPayload);
+                                break;
+                            default:
+                                throw new Exception($" Protobuf request doesn't have specific payload type ({request.MessageType})");
                         }
-                        else if (request.MessageType.Equals("protobuf_test_messages.proto2.TestAllTypesProto2"))
-                        {
-                            ExtensionRegistry registry = new ExtensionRegistry()
-                            {
-                                ProtobufTestMessages.Proto2.TestMessagesProto2Extensions.ExtensionInt32,
-                                ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.MessageSetCorrectExtension1.Extensions.MessageSetExtension,
-                                ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.MessageSetCorrectExtension2.Extensions.MessageSetExtension
-                            };
-                            message = ProtobufTestMessages.Proto2.TestAllTypesProto2.Parser.WithExtensionRegistry(registry).ParseFrom(request.ProtobufPayload);
-                        }
-                        else
+                        break;
+                    case ConformanceRequest.PayloadOneofCase.ProtobufPayload:
+                        switch (request.MessageType)
                         {
-                            throw new Exception(" Protobuf request doesn't have specific payload type");
+                            case "protobuf_test_messages.proto3.TestAllTypesProto3":
+                                message = ProtobufTestMessages.Proto3.TestAllTypesProto3.Parser.ParseFrom(request.ProtobufPayload);
+                                break;
+                            case "protobuf_test_messages.proto2.TestAllTypesProto2":
+                                message = ProtobufTestMessages.Proto2.TestAllTypesProto2.Parser
+                                    .WithExtensionRegistry(proto2ExtensionRegistry)
+                                    .ParseFrom(request.ProtobufPayload);
+                                break;
+                            default:
+                                throw new Exception($" Protobuf request doesn't have specific payload type ({request.MessageType})");
                         }
                         break;
-                    }
 					case ConformanceRequest.PayloadOneofCase.TextPayload:
-					{
 						return new ConformanceResponse { Skipped = "CSharp doesn't support text format" };
-					}
                     default:
                         throw new Exception("Unsupported request payload: " + request.PayloadCase);
                 }

csharp/src/Google.Protobuf.Test.TestProtos/MapUnittestProto3.cs

@@ -176,7 +176,11 @@ namespace Google.Protobuf.TestProtos {
   /// <summary>
   /// Tests maps.
   /// </summary>
-  public sealed partial class TestMap : pb::IMessage<TestMap>, pb::IBufferMessage {
+  public sealed partial class TestMap : pb::IMessage<TestMap>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestMap> _parser = new pb::MessageParser<TestMap>(() => new TestMap());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -537,9 +541,89 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            mapInt32Int32_.AddEntriesFrom(input, _map_mapInt32Int32_codec);
+            break;
+          }
+          case 18: {
+            mapInt64Int64_.AddEntriesFrom(input, _map_mapInt64Int64_codec);
+            break;
+          }
+          case 26: {
+            mapUint32Uint32_.AddEntriesFrom(input, _map_mapUint32Uint32_codec);
+            break;
+          }
+          case 34: {
+            mapUint64Uint64_.AddEntriesFrom(input, _map_mapUint64Uint64_codec);
+            break;
+          }
+          case 42: {
+            mapSint32Sint32_.AddEntriesFrom(input, _map_mapSint32Sint32_codec);
+            break;
+          }
+          case 50: {
+            mapSint64Sint64_.AddEntriesFrom(input, _map_mapSint64Sint64_codec);
+            break;
+          }
+          case 58: {
+            mapFixed32Fixed32_.AddEntriesFrom(input, _map_mapFixed32Fixed32_codec);
+            break;
+          }
+          case 66: {
+            mapFixed64Fixed64_.AddEntriesFrom(input, _map_mapFixed64Fixed64_codec);
+            break;
+          }
+          case 74: {
+            mapSfixed32Sfixed32_.AddEntriesFrom(input, _map_mapSfixed32Sfixed32_codec);
+            break;
+          }
+          case 82: {
+            mapSfixed64Sfixed64_.AddEntriesFrom(input, _map_mapSfixed64Sfixed64_codec);
+            break;
+          }
+          case 90: {
+            mapInt32Float_.AddEntriesFrom(input, _map_mapInt32Float_codec);
+            break;
+          }
+          case 98: {
+            mapInt32Double_.AddEntriesFrom(input, _map_mapInt32Double_codec);
+            break;
+          }
+          case 106: {
+            mapBoolBool_.AddEntriesFrom(input, _map_mapBoolBool_codec);
+            break;
+          }
+          case 114: {
+            mapStringString_.AddEntriesFrom(input, _map_mapStringString_codec);
+            break;
+          }
+          case 122: {
+            mapInt32Bytes_.AddEntriesFrom(input, _map_mapInt32Bytes_codec);
+            break;
+          }
+          case 130: {
+            mapInt32Enum_.AddEntriesFrom(input, _map_mapInt32Enum_codec);
+            break;
+          }
+          case 138: {
+            mapInt32ForeignMessage_.AddEntriesFrom(input, _map_mapInt32ForeignMessage_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -619,10 +703,15 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class TestMapSubmessage : pb::IMessage<TestMapSubmessage>, pb::IBufferMessage {
+  public sealed partial class TestMapSubmessage : pb::IMessage<TestMapSubmessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestMapSubmessage> _parser = new pb::MessageParser<TestMapSubmessage>(() => new TestMapSubmessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -738,9 +827,28 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            if (testMap_ == null) {
+              TestMap = new global::Google.Protobuf.TestProtos.TestMap();
+            }
+            input.ReadMessage(TestMap);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -759,10 +867,15 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class TestMessageMap : pb::IMessage<TestMessageMap>, pb::IBufferMessage {
+  public sealed partial class TestMessageMap : pb::IMessage<TestMessageMap>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestMessageMap> _parser = new pb::MessageParser<TestMessageMap>(() => new TestMessageMap());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -867,9 +980,25 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            mapInt32Message_.AddEntriesFrom(input, _map_mapInt32Message_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -885,13 +1014,18 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Two map fields share the same entry default instance.
   /// </summary>
-  public sealed partial class TestSameTypeMap : pb::IMessage<TestSameTypeMap>, pb::IBufferMessage {
+  public sealed partial class TestSameTypeMap : pb::IMessage<TestSameTypeMap>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestSameTypeMap> _parser = new pb::MessageParser<TestSameTypeMap>(() => new TestSameTypeMap());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1012,9 +1146,29 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            map1_.AddEntriesFrom(input, _map_map1_codec);
+            break;
+          }
+          case 18: {
+            map2_.AddEntriesFrom(input, _map_map2_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1034,10 +1188,15 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class TestArenaMap : pb::IMessage<TestArenaMap>, pb::IBufferMessage {
+  public sealed partial class TestArenaMap : pb::IMessage<TestArenaMap>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestArenaMap> _parser = new pb::MessageParser<TestArenaMap>(() => new TestArenaMap());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1366,9 +1525,81 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            mapInt32Int32_.AddEntriesFrom(input, _map_mapInt32Int32_codec);
+            break;
+          }
+          case 18: {
+            mapInt64Int64_.AddEntriesFrom(input, _map_mapInt64Int64_codec);
+            break;
+          }
+          case 26: {
+            mapUint32Uint32_.AddEntriesFrom(input, _map_mapUint32Uint32_codec);
+            break;
+          }
+          case 34: {
+            mapUint64Uint64_.AddEntriesFrom(input, _map_mapUint64Uint64_codec);
+            break;
+          }
+          case 42: {
+            mapSint32Sint32_.AddEntriesFrom(input, _map_mapSint32Sint32_codec);
+            break;
+          }
+          case 50: {
+            mapSint64Sint64_.AddEntriesFrom(input, _map_mapSint64Sint64_codec);
+            break;
+          }
+          case 58: {
+            mapFixed32Fixed32_.AddEntriesFrom(input, _map_mapFixed32Fixed32_codec);
+            break;
+          }
+          case 66: {
+            mapFixed64Fixed64_.AddEntriesFrom(input, _map_mapFixed64Fixed64_codec);
+            break;
+          }
+          case 74: {
+            mapSfixed32Sfixed32_.AddEntriesFrom(input, _map_mapSfixed32Sfixed32_codec);
+            break;
+          }
+          case 82: {
+            mapSfixed64Sfixed64_.AddEntriesFrom(input, _map_mapSfixed64Sfixed64_codec);
+            break;
+          }
+          case 90: {
+            mapInt32Float_.AddEntriesFrom(input, _map_mapInt32Float_codec);
+            break;
+          }
+          case 98: {
+            mapInt32Double_.AddEntriesFrom(input, _map_mapInt32Double_codec);
+            break;
+          }
+          case 106: {
+            mapBoolBool_.AddEntriesFrom(input, _map_mapBoolBool_codec);
+            break;
+          }
+          case 114: {
+            mapInt32Enum_.AddEntriesFrom(input, _map_mapInt32Enum_codec);
+            break;
+          }
+          case 122: {
+            mapInt32ForeignMessage_.AddEntriesFrom(input, _map_mapInt32ForeignMessage_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1440,6 +1671,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
@@ -1447,7 +1679,11 @@ namespace Google.Protobuf.TestProtos {
   /// Previously, message containing enum called Type cannot be used as value of
   /// map field.
   /// </summary>
-  public sealed partial class MessageContainingEnumCalledType : pb::IMessage<MessageContainingEnumCalledType>, pb::IBufferMessage {
+  public sealed partial class MessageContainingEnumCalledType : pb::IMessage<MessageContainingEnumCalledType>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<MessageContainingEnumCalledType> _parser = new pb::MessageParser<MessageContainingEnumCalledType>(() => new MessageContainingEnumCalledType());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1552,9 +1788,25 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            type_.AddEntriesFrom(input, _map_type_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1570,6 +1822,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the MessageContainingEnumCalledType message type.</summary>
@@ -1587,7 +1840,11 @@ namespace Google.Protobuf.TestProtos {
   /// <summary>
   /// Previously, message cannot contain map field called "entry".
   /// </summary>
-  public sealed partial class MessageContainingMapCalledEntry : pb::IMessage<MessageContainingMapCalledEntry>, pb::IBufferMessage {
+  public sealed partial class MessageContainingMapCalledEntry : pb::IMessage<MessageContainingMapCalledEntry>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<MessageContainingMapCalledEntry> _parser = new pb::MessageParser<MessageContainingMapCalledEntry>(() => new MessageContainingMapCalledEntry());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1692,9 +1949,25 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            entry_.AddEntriesFrom(input, _map_entry_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1710,6 +1983,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/TestMessagesProto2.cs

@@ -244,7 +244,11 @@ namespace ProtobufTestMessages.Proto2 {
   /// could trigger bugs that occur in any message type in this file.  We verify
   /// this stays true in a unit test.
   /// </summary>
-  public sealed partial class TestAllTypesProto2 : pb::IExtendableMessage<TestAllTypesProto2>, pb::IBufferMessage {
+  public sealed partial class TestAllTypesProto2 : pb::IExtendableMessage<TestAllTypesProto2>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestAllTypesProto2> _parser = new pb::MessageParser<TestAllTypesProto2>(() => new TestAllTypesProto2());
     private pb::UnknownFieldSet _unknownFields;
     private pb::ExtensionSet<TestAllTypesProto2> _extensions;
@@ -3311,9 +3315,556 @@ namespace ProtobufTestMessages.Proto2 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            if (!pb::ExtensionSet.TryMergeFieldFrom(ref _extensions, input)) {
+              _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            }
+            break;
+          case 8: {
+            OptionalInt32 = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            OptionalInt64 = input.ReadInt64();
+            break;
+          }
+          case 24: {
+            OptionalUint32 = input.ReadUInt32();
+            break;
+          }
+          case 32: {
+            OptionalUint64 = input.ReadUInt64();
+            break;
+          }
+          case 40: {
+            OptionalSint32 = input.ReadSInt32();
+            break;
+          }
+          case 48: {
+            OptionalSint64 = input.ReadSInt64();
+            break;
+          }
+          case 61: {
+            OptionalFixed32 = input.ReadFixed32();
+            break;
+          }
+          case 65: {
+            OptionalFixed64 = input.ReadFixed64();
+            break;
+          }
+          case 77: {
+            OptionalSfixed32 = input.ReadSFixed32();
+            break;
+          }
+          case 81: {
+            OptionalSfixed64 = input.ReadSFixed64();
+            break;
+          }
+          case 93: {
+            OptionalFloat = input.ReadFloat();
+            break;
+          }
+          case 97: {
+            OptionalDouble = input.ReadDouble();
+            break;
+          }
+          case 104: {
+            OptionalBool = input.ReadBool();
+            break;
+          }
+          case 114: {
+            OptionalString = input.ReadString();
+            break;
+          }
+          case 122: {
+            OptionalBytes = input.ReadBytes();
+            break;
+          }
+          case 146: {
+            if (optionalNestedMessage_ == null) {
+              OptionalNestedMessage = new global::ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.NestedMessage();
+            }
+            input.ReadMessage(OptionalNestedMessage);
+            break;
+          }
+          case 154: {
+            if (optionalForeignMessage_ == null) {
+              OptionalForeignMessage = new global::ProtobufTestMessages.Proto2.ForeignMessageProto2();
+            }
+            input.ReadMessage(OptionalForeignMessage);
+            break;
+          }
+          case 168: {
+            OptionalNestedEnum = (global::ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.NestedEnum) input.ReadEnum();
+            break;
+          }
+          case 176: {
+            OptionalForeignEnum = (global::ProtobufTestMessages.Proto2.ForeignEnumProto2) input.ReadEnum();
+            break;
+          }
+          case 194: {
+            OptionalStringPiece = input.ReadString();
+            break;
+          }
+          case 202: {
+            OptionalCord = input.ReadString();
+            break;
+          }
+          case 218: {
+            if (recursiveMessage_ == null) {
+              RecursiveMessage = new global::ProtobufTestMessages.Proto2.TestAllTypesProto2();
+            }
+            input.ReadMessage(RecursiveMessage);
+            break;
+          }
+          case 250:
+          case 248: {
+            repeatedInt32_.AddEntriesFrom(input, _repeated_repeatedInt32_codec);
+            break;
+          }
+          case 258:
+          case 256: {
+            repeatedInt64_.AddEntriesFrom(input, _repeated_repeatedInt64_codec);
+            break;
+          }
+          case 266:
+          case 264: {
+            repeatedUint32_.AddEntriesFrom(input, _repeated_repeatedUint32_codec);
+            break;
+          }
+          case 274:
+          case 272: {
+            repeatedUint64_.AddEntriesFrom(input, _repeated_repeatedUint64_codec);
+            break;
+          }
+          case 282:
+          case 280: {
+            repeatedSint32_.AddEntriesFrom(input, _repeated_repeatedSint32_codec);
+            break;
+          }
+          case 290:
+          case 288: {
+            repeatedSint64_.AddEntriesFrom(input, _repeated_repeatedSint64_codec);
+            break;
+          }
+          case 298:
+          case 301: {
+            repeatedFixed32_.AddEntriesFrom(input, _repeated_repeatedFixed32_codec);
+            break;
+          }
+          case 306:
+          case 305: {
+            repeatedFixed64_.AddEntriesFrom(input, _repeated_repeatedFixed64_codec);
+            break;
+          }
+          case 314:
+          case 317: {
+            repeatedSfixed32_.AddEntriesFrom(input, _repeated_repeatedSfixed32_codec);
+            break;
+          }
+          case 322:
+          case 321: {
+            repeatedSfixed64_.AddEntriesFrom(input, _repeated_repeatedSfixed64_codec);
+            break;
+          }
+          case 330:
+          case 333: {
+            repeatedFloat_.AddEntriesFrom(input, _repeated_repeatedFloat_codec);
+            break;
+          }
+          case 338:
+          case 337: {
+            repeatedDouble_.AddEntriesFrom(input, _repeated_repeatedDouble_codec);
+            break;
+          }
+          case 346:
+          case 344: {
+            repeatedBool_.AddEntriesFrom(input, _repeated_repeatedBool_codec);
+            break;
+          }
+          case 354: {
+            repeatedString_.AddEntriesFrom(input, _repeated_repeatedString_codec);
+            break;
+          }
+          case 362: {
+            repeatedBytes_.AddEntriesFrom(input, _repeated_repeatedBytes_codec);
+            break;
+          }
+          case 386: {
+            repeatedNestedMessage_.AddEntriesFrom(input, _repeated_repeatedNestedMessage_codec);
+            break;
+          }
+          case 394: {
+            repeatedForeignMessage_.AddEntriesFrom(input, _repeated_repeatedForeignMessage_codec);
+            break;
+          }
+          case 410:
+          case 408: {
+            repeatedNestedEnum_.AddEntriesFrom(input, _repeated_repeatedNestedEnum_codec);
+            break;
+          }
+          case 418:
+          case 416: {
+            repeatedForeignEnum_.AddEntriesFrom(input, _repeated_repeatedForeignEnum_codec);
+            break;
+          }
+          case 434: {
+            repeatedStringPiece_.AddEntriesFrom(input, _repeated_repeatedStringPiece_codec);
+            break;
+          }
+          case 442: {
+            repeatedCord_.AddEntriesFrom(input, _repeated_repeatedCord_codec);
+            break;
+          }
+          case 450: {
+            mapInt32Int32_.AddEntriesFrom(input, _map_mapInt32Int32_codec);
+            break;
+          }
+          case 458: {
+            mapInt64Int64_.AddEntriesFrom(input, _map_mapInt64Int64_codec);
+            break;
+          }
+          case 466: {
+            mapUint32Uint32_.AddEntriesFrom(input, _map_mapUint32Uint32_codec);
+            break;
+          }
+          case 474: {
+            mapUint64Uint64_.AddEntriesFrom(input, _map_mapUint64Uint64_codec);
+            break;
+          }
+          case 482: {
+            mapSint32Sint32_.AddEntriesFrom(input, _map_mapSint32Sint32_codec);
+            break;
+          }
+          case 490: {
+            mapSint64Sint64_.AddEntriesFrom(input, _map_mapSint64Sint64_codec);
+            break;
+          }
+          case 498: {
+            mapFixed32Fixed32_.AddEntriesFrom(input, _map_mapFixed32Fixed32_codec);
+            break;
+          }
+          case 506: {
+            mapFixed64Fixed64_.AddEntriesFrom(input, _map_mapFixed64Fixed64_codec);
+            break;
+          }
+          case 514: {
+            mapSfixed32Sfixed32_.AddEntriesFrom(input, _map_mapSfixed32Sfixed32_codec);
+            break;
+          }
+          case 522: {
+            mapSfixed64Sfixed64_.AddEntriesFrom(input, _map_mapSfixed64Sfixed64_codec);
+            break;
+          }
+          case 530: {
+            mapInt32Float_.AddEntriesFrom(input, _map_mapInt32Float_codec);
+            break;
+          }
+          case 538: {
+            mapInt32Double_.AddEntriesFrom(input, _map_mapInt32Double_codec);
+            break;
+          }
+          case 546: {
+            mapBoolBool_.AddEntriesFrom(input, _map_mapBoolBool_codec);
+            break;
+          }
+          case 554: {
+            mapStringString_.AddEntriesFrom(input, _map_mapStringString_codec);
+            break;
+          }
+          case 562: {
+            mapStringBytes_.AddEntriesFrom(input, _map_mapStringBytes_codec);
+            break;
+          }
+          case 570: {
+            mapStringNestedMessage_.AddEntriesFrom(input, _map_mapStringNestedMessage_codec);
+            break;
+          }
+          case 578: {
+            mapStringForeignMessage_.AddEntriesFrom(input, _map_mapStringForeignMessage_codec);
+            break;
+          }
+          case 586: {
+            mapStringNestedEnum_.AddEntriesFrom(input, _map_mapStringNestedEnum_codec);
+            break;
+          }
+          case 594: {
+            mapStringForeignEnum_.AddEntriesFrom(input, _map_mapStringForeignEnum_codec);
+            break;
+          }
+          case 602:
+          case 600: {
+            packedInt32_.AddEntriesFrom(input, _repeated_packedInt32_codec);
+            break;
+          }
+          case 610:
+          case 608: {
+            packedInt64_.AddEntriesFrom(input, _repeated_packedInt64_codec);
+            break;
+          }
+          case 618:
+          case 616: {
+            packedUint32_.AddEntriesFrom(input, _repeated_packedUint32_codec);
+            break;
+          }
+          case 626:
+          case 624: {
+            packedUint64_.AddEntriesFrom(input, _repeated_packedUint64_codec);
+            break;
+          }
+          case 634:
+          case 632: {
+            packedSint32_.AddEntriesFrom(input, _repeated_packedSint32_codec);
+            break;
+          }
+          case 642:
+          case 640: {
+            packedSint64_.AddEntriesFrom(input, _repeated_packedSint64_codec);
+            break;
+          }
+          case 650:
+          case 653: {
+            packedFixed32_.AddEntriesFrom(input, _repeated_packedFixed32_codec);
+            break;
+          }
+          case 658:
+          case 657: {
+            packedFixed64_.AddEntriesFrom(input, _repeated_packedFixed64_codec);
+            break;
+          }
+          case 666:
+          case 669: {
+            packedSfixed32_.AddEntriesFrom(input, _repeated_packedSfixed32_codec);
+            break;
+          }
+          case 674:
+          case 673: {
+            packedSfixed64_.AddEntriesFrom(input, _repeated_packedSfixed64_codec);
+            break;
+          }
+          case 682:
+          case 685: {
+            packedFloat_.AddEntriesFrom(input, _repeated_packedFloat_codec);
+            break;
+          }
+          case 690:
+          case 689: {
+            packedDouble_.AddEntriesFrom(input, _repeated_packedDouble_codec);
+            break;
+          }
+          case 698:
+          case 696: {
+            packedBool_.AddEntriesFrom(input, _repeated_packedBool_codec);
+            break;
+          }
+          case 706:
+          case 704: {
+            packedNestedEnum_.AddEntriesFrom(input, _repeated_packedNestedEnum_codec);
+            break;
+          }
+          case 714:
+          case 712: {
+            unpackedInt32_.AddEntriesFrom(input, _repeated_unpackedInt32_codec);
+            break;
+          }
+          case 722:
+          case 720: {
+            unpackedInt64_.AddEntriesFrom(input, _repeated_unpackedInt64_codec);
+            break;
+          }
+          case 730:
+          case 728: {
+            unpackedUint32_.AddEntriesFrom(input, _repeated_unpackedUint32_codec);
+            break;
+          }
+          case 738:
+          case 736: {
+            unpackedUint64_.AddEntriesFrom(input, _repeated_unpackedUint64_codec);
+            break;
+          }
+          case 746:
+          case 744: {
+            unpackedSint32_.AddEntriesFrom(input, _repeated_unpackedSint32_codec);
+            break;
+          }
+          case 754:
+          case 752: {
+            unpackedSint64_.AddEntriesFrom(input, _repeated_unpackedSint64_codec);
+            break;
+          }
+          case 762:
+          case 765: {
+            unpackedFixed32_.AddEntriesFrom(input, _repeated_unpackedFixed32_codec);
+            break;
+          }
+          case 770:
+          case 769: {
+            unpackedFixed64_.AddEntriesFrom(input, _repeated_unpackedFixed64_codec);
+            break;
+          }
+          case 778:
+          case 781: {
+            unpackedSfixed32_.AddEntriesFrom(input, _repeated_unpackedSfixed32_codec);
+            break;
+          }
+          case 786:
+          case 785: {
+            unpackedSfixed64_.AddEntriesFrom(input, _repeated_unpackedSfixed64_codec);
+            break;
+          }
+          case 794:
+          case 797: {
+            unpackedFloat_.AddEntriesFrom(input, _repeated_unpackedFloat_codec);
+            break;
+          }
+          case 802:
+          case 801: {
+            unpackedDouble_.AddEntriesFrom(input, _repeated_unpackedDouble_codec);
+            break;
+          }
+          case 810:
+          case 808: {
+            unpackedBool_.AddEntriesFrom(input, _repeated_unpackedBool_codec);
+            break;
+          }
+          case 818:
+          case 816: {
+            unpackedNestedEnum_.AddEntriesFrom(input, _repeated_unpackedNestedEnum_codec);
+            break;
+          }
+          case 888: {
+            OneofUint32 = input.ReadUInt32();
+            break;
+          }
+          case 898: {
+            global::ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.NestedMessage subBuilder = new global::ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.NestedMessage();
+            if (oneofFieldCase_ == OneofFieldOneofCase.OneofNestedMessage) {
+              subBuilder.MergeFrom(OneofNestedMessage);
+            }
+            input.ReadMessage(subBuilder);
+            OneofNestedMessage = subBuilder;
+            break;
+          }
+          case 906: {
+            OneofString = input.ReadString();
+            break;
+          }
+          case 914: {
+            OneofBytes = input.ReadBytes();
+            break;
+          }
+          case 920: {
+            OneofBool = input.ReadBool();
+            break;
+          }
+          case 928: {
+            OneofUint64 = input.ReadUInt64();
+            break;
+          }
+          case 941: {
+            OneofFloat = input.ReadFloat();
+            break;
+          }
+          case 945: {
+            OneofDouble = input.ReadDouble();
+            break;
+          }
+          case 952: {
+            oneofField_ = input.ReadEnum();
+            oneofFieldCase_ = OneofFieldOneofCase.OneofEnum;
+            break;
+          }
+          case 1611: {
+            if (!HasData) {
+              Data = new global::ProtobufTestMessages.Proto2.TestAllTypesProto2.Types.Data();
+            }
+            input.ReadGroup(Data);
+            break;
+          }
+          case 3208: {
+            Fieldname1 = input.ReadInt32();
+            break;
+          }
+          case 3216: {
+            FieldName2 = input.ReadInt32();
+            break;
+          }
+          case 3224: {
+            FieldName3 = input.ReadInt32();
+            break;
+          }
+          case 3232: {
+            FieldName4 = input.ReadInt32();
+            break;
+          }
+          case 3240: {
+            Field0Name5 = input.ReadInt32();
+            break;
+          }
+          case 3248: {
+            Field0Name6 = input.ReadInt32();
+            break;
+          }
+          case 3256: {
+            FieldName7 = input.ReadInt32();
+            break;
+          }
+          case 3264: {
+            FieldName8 = input.ReadInt32();
+            break;
+          }
+          case 3272: {
+            FieldName9 = input.ReadInt32();
+            break;
+          }
+          case 3280: {
+            FieldName10 = input.ReadInt32();
+            break;
+          }
+          case 3288: {
+            FIELDNAME11 = input.ReadInt32();
+            break;
+          }
+          case 3296: {
+            FIELDName12 = input.ReadInt32();
+            break;
+          }
+          case 3304: {
+            FieldName13 = input.ReadInt32();
+            break;
+          }
+          case 3312: {
+            FieldName14 = input.ReadInt32();
+            break;
+          }
+          case 3320: {
+            FieldName15 = input.ReadInt32();
+            break;
+          }
+          case 3328: {
+            FieldName16 = input.ReadInt32();
+            break;
+          }
+          case 3336: {
+            FieldName17 = input.ReadInt32();
+            break;
+          }
+          case 3344: {
+            FieldName18 = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -3860,6 +4411,7 @@ namespace ProtobufTestMessages.Proto2 {
         }
       }
     }
+    #endif
 
     public TValue GetExtension<TValue>(pb::Extension<TestAllTypesProto2, TValue> extension) {
       return pb::ExtensionSet.Get(ref _extensions, extension);
@@ -3897,7 +4449,11 @@ namespace ProtobufTestMessages.Proto2 {
         [pbr::OriginalName("NEG")] Neg = -1,
       }
 
-      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>, pb::IBufferMessage {
+      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<NestedMessage> _parser = new pb::MessageParser<NestedMessage>(() => new NestedMessage());
         private pb::UnknownFieldSet _unknownFields;
         private int _hasBits0;
@@ -4052,9 +4608,32 @@ namespace ProtobufTestMessages.Proto2 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                A = input.ReadInt32();
+                break;
+              }
+              case 18: {
+                if (corecursive_ == null) {
+                  Corecursive = new global::ProtobufTestMessages.Proto2.TestAllTypesProto2();
+                }
+                input.ReadMessage(Corecursive);
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -4077,13 +4656,18 @@ namespace ProtobufTestMessages.Proto2 {
             }
           }
         }
+        #endif
 
       }
 
       /// <summary>
       /// groups
       /// </summary>
-      public sealed partial class Data : pb::IMessage<Data>, pb::IBufferMessage {
+      public sealed partial class Data : pb::IMessage<Data>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<Data> _parser = new pb::MessageParser<Data>(() => new Data());
         private pb::UnknownFieldSet _unknownFields;
         private int _hasBits0;
@@ -4248,9 +4832,31 @@ namespace ProtobufTestMessages.Proto2 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              case 1612:
+                return;
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 1616: {
+                GroupInt32 = input.ReadInt32();
+                break;
+              }
+              case 1624: {
+                GroupUint32 = input.ReadUInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -4272,13 +4878,18 @@ namespace ProtobufTestMessages.Proto2 {
             }
           }
         }
+        #endif
 
       }
 
       /// <summary>
       /// message_set test case.
       /// </summary>
-      public sealed partial class MessageSetCorrect : pb::IExtendableMessage<MessageSetCorrect>, pb::IBufferMessage {
+      public sealed partial class MessageSetCorrect : pb::IExtendableMessage<MessageSetCorrect>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<MessageSetCorrect> _parser = new pb::MessageParser<MessageSetCorrect>(() => new MessageSetCorrect());
         private pb::UnknownFieldSet _unknownFields;
         private pb::ExtensionSet<MessageSetCorrect> _extensions;
@@ -4383,9 +4994,23 @@ namespace ProtobufTestMessages.Proto2 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                if (!pb::ExtensionSet.TryMergeFieldFrom(ref _extensions, input)) {
+                  _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                }
+                break;
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -4399,6 +5024,7 @@ namespace ProtobufTestMessages.Proto2 {
             }
           }
         }
+        #endif
 
         public TValue GetExtension<TValue>(pb::Extension<MessageSetCorrect, TValue> extension) {
           return pb::ExtensionSet.Get(ref _extensions, extension);
@@ -4424,7 +5050,11 @@ namespace ProtobufTestMessages.Proto2 {
 
       }
 
-      public sealed partial class MessageSetCorrectExtension1 : pb::IMessage<MessageSetCorrectExtension1>, pb::IBufferMessage {
+      public sealed partial class MessageSetCorrectExtension1 : pb::IMessage<MessageSetCorrectExtension1>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<MessageSetCorrectExtension1> _parser = new pb::MessageParser<MessageSetCorrectExtension1>(() => new MessageSetCorrectExtension1());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -4549,9 +5179,25 @@ namespace ProtobufTestMessages.Proto2 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 202: {
+                Str = input.ReadString();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -4567,6 +5213,7 @@ namespace ProtobufTestMessages.Proto2 {
             }
           }
         }
+        #endif
 
         #region Extensions
         /// <summary>Container for extensions for other messages declared in the MessageSetCorrectExtension1 message type.</summary>
@@ -4579,7 +5226,11 @@ namespace ProtobufTestMessages.Proto2 {
 
       }
 
-      public sealed partial class MessageSetCorrectExtension2 : pb::IMessage<MessageSetCorrectExtension2>, pb::IBufferMessage {
+      public sealed partial class MessageSetCorrectExtension2 : pb::IMessage<MessageSetCorrectExtension2>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<MessageSetCorrectExtension2> _parser = new pb::MessageParser<MessageSetCorrectExtension2>(() => new MessageSetCorrectExtension2());
         private pb::UnknownFieldSet _unknownFields;
         private int _hasBits0;
@@ -4707,9 +5358,25 @@ namespace ProtobufTestMessages.Proto2 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 72: {
+                I = input.ReadInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -4725,6 +5392,7 @@ namespace ProtobufTestMessages.Proto2 {
             }
           }
         }
+        #endif
 
         #region Extensions
         /// <summary>Container for extensions for other messages declared in the MessageSetCorrectExtension2 message type.</summary>
@@ -4742,7 +5410,11 @@ namespace ProtobufTestMessages.Proto2 {
 
   }
 
-  public sealed partial class ForeignMessageProto2 : pb::IMessage<ForeignMessageProto2>, pb::IBufferMessage {
+  public sealed partial class ForeignMessageProto2 : pb::IMessage<ForeignMessageProto2>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ForeignMessageProto2> _parser = new pb::MessageParser<ForeignMessageProto2>(() => new ForeignMessageProto2());
     private pb::UnknownFieldSet _unknownFields;
     private int _hasBits0;
@@ -4870,9 +5542,25 @@ namespace ProtobufTestMessages.Proto2 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            C = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -4888,10 +5576,15 @@ namespace ProtobufTestMessages.Proto2 {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class UnknownToTestAllTypes : pb::IMessage<UnknownToTestAllTypes>, pb::IBufferMessage {
+  public sealed partial class UnknownToTestAllTypes : pb::IMessage<UnknownToTestAllTypes>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<UnknownToTestAllTypes> _parser = new pb::MessageParser<UnknownToTestAllTypes>(() => new UnknownToTestAllTypes());
     private pb::UnknownFieldSet _unknownFields;
     private int _hasBits0;
@@ -5173,9 +5866,52 @@ namespace ProtobufTestMessages.Proto2 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8008: {
+            OptionalInt32 = input.ReadInt32();
+            break;
+          }
+          case 8018: {
+            OptionalString = input.ReadString();
+            break;
+          }
+          case 8026: {
+            if (nestedMessage_ == null) {
+              NestedMessage = new global::ProtobufTestMessages.Proto2.ForeignMessageProto2();
+            }
+            input.ReadMessage(NestedMessage);
+            break;
+          }
+          case 8035: {
+            if (!HasOptionalGroup) {
+              OptionalGroup = new global::ProtobufTestMessages.Proto2.UnknownToTestAllTypes.Types.OptionalGroup();
+            }
+            input.ReadGroup(OptionalGroup);
+            break;
+          }
+          case 8048: {
+            OptionalBool = input.ReadBool();
+            break;
+          }
+          case 8090:
+          case 8088: {
+            repeatedInt32_.AddEntriesFrom(input, _repeated_repeatedInt32_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -5218,12 +5954,17 @@ namespace ProtobufTestMessages.Proto2 {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the UnknownToTestAllTypes message type.</summary>
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public static partial class Types {
-      public sealed partial class OptionalGroup : pb::IMessage<OptionalGroup>, pb::IBufferMessage {
+      public sealed partial class OptionalGroup : pb::IMessage<OptionalGroup>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<OptionalGroup> _parser = new pb::MessageParser<OptionalGroup>(() => new OptionalGroup());
         private pb::UnknownFieldSet _unknownFields;
         private int _hasBits0;
@@ -5351,9 +6092,27 @@ namespace ProtobufTestMessages.Proto2 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              case 8036:
+                return;
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                A = input.ReadInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -5371,6 +6130,7 @@ namespace ProtobufTestMessages.Proto2 {
             }
           }
         }
+        #endif
 
       }
 

csharp/src/Google.Protobuf.Test.TestProtos/TestMessagesProto3.cs

@@ -259,7 +259,11 @@ namespace ProtobufTestMessages.Proto3 {
   /// could trigger bugs that occur in any message type in this file.  We verify
   /// this stays true in a unit test.
   /// </summary>
-  public sealed partial class TestAllTypesProto3 : pb::IMessage<TestAllTypesProto3>, pb::IBufferMessage {
+  public sealed partial class TestAllTypesProto3 : pb::IMessage<TestAllTypesProto3>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestAllTypesProto3> _parser = new pb::MessageParser<TestAllTypesProto3>(() => new TestAllTypesProto3());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -3383,9 +3387,720 @@ namespace ProtobufTestMessages.Proto3 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            OptionalInt32 = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            OptionalInt64 = input.ReadInt64();
+            break;
+          }
+          case 24: {
+            OptionalUint32 = input.ReadUInt32();
+            break;
+          }
+          case 32: {
+            OptionalUint64 = input.ReadUInt64();
+            break;
+          }
+          case 40: {
+            OptionalSint32 = input.ReadSInt32();
+            break;
+          }
+          case 48: {
+            OptionalSint64 = input.ReadSInt64();
+            break;
+          }
+          case 61: {
+            OptionalFixed32 = input.ReadFixed32();
+            break;
+          }
+          case 65: {
+            OptionalFixed64 = input.ReadFixed64();
+            break;
+          }
+          case 77: {
+            OptionalSfixed32 = input.ReadSFixed32();
+            break;
+          }
+          case 81: {
+            OptionalSfixed64 = input.ReadSFixed64();
+            break;
+          }
+          case 93: {
+            OptionalFloat = input.ReadFloat();
+            break;
+          }
+          case 97: {
+            OptionalDouble = input.ReadDouble();
+            break;
+          }
+          case 104: {
+            OptionalBool = input.ReadBool();
+            break;
+          }
+          case 114: {
+            OptionalString = input.ReadString();
+            break;
+          }
+          case 122: {
+            OptionalBytes = input.ReadBytes();
+            break;
+          }
+          case 146: {
+            if (optionalNestedMessage_ == null) {
+              OptionalNestedMessage = new global::ProtobufTestMessages.Proto3.TestAllTypesProto3.Types.NestedMessage();
+            }
+            input.ReadMessage(OptionalNestedMessage);
+            break;
+          }
+          case 154: {
+            if (optionalForeignMessage_ == null) {
+              OptionalForeignMessage = new global::ProtobufTestMessages.Proto3.ForeignMessage();
+            }
+            input.ReadMessage(OptionalForeignMessage);
+            break;
+          }
+          case 168: {
+            OptionalNestedEnum = (global::ProtobufTestMessages.Proto3.TestAllTypesProto3.Types.NestedEnum) input.ReadEnum();
+            break;
+          }
+          case 176: {
+            OptionalForeignEnum = (global::ProtobufTestMessages.Proto3.ForeignEnum) input.ReadEnum();
+            break;
+          }
+          case 184: {
+            OptionalAliasedEnum = (global::ProtobufTestMessages.Proto3.TestAllTypesProto3.Types.AliasedEnum) input.ReadEnum();
+            break;
+          }
+          case 194: {
+            OptionalStringPiece = input.ReadString();
+            break;
+          }
+          case 202: {
+            OptionalCord = input.ReadString();
+            break;
+          }
+          case 218: {
+            if (recursiveMessage_ == null) {
+              RecursiveMessage = new global::ProtobufTestMessages.Proto3.TestAllTypesProto3();
+            }
+            input.ReadMessage(RecursiveMessage);
+            break;
+          }
+          case 250:
+          case 248: {
+            repeatedInt32_.AddEntriesFrom(input, _repeated_repeatedInt32_codec);
+            break;
+          }
+          case 258:
+          case 256: {
+            repeatedInt64_.AddEntriesFrom(input, _repeated_repeatedInt64_codec);
+            break;
+          }
+          case 266:
+          case 264: {
+            repeatedUint32_.AddEntriesFrom(input, _repeated_repeatedUint32_codec);
+            break;
+          }
+          case 274:
+          case 272: {
+            repeatedUint64_.AddEntriesFrom(input, _repeated_repeatedUint64_codec);
+            break;
+          }
+          case 282:
+          case 280: {
+            repeatedSint32_.AddEntriesFrom(input, _repeated_repeatedSint32_codec);
+            break;
+          }
+          case 290:
+          case 288: {
+            repeatedSint64_.AddEntriesFrom(input, _repeated_repeatedSint64_codec);
+            break;
+          }
+          case 298:
+          case 301: {
+            repeatedFixed32_.AddEntriesFrom(input, _repeated_repeatedFixed32_codec);
+            break;
+          }
+          case 306:
+          case 305: {
+            repeatedFixed64_.AddEntriesFrom(input, _repeated_repeatedFixed64_codec);
+            break;
+          }
+          case 314:
+          case 317: {
+            repeatedSfixed32_.AddEntriesFrom(input, _repeated_repeatedSfixed32_codec);
+            break;
+          }
+          case 322:
+          case 321: {
+            repeatedSfixed64_.AddEntriesFrom(input, _repeated_repeatedSfixed64_codec);
+            break;
+          }
+          case 330:
+          case 333: {
+            repeatedFloat_.AddEntriesFrom(input, _repeated_repeatedFloat_codec);
+            break;
+          }
+          case 338:
+          case 337: {
+            repeatedDouble_.AddEntriesFrom(input, _repeated_repeatedDouble_codec);
+            break;
+          }
+          case 346:
+          case 344: {
+            repeatedBool_.AddEntriesFrom(input, _repeated_repeatedBool_codec);
+            break;
+          }
+          case 354: {
+            repeatedString_.AddEntriesFrom(input, _repeated_repeatedString_codec);
+            break;
+          }
+          case 362: {
+            repeatedBytes_.AddEntriesFrom(input, _repeated_repeatedBytes_codec);
+            break;
+          }
+          case 386: {
+            repeatedNestedMessage_.AddEntriesFrom(input, _repeated_repeatedNestedMessage_codec);
+            break;
+          }
+          case 394: {
+            repeatedForeignMessage_.AddEntriesFrom(input, _repeated_repeatedForeignMessage_codec);
+            break;
+          }
+          case 410:
+          case 408: {
+            repeatedNestedEnum_.AddEntriesFrom(input, _repeated_repeatedNestedEnum_codec);
+            break;
+          }
+          case 418:
+          case 416: {
+            repeatedForeignEnum_.AddEntriesFrom(input, _repeated_repeatedForeignEnum_codec);
+            break;
+          }
+          case 434: {
+            repeatedStringPiece_.AddEntriesFrom(input, _repeated_repeatedStringPiece_codec);
+            break;
+          }
+          case 442: {
+            repeatedCord_.AddEntriesFrom(input, _repeated_repeatedCord_codec);
+            break;
+          }
+          case 450: {
+            mapInt32Int32_.AddEntriesFrom(input, _map_mapInt32Int32_codec);
+            break;
+          }
+          case 458: {
+            mapInt64Int64_.AddEntriesFrom(input, _map_mapInt64Int64_codec);
+            break;
+          }
+          case 466: {
+            mapUint32Uint32_.AddEntriesFrom(input, _map_mapUint32Uint32_codec);
+            break;
+          }
+          case 474: {
+            mapUint64Uint64_.AddEntriesFrom(input, _map_mapUint64Uint64_codec);
+            break;
+          }
+          case 482: {
+            mapSint32Sint32_.AddEntriesFrom(input, _map_mapSint32Sint32_codec);
+            break;
+          }
+          case 490: {
+            mapSint64Sint64_.AddEntriesFrom(input, _map_mapSint64Sint64_codec);
+            break;
+          }
+          case 498: {
+            mapFixed32Fixed32_.AddEntriesFrom(input, _map_mapFixed32Fixed32_codec);
+            break;
+          }
+          case 506: {
+            mapFixed64Fixed64_.AddEntriesFrom(input, _map_mapFixed64Fixed64_codec);
+            break;
+          }
+          case 514: {
+            mapSfixed32Sfixed32_.AddEntriesFrom(input, _map_mapSfixed32Sfixed32_codec);
+            break;
+          }
+          case 522: {
+            mapSfixed64Sfixed64_.AddEntriesFrom(input, _map_mapSfixed64Sfixed64_codec);
+            break;
+          }
+          case 530: {
+            mapInt32Float_.AddEntriesFrom(input, _map_mapInt32Float_codec);
+            break;
+          }
+          case 538: {
+            mapInt32Double_.AddEntriesFrom(input, _map_mapInt32Double_codec);
+            break;
+          }
+          case 546: {
+            mapBoolBool_.AddEntriesFrom(input, _map_mapBoolBool_codec);
+            break;
+          }
+          case 554: {
+            mapStringString_.AddEntriesFrom(input, _map_mapStringString_codec);
+            break;
+          }
+          case 562: {
+            mapStringBytes_.AddEntriesFrom(input, _map_mapStringBytes_codec);
+            break;
+          }
+          case 570: {
+            mapStringNestedMessage_.AddEntriesFrom(input, _map_mapStringNestedMessage_codec);
+            break;
+          }
+          case 578: {
+            mapStringForeignMessage_.AddEntriesFrom(input, _map_mapStringForeignMessage_codec);
+            break;
+          }
+          case 586: {
+            mapStringNestedEnum_.AddEntriesFrom(input, _map_mapStringNestedEnum_codec);
+            break;
+          }
+          case 594: {
+            mapStringForeignEnum_.AddEntriesFrom(input, _map_mapStringForeignEnum_codec);
+            break;
+          }
+          case 602:
+          case 600: {
+            packedInt32_.AddEntriesFrom(input, _repeated_packedInt32_codec);
+            break;
+          }
+          case 610:
+          case 608: {
+            packedInt64_.AddEntriesFrom(input, _repeated_packedInt64_codec);
+            break;
+          }
+          case 618:
+          case 616: {
+            packedUint32_.AddEntriesFrom(input, _repeated_packedUint32_codec);
+            break;
+          }
+          case 626:
+          case 624: {
+            packedUint64_.AddEntriesFrom(input, _repeated_packedUint64_codec);
+            break;
+          }
+          case 634:
+          case 632: {
+            packedSint32_.AddEntriesFrom(input, _repeated_packedSint32_codec);
+            break;
+          }
+          case 642:
+          case 640: {
+            packedSint64_.AddEntriesFrom(input, _repeated_packedSint64_codec);
+            break;
+          }
+          case 650:
+          case 653: {
+            packedFixed32_.AddEntriesFrom(input, _repeated_packedFixed32_codec);
+            break;
+          }
+          case 658:
+          case 657: {
+            packedFixed64_.AddEntriesFrom(input, _repeated_packedFixed64_codec);
+            break;
+          }
+          case 666:
+          case 669: {
+            packedSfixed32_.AddEntriesFrom(input, _repeated_packedSfixed32_codec);
+            break;
+          }
+          case 674:
+          case 673: {
+            packedSfixed64_.AddEntriesFrom(input, _repeated_packedSfixed64_codec);
+            break;
+          }
+          case 682:
+          case 685: {
+            packedFloat_.AddEntriesFrom(input, _repeated_packedFloat_codec);
+            break;
+          }
+          case 690:
+          case 689: {
+            packedDouble_.AddEntriesFrom(input, _repeated_packedDouble_codec);
+            break;
+          }
+          case 698:
+          case 696: {
+            packedBool_.AddEntriesFrom(input, _repeated_packedBool_codec);
+            break;
+          }
+          case 706:
+          case 704: {
+            packedNestedEnum_.AddEntriesFrom(input, _repeated_packedNestedEnum_codec);
+            break;
+          }
+          case 714:
+          case 712: {
+            unpackedInt32_.AddEntriesFrom(input, _repeated_unpackedInt32_codec);
+            break;
+          }
+          case 722:
+          case 720: {
+            unpackedInt64_.AddEntriesFrom(input, _repeated_unpackedInt64_codec);
+            break;
+          }
+          case 730:
+          case 728: {
+            unpackedUint32_.AddEntriesFrom(input, _repeated_unpackedUint32_codec);
+            break;
+          }
+          case 738:
+          case 736: {
+            unpackedUint64_.AddEntriesFrom(input, _repeated_unpackedUint64_codec);
+            break;
+          }
+          case 746:
+          case 744: {
+            unpackedSint32_.AddEntriesFrom(input, _repeated_unpackedSint32_codec);
+            break;
+          }
+          case 754:
+          case 752: {
+            unpackedSint64_.AddEntriesFrom(input, _repeated_unpackedSint64_codec);
+            break;
+          }
+          case 762:
+          case 765: {
+            unpackedFixed32_.AddEntriesFrom(input, _repeated_unpackedFixed32_codec);
+            break;
+          }
+          case 770:
+          case 769: {
+            unpackedFixed64_.AddEntriesFrom(input, _repeated_unpackedFixed64_codec);
+            break;
+          }
+          case 778:
+          case 781: {
+            unpackedSfixed32_.AddEntriesFrom(input, _repeated_unpackedSfixed32_codec);
+            break;
+          }
+          case 786:
+          case 785: {
+            unpackedSfixed64_.AddEntriesFrom(input, _repeated_unpackedSfixed64_codec);
+            break;
+          }
+          case 794:
+          case 797: {
+            unpackedFloat_.AddEntriesFrom(input, _repeated_unpackedFloat_codec);
+            break;
+          }
+          case 802:
+          case 801: {
+            unpackedDouble_.AddEntriesFrom(input, _repeated_unpackedDouble_codec);
+            break;
+          }
+          case 810:
+          case 808: {
+            unpackedBool_.AddEntriesFrom(input, _repeated_unpackedBool_codec);
+            break;
+          }
+          case 818:
+          case 816: {
+            unpackedNestedEnum_.AddEntriesFrom(input, _repeated_unpackedNestedEnum_codec);
+            break;
+          }
+          case 888: {
+            OneofUint32 = input.ReadUInt32();
+            break;
+          }
+          case 898: {
+            global::ProtobufTestMessages.Proto3.TestAllTypesProto3.Types.NestedMessage subBuilder = new global::ProtobufTestMessages.Proto3.TestAllTypesProto3.Types.NestedMessage();
+            if (oneofFieldCase_ == OneofFieldOneofCase.OneofNestedMessage) {
+              subBuilder.MergeFrom(OneofNestedMessage);
+            }
+            input.ReadMessage(subBuilder);
+            OneofNestedMessage = subBuilder;
+            break;
+          }
+          case 906: {
+            OneofString = input.ReadString();
+            break;
+          }
+          case 914: {
+            OneofBytes = input.ReadBytes();
+            break;
+          }
+          case 920: {
+            OneofBool = input.ReadBool();
+            break;
+          }
+          case 928: {
+            OneofUint64 = input.ReadUInt64();
+            break;
+          }
+          case 941: {
+            OneofFloat = input.ReadFloat();
+            break;
+          }
+          case 945: {
+            OneofDouble = input.ReadDouble();
+            break;
+          }
+          case 952: {
+            oneofField_ = input.ReadEnum();
+            oneofFieldCase_ = OneofFieldOneofCase.OneofEnum;
+            break;
+          }
+          case 1610: {
+            bool? value = _single_optionalBoolWrapper_codec.Read(input);
+            if (optionalBoolWrapper_ == null || value != false) {
+              OptionalBoolWrapper = value;
+            }
+            break;
+          }
+          case 1618: {
+            int? value = _single_optionalInt32Wrapper_codec.Read(input);
+            if (optionalInt32Wrapper_ == null || value != 0) {
+              OptionalInt32Wrapper = value;
+            }
+            break;
+          }
+          case 1626: {
+            long? value = _single_optionalInt64Wrapper_codec.Read(input);
+            if (optionalInt64Wrapper_ == null || value != 0L) {
+              OptionalInt64Wrapper = value;
+            }
+            break;
+          }
+          case 1634: {
+            uint? value = _single_optionalUint32Wrapper_codec.Read(input);
+            if (optionalUint32Wrapper_ == null || value != 0) {
+              OptionalUint32Wrapper = value;
+            }
+            break;
+          }
+          case 1642: {
+            ulong? value = _single_optionalUint64Wrapper_codec.Read(input);
+            if (optionalUint64Wrapper_ == null || value != 0UL) {
+              OptionalUint64Wrapper = value;
+            }
+            break;
+          }
+          case 1650: {
+            float? value = _single_optionalFloatWrapper_codec.Read(input);
+            if (optionalFloatWrapper_ == null || value != 0F) {
+              OptionalFloatWrapper = value;
+            }
+            break;
+          }
+          case 1658: {
+            double? value = _single_optionalDoubleWrapper_codec.Read(input);
+            if (optionalDoubleWrapper_ == null || value != 0D) {
+              OptionalDoubleWrapper = value;
+            }
+            break;
+          }
+          case 1666: {
+            string value = _single_optionalStringWrapper_codec.Read(input);
+            if (optionalStringWrapper_ == null || value != "") {
+              OptionalStringWrapper = value;
+            }
+            break;
+          }
+          case 1674: {
+            pb::ByteString value = _single_optionalBytesWrapper_codec.Read(input);
+            if (optionalBytesWrapper_ == null || value != pb::ByteString.Empty) {
+              OptionalBytesWrapper = value;
+            }
+            break;
+          }
+          case 1690: {
+            repeatedBoolWrapper_.AddEntriesFrom(input, _repeated_repeatedBoolWrapper_codec);
+            break;
+          }
+          case 1698: {
+            repeatedInt32Wrapper_.AddEntriesFrom(input, _repeated_repeatedInt32Wrapper_codec);
+            break;
+          }
+          case 1706: {
+            repeatedInt64Wrapper_.AddEntriesFrom(input, _repeated_repeatedInt64Wrapper_codec);
+            break;
+          }
+          case 1714: {
+            repeatedUint32Wrapper_.AddEntriesFrom(input, _repeated_repeatedUint32Wrapper_codec);
+            break;
+          }
+          case 1722: {
+            repeatedUint64Wrapper_.AddEntriesFrom(input, _repeated_repeatedUint64Wrapper_codec);
+            break;
+          }
+          case 1730: {
+            repeatedFloatWrapper_.AddEntriesFrom(input, _repeated_repeatedFloatWrapper_codec);
+            break;
+          }
+          case 1738: {
+            repeatedDoubleWrapper_.AddEntriesFrom(input, _repeated_repeatedDoubleWrapper_codec);
+            break;
+          }
+          case 1746: {
+            repeatedStringWrapper_.AddEntriesFrom(input, _repeated_repeatedStringWrapper_codec);
+            break;
+          }
+          case 1754: {
+            repeatedBytesWrapper_.AddEntriesFrom(input, _repeated_repeatedBytesWrapper_codec);
+            break;
+          }
+          case 2410: {
+            if (optionalDuration_ == null) {
+              OptionalDuration = new global::Google.Protobuf.WellKnownTypes.Duration();
+            }
+            input.ReadMessage(OptionalDuration);
+            break;
+          }
+          case 2418: {
+            if (optionalTimestamp_ == null) {
+              OptionalTimestamp = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+            }
+            input.ReadMessage(OptionalTimestamp);
+            break;
+          }
+          case 2426: {
+            if (optionalFieldMask_ == null) {
+              OptionalFieldMask = new global::Google.Protobuf.WellKnownTypes.FieldMask();
+            }
+            input.ReadMessage(OptionalFieldMask);
+            break;
+          }
+          case 2434: {
+            if (optionalStruct_ == null) {
+              OptionalStruct = new global::Google.Protobuf.WellKnownTypes.Struct();
+            }
+            input.ReadMessage(OptionalStruct);
+            break;
+          }
+          case 2442: {
+            if (optionalAny_ == null) {
+              OptionalAny = new global::Google.Protobuf.WellKnownTypes.Any();
+            }
+            input.ReadMessage(OptionalAny);
+            break;
+          }
+          case 2450: {
+            if (optionalValue_ == null) {
+              OptionalValue = new global::Google.Protobuf.WellKnownTypes.Value();
+            }
+            input.ReadMessage(OptionalValue);
+            break;
+          }
+          case 2490: {
+            repeatedDuration_.AddEntriesFrom(input, _repeated_repeatedDuration_codec);
+            break;
+          }
+          case 2498: {
+            repeatedTimestamp_.AddEntriesFrom(input, _repeated_repeatedTimestamp_codec);
+            break;
+          }
+          case 2506: {
+            repeatedFieldmask_.AddEntriesFrom(input, _repeated_repeatedFieldmask_codec);
+            break;
+          }
+          case 2522: {
+            repeatedAny_.AddEntriesFrom(input, _repeated_repeatedAny_codec);
+            break;
+          }
+          case 2530: {
+            repeatedValue_.AddEntriesFrom(input, _repeated_repeatedValue_codec);
+            break;
+          }
+          case 2538: {
+            repeatedListValue_.AddEntriesFrom(input, _repeated_repeatedListValue_codec);
+            break;
+          }
+          case 2594: {
+            repeatedStruct_.AddEntriesFrom(input, _repeated_repeatedStruct_codec);
+            break;
+          }
+          case 3208: {
+            Fieldname1 = input.ReadInt32();
+            break;
+          }
+          case 3216: {
+            FieldName2 = input.ReadInt32();
+            break;
+          }
+          case 3224: {
+            FieldName3 = input.ReadInt32();
+            break;
+          }
+          case 3232: {
+            FieldName4 = input.ReadInt32();
+            break;
+          }
+          case 3240: {
+            Field0Name5 = input.ReadInt32();
+            break;
+          }
+          case 3248: {
+            Field0Name6 = input.ReadInt32();
+            break;
+          }
+          case 3256: {
+            FieldName7 = input.ReadInt32();
+            break;
+          }
+          case 3264: {
+            FieldName8 = input.ReadInt32();
+            break;
+          }
+          case 3272: {
+            FieldName9 = input.ReadInt32();
+            break;
+          }
+          case 3280: {
+            FieldName10 = input.ReadInt32();
+            break;
+          }
+          case 3288: {
+            FIELDNAME11 = input.ReadInt32();
+            break;
+          }
+          case 3296: {
+            FIELDName12 = input.ReadInt32();
+            break;
+          }
+          case 3304: {
+            FieldName13 = input.ReadInt32();
+            break;
+          }
+          case 3312: {
+            FieldName14 = input.ReadInt32();
+            break;
+          }
+          case 3320: {
+            FieldName15 = input.ReadInt32();
+            break;
+          }
+          case 3328: {
+            FieldName16 = input.ReadInt32();
+            break;
+          }
+          case 3336: {
+            FieldName17 = input.ReadInt32();
+            break;
+          }
+          case 3344: {
+            FieldName18 = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -4096,6 +4811,7 @@ namespace ProtobufTestMessages.Proto3 {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the TestAllTypesProto3 message type.</summary>
@@ -4120,7 +4836,11 @@ namespace ProtobufTestMessages.Proto3 {
         [pbr::OriginalName("bAz", PreferredAlias = false)] BAz = 2,
       }
 
-      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>, pb::IBufferMessage {
+      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<NestedMessage> _parser = new pb::MessageParser<NestedMessage>(() => new NestedMessage());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -4260,9 +4980,32 @@ namespace ProtobufTestMessages.Proto3 {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                A = input.ReadInt32();
+                break;
+              }
+              case 18: {
+                if (corecursive_ == null) {
+                  Corecursive = new global::ProtobufTestMessages.Proto3.TestAllTypesProto3();
+                }
+                input.ReadMessage(Corecursive);
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -4285,6 +5028,7 @@ namespace ProtobufTestMessages.Proto3 {
             }
           }
         }
+        #endif
 
       }
 
@@ -4293,7 +5037,11 @@ namespace ProtobufTestMessages.Proto3 {
 
   }
 
-  public sealed partial class ForeignMessage : pb::IMessage<ForeignMessage>, pb::IBufferMessage {
+  public sealed partial class ForeignMessage : pb::IMessage<ForeignMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ForeignMessage> _parser = new pb::MessageParser<ForeignMessage>(() => new ForeignMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -4406,9 +5154,25 @@ namespace ProtobufTestMessages.Proto3 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            C = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -4424,6 +5188,7 @@ namespace ProtobufTestMessages.Proto3 {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestCustomOptionsProto3.cs

@@ -257,7 +257,11 @@ namespace UnitTest.Issues.TestProtos {
   /// A test message with custom options at all possible locations (and also some
   /// regular options, to make sure they interact nicely).
   /// </summary>
-  public sealed partial class TestMessageWithCustomOptions : pb::IMessage<TestMessageWithCustomOptions>, pb::IBufferMessage {
+  public sealed partial class TestMessageWithCustomOptions : pb::IMessage<TestMessageWithCustomOptions>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestMessageWithCustomOptions> _parser = new pb::MessageParser<TestMessageWithCustomOptions>(() => new TestMessageWithCustomOptions());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -422,9 +426,29 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Field1 = input.ReadString();
+            break;
+          }
+          case 16: {
+            OneofField = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -444,6 +468,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the TestMessageWithCustomOptions message type.</summary>
@@ -464,7 +489,11 @@ namespace UnitTest.Issues.TestProtos {
   /// A test RPC service with custom options at all possible locations (and also
   /// some regular options, to make sure they interact nicely).
   /// </summary>
-  public sealed partial class CustomOptionFooRequest : pb::IMessage<CustomOptionFooRequest>, pb::IBufferMessage {
+  public sealed partial class CustomOptionFooRequest : pb::IMessage<CustomOptionFooRequest>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionFooRequest> _parser = new pb::MessageParser<CustomOptionFooRequest>(() => new CustomOptionFooRequest());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -553,9 +582,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -567,10 +608,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class CustomOptionFooResponse : pb::IMessage<CustomOptionFooResponse>, pb::IBufferMessage {
+  public sealed partial class CustomOptionFooResponse : pb::IMessage<CustomOptionFooResponse>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionFooResponse> _parser = new pb::MessageParser<CustomOptionFooResponse>(() => new CustomOptionFooResponse());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -659,9 +705,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -673,10 +731,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class CustomOptionFooClientMessage : pb::IMessage<CustomOptionFooClientMessage>, pb::IBufferMessage {
+  public sealed partial class CustomOptionFooClientMessage : pb::IMessage<CustomOptionFooClientMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionFooClientMessage> _parser = new pb::MessageParser<CustomOptionFooClientMessage>(() => new CustomOptionFooClientMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -765,9 +828,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -779,10 +854,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class CustomOptionFooServerMessage : pb::IMessage<CustomOptionFooServerMessage>, pb::IBufferMessage {
+  public sealed partial class CustomOptionFooServerMessage : pb::IMessage<CustomOptionFooServerMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionFooServerMessage> _parser = new pb::MessageParser<CustomOptionFooServerMessage>(() => new CustomOptionFooServerMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -871,9 +951,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -885,10 +977,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class DummyMessageContainingEnum : pb::IMessage<DummyMessageContainingEnum>, pb::IBufferMessage {
+  public sealed partial class DummyMessageContainingEnum : pb::IMessage<DummyMessageContainingEnum>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<DummyMessageContainingEnum> _parser = new pb::MessageParser<DummyMessageContainingEnum>(() => new DummyMessageContainingEnum());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -977,9 +1074,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -991,6 +1100,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the DummyMessageContainingEnum message type.</summary>
@@ -1007,7 +1117,11 @@ namespace UnitTest.Issues.TestProtos {
 
   }
 
-  public sealed partial class DummyMessageInvalidAsOptionType : pb::IMessage<DummyMessageInvalidAsOptionType>, pb::IBufferMessage {
+  public sealed partial class DummyMessageInvalidAsOptionType : pb::IMessage<DummyMessageInvalidAsOptionType>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<DummyMessageInvalidAsOptionType> _parser = new pb::MessageParser<DummyMessageInvalidAsOptionType>(() => new DummyMessageInvalidAsOptionType());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1096,9 +1210,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1110,10 +1236,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class CustomOptionMinIntegerValues : pb::IMessage<CustomOptionMinIntegerValues>, pb::IBufferMessage {
+  public sealed partial class CustomOptionMinIntegerValues : pb::IMessage<CustomOptionMinIntegerValues>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionMinIntegerValues> _parser = new pb::MessageParser<CustomOptionMinIntegerValues>(() => new CustomOptionMinIntegerValues());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1202,9 +1333,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1216,10 +1359,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class CustomOptionMaxIntegerValues : pb::IMessage<CustomOptionMaxIntegerValues>, pb::IBufferMessage {
+  public sealed partial class CustomOptionMaxIntegerValues : pb::IMessage<CustomOptionMaxIntegerValues>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionMaxIntegerValues> _parser = new pb::MessageParser<CustomOptionMaxIntegerValues>(() => new CustomOptionMaxIntegerValues());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1308,9 +1456,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1322,10 +1482,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class CustomOptionOtherValues : pb::IMessage<CustomOptionOtherValues>, pb::IBufferMessage {
+  public sealed partial class CustomOptionOtherValues : pb::IMessage<CustomOptionOtherValues>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<CustomOptionOtherValues> _parser = new pb::MessageParser<CustomOptionOtherValues>(() => new CustomOptionOtherValues());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1414,9 +1579,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1428,10 +1605,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class SettingRealsFromPositiveInts : pb::IMessage<SettingRealsFromPositiveInts>, pb::IBufferMessage {
+  public sealed partial class SettingRealsFromPositiveInts : pb::IMessage<SettingRealsFromPositiveInts>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<SettingRealsFromPositiveInts> _parser = new pb::MessageParser<SettingRealsFromPositiveInts>(() => new SettingRealsFromPositiveInts());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1520,9 +1702,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1534,10 +1728,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class SettingRealsFromNegativeInts : pb::IMessage<SettingRealsFromNegativeInts>, pb::IBufferMessage {
+  public sealed partial class SettingRealsFromNegativeInts : pb::IMessage<SettingRealsFromNegativeInts>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<SettingRealsFromNegativeInts> _parser = new pb::MessageParser<SettingRealsFromNegativeInts>(() => new SettingRealsFromNegativeInts());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1626,9 +1825,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1640,10 +1851,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class ComplexOptionType1 : pb::IMessage<ComplexOptionType1>, pb::IBufferMessage {
+  public sealed partial class ComplexOptionType1 : pb::IMessage<ComplexOptionType1>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ComplexOptionType1> _parser = new pb::MessageParser<ComplexOptionType1>(() => new ComplexOptionType1());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1820,9 +2036,38 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Foo = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            Foo2 = input.ReadInt32();
+            break;
+          }
+          case 24: {
+            Foo3 = input.ReadInt32();
+            break;
+          }
+          case 34:
+          case 32: {
+            foo4_.AddEntriesFrom(input, _repeated_foo4_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1851,10 +2096,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class ComplexOptionType2 : pb::IMessage<ComplexOptionType2>, pb::IBufferMessage {
+  public sealed partial class ComplexOptionType2 : pb::IMessage<ComplexOptionType2>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ComplexOptionType2> _parser = new pb::MessageParser<ComplexOptionType2>(() => new ComplexOptionType2());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2037,9 +2287,43 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            if (bar_ == null) {
+              Bar = new global::UnitTest.Issues.TestProtos.ComplexOptionType1();
+            }
+            input.ReadMessage(Bar);
+            break;
+          }
+          case 16: {
+            Baz = input.ReadInt32();
+            break;
+          }
+          case 26: {
+            if (fred_ == null) {
+              Fred = new global::UnitTest.Issues.TestProtos.ComplexOptionType2.Types.ComplexOptionType4();
+            }
+            input.ReadMessage(Fred);
+            break;
+          }
+          case 34: {
+            barney_.AddEntriesFrom(input, _repeated_barney_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2073,12 +2357,17 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the ComplexOptionType2 message type.</summary>
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public static partial class Types {
-      public sealed partial class ComplexOptionType4 : pb::IMessage<ComplexOptionType4>, pb::IBufferMessage {
+      public sealed partial class ComplexOptionType4 : pb::IMessage<ComplexOptionType4>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<ComplexOptionType4> _parser = new pb::MessageParser<ComplexOptionType4>(() => new ComplexOptionType4());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2191,9 +2480,25 @@ namespace UnitTest.Issues.TestProtos {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                Waldo = input.ReadInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -2209,6 +2514,7 @@ namespace UnitTest.Issues.TestProtos {
             }
           }
         }
+        #endif
 
         #region Extensions
         /// <summary>Container for extensions for other messages declared in the ComplexOptionType4 message type.</summary>
@@ -2226,7 +2532,11 @@ namespace UnitTest.Issues.TestProtos {
 
   }
 
-  public sealed partial class ComplexOptionType3 : pb::IMessage<ComplexOptionType3>, pb::IBufferMessage {
+  public sealed partial class ComplexOptionType3 : pb::IMessage<ComplexOptionType3>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ComplexOptionType3> _parser = new pb::MessageParser<ComplexOptionType3>(() => new ComplexOptionType3());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2339,9 +2649,25 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Qux = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2357,13 +2683,18 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Note that we try various different ways of naming the same extension.
   /// </summary>
-  public sealed partial class VariousComplexOptions : pb::IMessage<VariousComplexOptions>, pb::IBufferMessage {
+  public sealed partial class VariousComplexOptions : pb::IMessage<VariousComplexOptions>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<VariousComplexOptions> _parser = new pb::MessageParser<VariousComplexOptions>(() => new VariousComplexOptions());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2452,9 +2783,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2466,13 +2809,18 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// A helper type used to test aggregate option parsing
   /// </summary>
-  public sealed partial class Aggregate : pb::IMessage<Aggregate>, pb::IBufferMessage {
+  public sealed partial class Aggregate : pb::IMessage<Aggregate>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Aggregate> _parser = new pb::MessageParser<Aggregate>(() => new Aggregate());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2639,9 +2987,36 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            I = input.ReadInt32();
+            break;
+          }
+          case 18: {
+            S = input.ReadString();
+            break;
+          }
+          case 26: {
+            if (sub_ == null) {
+              Sub = new global::UnitTest.Issues.TestProtos.Aggregate();
+            }
+            input.ReadMessage(Sub);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2668,10 +3043,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class AggregateMessage : pb::IMessage<AggregateMessage>, pb::IBufferMessage {
+  public sealed partial class AggregateMessage : pb::IMessage<AggregateMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<AggregateMessage> _parser = new pb::MessageParser<AggregateMessage>(() => new AggregateMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2784,9 +3164,25 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Fieldname = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2802,13 +3198,18 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Test custom options for nested type.
   /// </summary>
-  public sealed partial class NestedOptionType : pb::IMessage<NestedOptionType>, pb::IBufferMessage {
+  public sealed partial class NestedOptionType : pb::IMessage<NestedOptionType>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<NestedOptionType> _parser = new pb::MessageParser<NestedOptionType>(() => new NestedOptionType());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2897,9 +3298,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2911,6 +3324,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the NestedOptionType message type.</summary>
@@ -2921,7 +3335,11 @@ namespace UnitTest.Issues.TestProtos {
         [pbr::OriginalName("NESTED_ENUM_VALUE")] Value = 1,
       }
 
-      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>, pb::IBufferMessage {
+      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<NestedMessage> _parser = new pb::MessageParser<NestedMessage>(() => new NestedMessage());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -3034,9 +3452,25 @@ namespace UnitTest.Issues.TestProtos {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                NestedField = input.ReadInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -3052,6 +3486,7 @@ namespace UnitTest.Issues.TestProtos {
             }
           }
         }
+        #endif
 
       }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestImport.cs

@@ -59,7 +59,11 @@ namespace Google.Protobuf.TestProtos.Proto2 {
   #endregion
 
   #region Messages
-  public sealed partial class ImportMessage : pb::IMessage<ImportMessage>, pb::IBufferMessage {
+  public sealed partial class ImportMessage : pb::IMessage<ImportMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ImportMessage> _parser = new pb::MessageParser<ImportMessage>(() => new ImportMessage());
     private pb::UnknownFieldSet _unknownFields;
     private int _hasBits0;
@@ -187,9 +191,25 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            D = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -205,6 +225,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportProto3.cs

@@ -50,7 +50,11 @@ namespace Google.Protobuf.TestProtos {
   #endregion
 
   #region Messages
-  public sealed partial class ImportMessage : pb::IMessage<ImportMessage>, pb::IBufferMessage {
+  public sealed partial class ImportMessage : pb::IMessage<ImportMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ImportMessage> _parser = new pb::MessageParser<ImportMessage>(() => new ImportMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -163,9 +167,25 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            D = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -181,6 +201,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportPublic.cs

@@ -37,7 +37,11 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
   }
   #region Messages
-  public sealed partial class PublicImportMessage : pb::IMessage<PublicImportMessage>, pb::IBufferMessage {
+  public sealed partial class PublicImportMessage : pb::IMessage<PublicImportMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<PublicImportMessage> _parser = new pb::MessageParser<PublicImportMessage>(() => new PublicImportMessage());
     private pb::UnknownFieldSet _unknownFields;
     private int _hasBits0;
@@ -165,9 +169,25 @@ namespace Google.Protobuf.TestProtos.Proto2 {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            E = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -183,6 +203,7 @@ namespace Google.Protobuf.TestProtos.Proto2 {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportPublicProto3.cs

@@ -38,7 +38,11 @@ namespace Google.Protobuf.TestProtos {
 
   }
   #region Messages
-  public sealed partial class PublicImportMessage : pb::IMessage<PublicImportMessage>, pb::IBufferMessage {
+  public sealed partial class PublicImportMessage : pb::IMessage<PublicImportMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<PublicImportMessage> _parser = new pb::MessageParser<PublicImportMessage>(() => new PublicImportMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -151,9 +155,25 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            E = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -169,6 +189,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestIssue6936B.cs

@@ -37,7 +37,11 @@ namespace UnitTest.Issues.TestProtos {
 
   }
   #region Messages
-  public sealed partial class Foo : pb::IMessage<Foo>, pb::IBufferMessage {
+  public sealed partial class Foo : pb::IMessage<Foo>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Foo> _parser = new pb::MessageParser<Foo>(() => new Foo());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -126,9 +130,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -140,6 +156,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestIssue6936C.cs

@@ -39,7 +39,11 @@ namespace UnitTest.Issues.TestProtos {
 
   }
   #region Messages
-  public sealed partial class Bar : pb::IMessage<Bar>, pb::IBufferMessage {
+  public sealed partial class Bar : pb::IMessage<Bar>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Bar> _parser = new pb::MessageParser<Bar>(() => new Bar());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -155,9 +159,28 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            if (foo_ == null) {
+              Foo = new global::UnitTest.Issues.TestProtos.Foo();
+            }
+            input.ReadMessage(Foo);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -176,6 +199,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestIssues.cs

@@ -88,7 +88,11 @@ namespace UnitTest.Issues.TestProtos {
   /// Issue 307: when generating doubly-nested types, any references
   /// should be of the form A.Types.B.Types.C.
   /// </summary>
-  public sealed partial class Issue307 : pb::IMessage<Issue307>, pb::IBufferMessage {
+  public sealed partial class Issue307 : pb::IMessage<Issue307>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Issue307> _parser = new pb::MessageParser<Issue307>(() => new Issue307());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -177,9 +181,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -191,12 +207,17 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the Issue307 message type.</summary>
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public static partial class Types {
-      public sealed partial class NestedOnce : pb::IMessage<NestedOnce>, pb::IBufferMessage {
+      public sealed partial class NestedOnce : pb::IMessage<NestedOnce>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<NestedOnce> _parser = new pb::MessageParser<NestedOnce>(() => new NestedOnce());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -285,9 +306,21 @@ namespace UnitTest.Issues.TestProtos {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -299,12 +332,17 @@ namespace UnitTest.Issues.TestProtos {
             }
           }
         }
+        #endif
 
         #region Nested types
         /// <summary>Container for nested types declared in the NestedOnce message type.</summary>
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public static partial class Types {
-          public sealed partial class NestedTwice : pb::IMessage<NestedTwice>, pb::IBufferMessage {
+          public sealed partial class NestedTwice : pb::IMessage<NestedTwice>
+          #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+              , pb::IBufferMessage
+          #endif
+          {
             private static readonly pb::MessageParser<NestedTwice> _parser = new pb::MessageParser<NestedTwice>(() => new NestedTwice());
             private pb::UnknownFieldSet _unknownFields;
             [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -393,9 +431,21 @@ namespace UnitTest.Issues.TestProtos {
 
             [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
             public void MergeFrom(pb::CodedInputStream input) {
+            #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
               input.ReadRawMessage(this);
+            #else
+              uint tag;
+              while ((tag = input.ReadTag()) != 0) {
+                switch(tag) {
+                  default:
+                    _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                    break;
+                }
+              }
+            #endif
             }
 
+            #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
             [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
             void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
               uint tag;
@@ -407,6 +457,7 @@ namespace UnitTest.Issues.TestProtos {
                 }
               }
             }
+            #endif
 
           }
 
@@ -420,7 +471,11 @@ namespace UnitTest.Issues.TestProtos {
 
   }
 
-  public sealed partial class NegativeEnumMessage : pb::IMessage<NegativeEnumMessage>, pb::IBufferMessage {
+  public sealed partial class NegativeEnumMessage : pb::IMessage<NegativeEnumMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<NegativeEnumMessage> _parser = new pb::MessageParser<NegativeEnumMessage>(() => new NegativeEnumMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -565,9 +620,35 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Value = (global::UnitTest.Issues.TestProtos.NegativeEnum) input.ReadEnum();
+            break;
+          }
+          case 18:
+          case 16: {
+            values_.AddEntriesFrom(input, _repeated_values_codec);
+            break;
+          }
+          case 26:
+          case 24: {
+            packedValues_.AddEntriesFrom(input, _repeated_packedValues_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -593,10 +674,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class DeprecatedChild : pb::IMessage<DeprecatedChild>, pb::IBufferMessage {
+  public sealed partial class DeprecatedChild : pb::IMessage<DeprecatedChild>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<DeprecatedChild> _parser = new pb::MessageParser<DeprecatedChild>(() => new DeprecatedChild());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -685,9 +771,21 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -699,10 +797,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class DeprecatedFieldsMessage : pb::IMessage<DeprecatedFieldsMessage>, pb::IBufferMessage {
+  public sealed partial class DeprecatedFieldsMessage : pb::IMessage<DeprecatedFieldsMessage>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<DeprecatedFieldsMessage> _parser = new pb::MessageParser<DeprecatedFieldsMessage>(() => new DeprecatedFieldsMessage());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -920,9 +1023,50 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            PrimitiveValue = input.ReadInt32();
+            break;
+          }
+          case 18:
+          case 16: {
+            primitiveArray_.AddEntriesFrom(input, _repeated_primitiveArray_codec);
+            break;
+          }
+          case 26: {
+            if (messageValue_ == null) {
+              MessageValue = new global::UnitTest.Issues.TestProtos.DeprecatedChild();
+            }
+            input.ReadMessage(MessageValue);
+            break;
+          }
+          case 34: {
+            messageArray_.AddEntriesFrom(input, _repeated_messageArray_codec);
+            break;
+          }
+          case 40: {
+            EnumValue = (global::UnitTest.Issues.TestProtos.DeprecatedEnum) input.ReadEnum();
+            break;
+          }
+          case 50:
+          case 48: {
+            enumArray_.AddEntriesFrom(input, _repeated_enumArray_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -963,13 +1107,18 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Issue 45: http://code.google.com/p/protobuf-csharp-port/issues/detail?id=45
   /// </summary>
-  public sealed partial class ItemField : pb::IMessage<ItemField>, pb::IBufferMessage {
+  public sealed partial class ItemField : pb::IMessage<ItemField>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ItemField> _parser = new pb::MessageParser<ItemField>(() => new ItemField());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1082,9 +1231,25 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Item = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1100,10 +1265,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class ReservedNames : pb::IMessage<ReservedNames>, pb::IBufferMessage {
+  public sealed partial class ReservedNames : pb::IMessage<ReservedNames>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ReservedNames> _parser = new pb::MessageParser<ReservedNames>(() => new ReservedNames());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1240,9 +1410,29 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Types_ = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            Descriptor_ = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1262,6 +1452,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the ReservedNames message type.</summary>
@@ -1270,7 +1461,11 @@ namespace UnitTest.Issues.TestProtos {
       /// <summary>
       /// Force a nested type called Types
       /// </summary>
-      public sealed partial class SomeNestedType : pb::IMessage<SomeNestedType>, pb::IBufferMessage {
+      public sealed partial class SomeNestedType : pb::IMessage<SomeNestedType>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<SomeNestedType> _parser = new pb::MessageParser<SomeNestedType>(() => new SomeNestedType());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1359,9 +1554,21 @@ namespace UnitTest.Issues.TestProtos {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -1373,6 +1580,7 @@ namespace UnitTest.Issues.TestProtos {
             }
           }
         }
+        #endif
 
       }
 
@@ -1393,7 +1601,11 @@ namespace UnitTest.Issues.TestProtos {
   /// Alternatively, consider just adding this to
   /// unittest_proto3.proto if multiple platforms want it.
   /// </summary>
-  public sealed partial class TestJsonFieldOrdering : pb::IMessage<TestJsonFieldOrdering>, pb::IBufferMessage {
+  public sealed partial class TestJsonFieldOrdering : pb::IMessage<TestJsonFieldOrdering>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestJsonFieldOrdering> _parser = new pb::MessageParser<TestJsonFieldOrdering>(() => new TestJsonFieldOrdering());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1688,9 +1900,45 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            PlainString = input.ReadString();
+            break;
+          }
+          case 18: {
+            O1String = input.ReadString();
+            break;
+          }
+          case 26: {
+            O2String = input.ReadString();
+            break;
+          }
+          case 32: {
+            PlainInt32 = input.ReadInt32();
+            break;
+          }
+          case 40: {
+            O1Int32 = input.ReadInt32();
+            break;
+          }
+          case 48: {
+            O2Int32 = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1726,10 +1974,15 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class TestJsonName : pb::IMessage<TestJsonName>, pb::IBufferMessage {
+  public sealed partial class TestJsonName : pb::IMessage<TestJsonName>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestJsonName> _parser = new pb::MessageParser<TestJsonName>(() => new TestJsonName());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1893,9 +2146,33 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            Description = input.ReadString();
+            break;
+          }
+          case 26: {
+            Guid = input.ReadString();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1919,6 +2196,7 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
@@ -1927,7 +2205,11 @@ namespace UnitTest.Issues.TestProtos {
   /// oneof case, which is itself a message type, the submessages should
   /// be merged.
   /// </summary>
-  public sealed partial class OneofMerging : pb::IMessage<OneofMerging>, pb::IBufferMessage {
+  public sealed partial class OneofMerging : pb::IMessage<OneofMerging>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<OneofMerging> _parser = new pb::MessageParser<OneofMerging>(() => new OneofMerging());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2098,9 +2380,34 @@ namespace UnitTest.Issues.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Text = input.ReadString();
+            break;
+          }
+          case 18: {
+            global::UnitTest.Issues.TestProtos.OneofMerging.Types.Nested subBuilder = new global::UnitTest.Issues.TestProtos.OneofMerging.Types.Nested();
+            if (valueCase_ == ValueOneofCase.Nested) {
+              subBuilder.MergeFrom(Nested);
+            }
+            input.ReadMessage(subBuilder);
+            Nested = subBuilder;
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2125,12 +2432,17 @@ namespace UnitTest.Issues.TestProtos {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the OneofMerging message type.</summary>
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public static partial class Types {
-      public sealed partial class Nested : pb::IMessage<Nested>, pb::IBufferMessage {
+      public sealed partial class Nested : pb::IMessage<Nested>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<Nested> _parser = new pb::MessageParser<Nested>(() => new Nested());
         private pb::UnknownFieldSet _unknownFields;
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2267,9 +2579,29 @@ namespace UnitTest.Issues.TestProtos {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                X = input.ReadInt32();
+                break;
+              }
+              case 16: {
+                Y = input.ReadInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -2289,6 +2621,7 @@ namespace UnitTest.Issues.TestProtos {
             }
           }
         }
+        #endif
 
       }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestProto3Optional.cs

@@ -67,7 +67,11 @@ namespace ProtobufUnittest {
 
   }
   #region Messages
-  public sealed partial class TestProto3Optional : pb::IMessage<TestProto3Optional>, pb::IBufferMessage {
+  public sealed partial class TestProto3Optional : pb::IMessage<TestProto3Optional>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestProto3Optional> _parser = new pb::MessageParser<TestProto3Optional>(() => new TestProto3Optional());
     private pb::UnknownFieldSet _unknownFields;
     private int _hasBits0;
@@ -858,9 +862,111 @@ namespace ProtobufUnittest {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            OptionalInt32 = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            OptionalInt64 = input.ReadInt64();
+            break;
+          }
+          case 24: {
+            OptionalUint32 = input.ReadUInt32();
+            break;
+          }
+          case 32: {
+            OptionalUint64 = input.ReadUInt64();
+            break;
+          }
+          case 40: {
+            OptionalSint32 = input.ReadSInt32();
+            break;
+          }
+          case 48: {
+            OptionalSint64 = input.ReadSInt64();
+            break;
+          }
+          case 61: {
+            OptionalFixed32 = input.ReadFixed32();
+            break;
+          }
+          case 65: {
+            OptionalFixed64 = input.ReadFixed64();
+            break;
+          }
+          case 77: {
+            OptionalSfixed32 = input.ReadSFixed32();
+            break;
+          }
+          case 81: {
+            OptionalSfixed64 = input.ReadSFixed64();
+            break;
+          }
+          case 93: {
+            OptionalFloat = input.ReadFloat();
+            break;
+          }
+          case 97: {
+            OptionalDouble = input.ReadDouble();
+            break;
+          }
+          case 104: {
+            OptionalBool = input.ReadBool();
+            break;
+          }
+          case 114: {
+            OptionalString = input.ReadString();
+            break;
+          }
+          case 122: {
+            OptionalBytes = input.ReadBytes();
+            break;
+          }
+          case 130: {
+            OptionalCord = input.ReadString();
+            break;
+          }
+          case 146: {
+            if (optionalNestedMessage_ == null) {
+              OptionalNestedMessage = new global::ProtobufUnittest.TestProto3Optional.Types.NestedMessage();
+            }
+            input.ReadMessage(OptionalNestedMessage);
+            break;
+          }
+          case 154: {
+            if (lazyNestedMessage_ == null) {
+              LazyNestedMessage = new global::ProtobufUnittest.TestProto3Optional.Types.NestedMessage();
+            }
+            input.ReadMessage(LazyNestedMessage);
+            break;
+          }
+          case 168: {
+            OptionalNestedEnum = (global::ProtobufUnittest.TestProto3Optional.Types.NestedEnum) input.ReadEnum();
+            break;
+          }
+          case 176: {
+            SingularInt32 = input.ReadInt32();
+            break;
+          }
+          case 184: {
+            SingularInt64 = input.ReadInt64();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -962,6 +1068,7 @@ namespace ProtobufUnittest {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the TestProto3Optional message type.</summary>
@@ -978,7 +1085,11 @@ namespace ProtobufUnittest {
         [pbr::OriginalName("NEG")] Neg = -1,
       }
 
-      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>, pb::IBufferMessage {
+      public sealed partial class NestedMessage : pb::IMessage<NestedMessage>
+      #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+          , pb::IBufferMessage
+      #endif
+      {
         private static readonly pb::MessageParser<NestedMessage> _parser = new pb::MessageParser<NestedMessage>(() => new NestedMessage());
         private pb::UnknownFieldSet _unknownFields;
         private int _hasBits0;
@@ -1109,9 +1220,25 @@ namespace ProtobufUnittest {
 
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         public void MergeFrom(pb::CodedInputStream input) {
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
           input.ReadRawMessage(this);
+        #else
+          uint tag;
+          while ((tag = input.ReadTag()) != 0) {
+            switch(tag) {
+              default:
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+                break;
+              case 8: {
+                Bb = input.ReadInt32();
+                break;
+              }
+            }
+          }
+        #endif
         }
 
+        #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
           uint tag;
@@ -1127,6 +1254,7 @@ namespace ProtobufUnittest {
             }
           }
         }
+        #endif
 
       }
 

csharp/src/Google.Protobuf.Test.TestProtos/UnittestSelfreferentialOptions.cs

@@ -63,7 +63,11 @@ namespace UnitTest.Issues.TestProtos.SelfreferentialOptions {
   }
 
   #region Messages
-  public sealed partial class FooOptions : pb::IExtendableMessage<FooOptions>, pb::IBufferMessage {
+  public sealed partial class FooOptions : pb::IExtendableMessage<FooOptions>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<FooOptions> _parser = new pb::MessageParser<FooOptions>(() => new FooOptions());
     private pb::UnknownFieldSet _unknownFields;
     private pb::ExtensionSet<FooOptions> _extensions;
@@ -250,9 +254,31 @@ namespace UnitTest.Issues.TestProtos.SelfreferentialOptions {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            if (!pb::ExtensionSet.TryMergeFieldFrom(ref _extensions, input)) {
+              _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            }
+            break;
+          case 8: {
+            IntOpt = input.ReadInt32();
+            break;
+          }
+          case 16: {
+            Foo = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -274,6 +300,7 @@ namespace UnitTest.Issues.TestProtos.SelfreferentialOptions {
         }
       }
     }
+    #endif
 
     public TValue GetExtension<TValue>(pb::Extension<FooOptions, TValue> extension) {
       return pb::ExtensionSet.Get(ref _extensions, extension);

csharp/src/Google.Protobuf.Test.TestProtos/UnittestWellKnownTypes.cs

@@ -179,7 +179,11 @@ namespace Google.Protobuf.TestProtos {
   /// Each wrapper type is included separately, as languages
   /// map handle different wrappers in different ways.
   /// </summary>
-  public sealed partial class TestWellKnownTypes : pb::IMessage<TestWellKnownTypes>, pb::IBufferMessage {
+  public sealed partial class TestWellKnownTypes : pb::IMessage<TestWellKnownTypes>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<TestWellKnownTypes> _parser = new pb::MessageParser<TestWellKnownTypes>(() => new TestWellKnownTypes());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -784,9 +788,154 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            if (anyField_ == null) {
+              AnyField = new global::Google.Protobuf.WellKnownTypes.Any();
+            }
+            input.ReadMessage(AnyField);
+            break;
+          }
+          case 18: {
+            if (apiField_ == null) {
+              ApiField = new global::Google.Protobuf.WellKnownTypes.Api();
+            }
+            input.ReadMessage(ApiField);
+            break;
+          }
+          case 26: {
+            if (durationField_ == null) {
+              DurationField = new global::Google.Protobuf.WellKnownTypes.Duration();
+            }
+            input.ReadMessage(DurationField);
+            break;
+          }
+          case 34: {
+            if (emptyField_ == null) {
+              EmptyField = new global::Google.Protobuf.WellKnownTypes.Empty();
+            }
+            input.ReadMessage(EmptyField);
+            break;
+          }
+          case 42: {
+            if (fieldMaskField_ == null) {
+              FieldMaskField = new global::Google.Protobuf.WellKnownTypes.FieldMask();
+            }
+            input.ReadMessage(FieldMaskField);
+            break;
+          }
+          case 50: {
+            if (sourceContextField_ == null) {
+              SourceContextField = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            }
+            input.ReadMessage(SourceContextField);
+            break;
+          }
+          case 58: {
+            if (structField_ == null) {
+              StructField = new global::Google.Protobuf.WellKnownTypes.Struct();
+            }
+            input.ReadMessage(StructField);
+            break;
+          }
+          case 66: {
+            if (timestampField_ == null) {
+              TimestampField = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+            }
+            input.ReadMessage(TimestampField);
+            break;
+          }
+          case 74: {
+            if (typeField_ == null) {
+              TypeField = new global::Google.Protobuf.WellKnownTypes.Type();
+            }
+            input.ReadMessage(TypeField);
+            break;
+          }
+          case 82: {
+            double? value = _single_doubleField_codec.Read(input);
+            if (doubleField_ == null || value != 0D) {
+              DoubleField = value;
+            }
+            break;
+          }
+          case 90: {
+            float? value = _single_floatField_codec.Read(input);
+            if (floatField_ == null || value != 0F) {
+              FloatField = value;
+            }
+            break;
+          }
+          case 98: {
+            long? value = _single_int64Field_codec.Read(input);
+            if (int64Field_ == null || value != 0L) {
+              Int64Field = value;
+            }
+            break;
+          }
+          case 106: {
+            ulong? value = _single_uint64Field_codec.Read(input);
+            if (uint64Field_ == null || value != 0UL) {
+              Uint64Field = value;
+            }
+            break;
+          }
+          case 114: {
+            int? value = _single_int32Field_codec.Read(input);
+            if (int32Field_ == null || value != 0) {
+              Int32Field = value;
+            }
+            break;
+          }
+          case 122: {
+            uint? value = _single_uint32Field_codec.Read(input);
+            if (uint32Field_ == null || value != 0) {
+              Uint32Field = value;
+            }
+            break;
+          }
+          case 130: {
+            bool? value = _single_boolField_codec.Read(input);
+            if (boolField_ == null || value != false) {
+              BoolField = value;
+            }
+            break;
+          }
+          case 138: {
+            string value = _single_stringField_codec.Read(input);
+            if (stringField_ == null || value != "") {
+              StringField = value;
+            }
+            break;
+          }
+          case 146: {
+            pb::ByteString value = _single_bytesField_codec.Read(input);
+            if (bytesField_ == null || value != pb::ByteString.Empty) {
+              BytesField = value;
+            }
+            break;
+          }
+          case 154: {
+            if (valueField_ == null) {
+              ValueField = new global::Google.Protobuf.WellKnownTypes.Value();
+            }
+            input.ReadMessage(ValueField);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -931,13 +1080,18 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// A repeated field for each well-known type.
   /// </summary>
-  public sealed partial class RepeatedWellKnownTypes : pb::IMessage<RepeatedWellKnownTypes>, pb::IBufferMessage {
+  public sealed partial class RepeatedWellKnownTypes : pb::IMessage<RepeatedWellKnownTypes>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<RepeatedWellKnownTypes> _parser = new pb::MessageParser<RepeatedWellKnownTypes>(() => new RepeatedWellKnownTypes());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1317,9 +1471,93 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            anyField_.AddEntriesFrom(input, _repeated_anyField_codec);
+            break;
+          }
+          case 18: {
+            apiField_.AddEntriesFrom(input, _repeated_apiField_codec);
+            break;
+          }
+          case 26: {
+            durationField_.AddEntriesFrom(input, _repeated_durationField_codec);
+            break;
+          }
+          case 34: {
+            emptyField_.AddEntriesFrom(input, _repeated_emptyField_codec);
+            break;
+          }
+          case 42: {
+            fieldMaskField_.AddEntriesFrom(input, _repeated_fieldMaskField_codec);
+            break;
+          }
+          case 50: {
+            sourceContextField_.AddEntriesFrom(input, _repeated_sourceContextField_codec);
+            break;
+          }
+          case 58: {
+            structField_.AddEntriesFrom(input, _repeated_structField_codec);
+            break;
+          }
+          case 66: {
+            timestampField_.AddEntriesFrom(input, _repeated_timestampField_codec);
+            break;
+          }
+          case 74: {
+            typeField_.AddEntriesFrom(input, _repeated_typeField_codec);
+            break;
+          }
+          case 82: {
+            doubleField_.AddEntriesFrom(input, _repeated_doubleField_codec);
+            break;
+          }
+          case 90: {
+            floatField_.AddEntriesFrom(input, _repeated_floatField_codec);
+            break;
+          }
+          case 98: {
+            int64Field_.AddEntriesFrom(input, _repeated_int64Field_codec);
+            break;
+          }
+          case 106: {
+            uint64Field_.AddEntriesFrom(input, _repeated_uint64Field_codec);
+            break;
+          }
+          case 114: {
+            int32Field_.AddEntriesFrom(input, _repeated_int32Field_codec);
+            break;
+          }
+          case 122: {
+            uint32Field_.AddEntriesFrom(input, _repeated_uint32Field_codec);
+            break;
+          }
+          case 130: {
+            boolField_.AddEntriesFrom(input, _repeated_boolField_codec);
+            break;
+          }
+          case 138: {
+            stringField_.AddEntriesFrom(input, _repeated_stringField_codec);
+            break;
+          }
+          case 146: {
+            bytesField_.AddEntriesFrom(input, _repeated_bytesField_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1403,10 +1641,15 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
-  public sealed partial class OneofWellKnownTypes : pb::IMessage<OneofWellKnownTypes>, pb::IBufferMessage {
+  public sealed partial class OneofWellKnownTypes : pb::IMessage<OneofWellKnownTypes>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<OneofWellKnownTypes> _parser = new pb::MessageParser<OneofWellKnownTypes>(() => new OneofWellKnownTypes());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2033,9 +2276,138 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            global::Google.Protobuf.WellKnownTypes.Any subBuilder = new global::Google.Protobuf.WellKnownTypes.Any();
+            if (oneofFieldCase_ == OneofFieldOneofCase.AnyField) {
+              subBuilder.MergeFrom(AnyField);
+            }
+            input.ReadMessage(subBuilder);
+            AnyField = subBuilder;
+            break;
+          }
+          case 18: {
+            global::Google.Protobuf.WellKnownTypes.Api subBuilder = new global::Google.Protobuf.WellKnownTypes.Api();
+            if (oneofFieldCase_ == OneofFieldOneofCase.ApiField) {
+              subBuilder.MergeFrom(ApiField);
+            }
+            input.ReadMessage(subBuilder);
+            ApiField = subBuilder;
+            break;
+          }
+          case 26: {
+            global::Google.Protobuf.WellKnownTypes.Duration subBuilder = new global::Google.Protobuf.WellKnownTypes.Duration();
+            if (oneofFieldCase_ == OneofFieldOneofCase.DurationField) {
+              subBuilder.MergeFrom(DurationField);
+            }
+            input.ReadMessage(subBuilder);
+            DurationField = subBuilder;
+            break;
+          }
+          case 34: {
+            global::Google.Protobuf.WellKnownTypes.Empty subBuilder = new global::Google.Protobuf.WellKnownTypes.Empty();
+            if (oneofFieldCase_ == OneofFieldOneofCase.EmptyField) {
+              subBuilder.MergeFrom(EmptyField);
+            }
+            input.ReadMessage(subBuilder);
+            EmptyField = subBuilder;
+            break;
+          }
+          case 42: {
+            global::Google.Protobuf.WellKnownTypes.FieldMask subBuilder = new global::Google.Protobuf.WellKnownTypes.FieldMask();
+            if (oneofFieldCase_ == OneofFieldOneofCase.FieldMaskField) {
+              subBuilder.MergeFrom(FieldMaskField);
+            }
+            input.ReadMessage(subBuilder);
+            FieldMaskField = subBuilder;
+            break;
+          }
+          case 50: {
+            global::Google.Protobuf.WellKnownTypes.SourceContext subBuilder = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            if (oneofFieldCase_ == OneofFieldOneofCase.SourceContextField) {
+              subBuilder.MergeFrom(SourceContextField);
+            }
+            input.ReadMessage(subBuilder);
+            SourceContextField = subBuilder;
+            break;
+          }
+          case 58: {
+            global::Google.Protobuf.WellKnownTypes.Struct subBuilder = new global::Google.Protobuf.WellKnownTypes.Struct();
+            if (oneofFieldCase_ == OneofFieldOneofCase.StructField) {
+              subBuilder.MergeFrom(StructField);
+            }
+            input.ReadMessage(subBuilder);
+            StructField = subBuilder;
+            break;
+          }
+          case 66: {
+            global::Google.Protobuf.WellKnownTypes.Timestamp subBuilder = new global::Google.Protobuf.WellKnownTypes.Timestamp();
+            if (oneofFieldCase_ == OneofFieldOneofCase.TimestampField) {
+              subBuilder.MergeFrom(TimestampField);
+            }
+            input.ReadMessage(subBuilder);
+            TimestampField = subBuilder;
+            break;
+          }
+          case 74: {
+            global::Google.Protobuf.WellKnownTypes.Type subBuilder = new global::Google.Protobuf.WellKnownTypes.Type();
+            if (oneofFieldCase_ == OneofFieldOneofCase.TypeField) {
+              subBuilder.MergeFrom(TypeField);
+            }
+            input.ReadMessage(subBuilder);
+            TypeField = subBuilder;
+            break;
+          }
+          case 82: {
+            DoubleField = _oneof_doubleField_codec.Read(input);
+            break;
+          }
+          case 90: {
+            FloatField = _oneof_floatField_codec.Read(input);
+            break;
+          }
+          case 98: {
+            Int64Field = _oneof_int64Field_codec.Read(input);
+            break;
+          }
+          case 106: {
+            Uint64Field = _oneof_uint64Field_codec.Read(input);
+            break;
+          }
+          case 114: {
+            Int32Field = _oneof_int32Field_codec.Read(input);
+            break;
+          }
+          case 122: {
+            Uint32Field = _oneof_uint32Field_codec.Read(input);
+            break;
+          }
+          case 130: {
+            BoolField = _oneof_boolField_codec.Read(input);
+            break;
+          }
+          case 138: {
+            StringField = _oneof_stringField_codec.Read(input);
+            break;
+          }
+          case 146: {
+            BytesField = _oneof_bytesField_codec.Read(input);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2164,6 +2536,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 
@@ -2172,7 +2545,11 @@ namespace Google.Protobuf.TestProtos {
   /// need to worry about the value part of the map being the
   /// well-known types, as messages can't be map keys.
   /// </summary>
-  public sealed partial class MapWellKnownTypes : pb::IMessage<MapWellKnownTypes>, pb::IBufferMessage {
+  public sealed partial class MapWellKnownTypes : pb::IMessage<MapWellKnownTypes>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<MapWellKnownTypes> _parser = new pb::MessageParser<MapWellKnownTypes>(() => new MapWellKnownTypes());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -2549,9 +2926,93 @@ namespace Google.Protobuf.TestProtos {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            anyField_.AddEntriesFrom(input, _map_anyField_codec);
+            break;
+          }
+          case 18: {
+            apiField_.AddEntriesFrom(input, _map_apiField_codec);
+            break;
+          }
+          case 26: {
+            durationField_.AddEntriesFrom(input, _map_durationField_codec);
+            break;
+          }
+          case 34: {
+            emptyField_.AddEntriesFrom(input, _map_emptyField_codec);
+            break;
+          }
+          case 42: {
+            fieldMaskField_.AddEntriesFrom(input, _map_fieldMaskField_codec);
+            break;
+          }
+          case 50: {
+            sourceContextField_.AddEntriesFrom(input, _map_sourceContextField_codec);
+            break;
+          }
+          case 58: {
+            structField_.AddEntriesFrom(input, _map_structField_codec);
+            break;
+          }
+          case 66: {
+            timestampField_.AddEntriesFrom(input, _map_timestampField_codec);
+            break;
+          }
+          case 74: {
+            typeField_.AddEntriesFrom(input, _map_typeField_codec);
+            break;
+          }
+          case 82: {
+            doubleField_.AddEntriesFrom(input, _map_doubleField_codec);
+            break;
+          }
+          case 90: {
+            floatField_.AddEntriesFrom(input, _map_floatField_codec);
+            break;
+          }
+          case 98: {
+            int64Field_.AddEntriesFrom(input, _map_int64Field_codec);
+            break;
+          }
+          case 106: {
+            uint64Field_.AddEntriesFrom(input, _map_uint64Field_codec);
+            break;
+          }
+          case 114: {
+            int32Field_.AddEntriesFrom(input, _map_int32Field_codec);
+            break;
+          }
+          case 122: {
+            uint32Field_.AddEntriesFrom(input, _map_uint32Field_codec);
+            break;
+          }
+          case 130: {
+            boolField_.AddEntriesFrom(input, _map_boolField_codec);
+            break;
+          }
+          case 138: {
+            stringField_.AddEntriesFrom(input, _map_stringField_codec);
+            break;
+          }
+          case 146: {
+            bytesField_.AddEntriesFrom(input, _map_bytesField_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -2635,6 +3096,7 @@ namespace Google.Protobuf.TestProtos {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf.Test/ByteStringTest.cs

@@ -233,5 +233,21 @@ namespace Google.Protobuf
             ByteString b2 = ByteString.CopyFrom(200, 1, 2, 3, 4);
             Assert.AreNotEqual(b1.GetHashCode(), b2.GetHashCode());
         }
+
+        [Test]
+        public void GetContentsAsReadOnlySpan()
+        {
+            var byteString = ByteString.CopyFrom(1, 2, 3, 4, 5);
+            var copied = byteString.Span.ToArray();
+            CollectionAssert.AreEqual(byteString, copied);
+        }
+
+        [Test]
+        public void GetContentsAsReadOnlyMemory()
+        {
+            var byteString = ByteString.CopyFrom(1, 2, 3, 4, 5);
+            var copied = byteString.Memory.ToArray();
+            CollectionAssert.AreEqual(byteString, copied);
+        }
     }
 }

csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs

@@ -595,6 +595,95 @@ namespace Google.Protobuf.Collections
             Assert.AreEqual(((SampleEnum)(-5)), values[5]);
         }
 
+        [Test]
+        public void TestPackedRepeatedFieldCollectionNonDivisibleLength()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var codec = FieldCodec.ForFixed32(tag);
+            var stream = new MemoryStream();
+            var output = new CodedOutputStream(stream);
+            output.WriteTag(tag);
+            output.WriteString("A long string");
+            output.WriteTag(codec.Tag);
+            output.WriteRawVarint32((uint)codec.FixedSize - 1); // Length not divisible by FixedSize
+            output.WriteFixed32(uint.MaxValue);
+            output.Flush();
+            stream.Position = 0;
+
+            var input = new CodedInputStream(stream);
+            input.ReadTag();
+            input.ReadString();
+            input.ReadTag();
+            var field = new RepeatedField<uint>();
+            Assert.Throws<InvalidProtocolBufferException>(() => field.AddEntriesFrom(input, codec));
+
+            // Collection was not pre-initialized
+            Assert.AreEqual(0, field.Count);
+        }
+
+        [Test]
+        public void TestPackedRepeatedFieldCollectionNotAllocatedWhenLengthExceedsBuffer()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var codec = FieldCodec.ForFixed32(tag);
+            var stream = new MemoryStream();
+            var output = new CodedOutputStream(stream);
+            output.WriteTag(tag);
+            output.WriteString("A long string");
+            output.WriteTag(codec.Tag);
+            output.WriteRawVarint32((uint)codec.FixedSize);
+            // Note that there is no content for the packed field.
+            // The field length exceeds the remaining length of content.
+            output.Flush();
+            stream.Position = 0;
+
+            var input = new CodedInputStream(stream);
+            input.ReadTag();
+            input.ReadString();
+            input.ReadTag();
+            var field = new RepeatedField<uint>();
+            Assert.Throws<InvalidProtocolBufferException>(() => field.AddEntriesFrom(input, codec));
+
+            // Collection was not pre-initialized
+            Assert.AreEqual(0, field.Count);
+        }
+
+        [Test]
+        public void TestPackedRepeatedFieldCollectionNotAllocatedWhenLengthExceedsRemainingData()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var codec = FieldCodec.ForFixed32(tag);
+            var stream = new MemoryStream();
+            var output = new CodedOutputStream(stream);
+            output.WriteTag(tag);
+            output.WriteString("A long string");
+            output.WriteTag(codec.Tag);
+            output.WriteRawVarint32((uint)codec.FixedSize);
+            // Note that there is no content for the packed field.
+            // The field length exceeds the remaining length of the buffer.
+            output.Flush();
+            stream.Position = 0;
+
+            var sequence = ReadOnlySequenceFactory.CreateWithContent(stream.ToArray());
+            ParseContext.Initialize(sequence, out ParseContext ctx);
+
+            ctx.ReadTag();
+            ctx.ReadString();
+            ctx.ReadTag();
+            var field = new RepeatedField<uint>();
+            try
+            {
+                field.AddEntriesFrom(ref ctx, codec);
+                Assert.Fail();
+            }
+            catch (InvalidProtocolBufferException)
+            {
+            }
+
+            // Collection was not pre-initialized
+            Assert.AreEqual(0, field.Count);
+        }
+
         // Fairly perfunctory tests for the non-generic IList implementation
         [Test]
         public void IList_Indexer()

csharp/src/Google.Protobuf.Test/JsonFormatterTest.cs

@@ -40,6 +40,7 @@ using Google.Protobuf.Reflection;
 using static Google.Protobuf.JsonParserTest; // For WrapInQuotes
 using System.IO;
 using Google.Protobuf.Collections;
+using ProtobufUnittest;
 
 namespace Google.Protobuf
 {
@@ -153,6 +154,48 @@ namespace Google.Protobuf
             AssertJson(expectedText, actualText);
         }
 
+        [Test]
+        public void WithFormatDefaultValues_DoesNotAffectMessageFields()
+        {
+            var message = new TestAllTypes();
+            var formatter = new JsonFormatter(JsonFormatter.Settings.Default.WithFormatDefaultValues(true));
+            var json = formatter.Format(message);
+            Assert.IsFalse(json.Contains("\"singleNestedMessage\""));
+            Assert.IsFalse(json.Contains("\"singleForeignMessage\""));
+            Assert.IsFalse(json.Contains("\"singleImportMessage\""));
+        }
+
+        [Test]
+        public void WithFormatDefaultValues_DoesNotAffectProto3OptionalFields()
+        {
+            var message = new TestProto3Optional();
+            message.OptionalInt32 = 0;
+            var formatter = new JsonFormatter(JsonFormatter.Settings.Default.WithFormatDefaultValues(true));
+            var json = formatter.Format(message);
+            // The non-optional proto3 fields are formatted, as is the optional-but-specified field.
+            AssertJson("{ 'optionalInt32': 0, 'singularInt32': 0, 'singularInt64': '0' }", json);
+        }
+
+        [Test]
+        public void WithFormatDefaultValues_DoesNotAffectProto2Fields()
+        {
+            var message = new TestProtos.Proto2.ForeignMessage();
+            message.C = 0;
+            var formatter = new JsonFormatter(JsonFormatter.Settings.Default.WithFormatDefaultValues(true));
+            var json = formatter.Format(message);
+            // The specified field is formatted, but the non-specified field (d) is not.
+            AssertJson("{ 'c': 0 }", json);
+        }
+
+        [Test]
+        public void WithFormatDefaultValues_DoesNotAffectOneofFields()
+        {
+            var message = new TestOneof();
+            var formatter = new JsonFormatter(JsonFormatter.Settings.Default.WithFormatDefaultValues(true));
+            var json = formatter.Format(message);
+            AssertJson("{ }", json);
+        }
+
         [Test]
         public void RepeatedField()
         {
@@ -313,14 +356,16 @@ namespace Google.Protobuf
         }
 
         [Test]
-        public void WrapperFormatting_IncludeNull()
+        public void WrapperFormatting_FormatDefaultValuesDoesNotFormatNull()
         {
             // The actual JSON here is very large because there are lots of fields. Just test a couple of them.
             var message = new TestWellKnownTypes { Int32Field = 10 };
             var formatter = new JsonFormatter(JsonFormatter.Settings.Default.WithFormatDefaultValues(true));
             var actualJson = formatter.Format(message);
-            Assert.IsTrue(actualJson.Contains("\"int64Field\": null"));
-            Assert.IsFalse(actualJson.Contains("\"int32Field\": null"));
+            // This *used* to include "int64Field": null, but that was a bug.
+            // WithDefaultValues should not affect message fields, including wrapper types.
+            Assert.IsFalse(actualJson.Contains("\"int64Field\": null"));
+            Assert.IsTrue(actualJson.Contains("\"int32Field\": 10"));
         }
 
         [Test]
@@ -602,6 +647,13 @@ namespace Google.Protobuf
             AssertWriteValue(value, "[ 1, 2, 3 ]");
         }
 
+        [Test]
+        public void Proto2_DefaultValuesWritten()
+        {
+            var value = new ProtobufTestMessages.Proto2.TestAllTypesProto2() { FieldName13 = 0 };
+            AssertWriteValue(value, "{ 'FieldName13': 0 }");
+        }
+
         private static void AssertWriteValue(object value, string expectedJson)
         {
             var writer = new StringWriter();

csharp/src/Google.Protobuf.Test/JsonParserTest.cs

@@ -34,6 +34,7 @@ using Google.Protobuf.Reflection;
 using Google.Protobuf.TestProtos;
 using Google.Protobuf.WellKnownTypes;
 using NUnit.Framework;
+using ProtobufTestMessages.Proto2;
 using System;
 
 namespace Google.Protobuf
@@ -949,6 +950,16 @@ namespace Google.Protobuf
             Assert.Throws<InvalidProtocolBufferException>(() => TestAllTypes.Parser.ParseJson(json));
         }
 
+        [Test]
+        public void Proto2_DefaultValuesPreserved()
+        {
+            string json = "{ \"FieldName13\": 0 }";
+            var parsed = TestAllTypesProto2.Parser.ParseJson(json);
+            Assert.False(parsed.HasFieldName10);
+            Assert.True(parsed.HasFieldName13);
+            Assert.AreEqual(0, parsed.FieldName13);
+        }
+
         [Test]
         [TestCase("5")]
         [TestCase("\"text\"")]

csharp/src/Google.Protobuf.Test/ReadOnlySequenceFactory.cs

@@ -50,9 +50,9 @@ namespace Google.Protobuf
             while (currentIndex < data.Length)
             {
                 var segment = new List<byte>();
-                for (; currentIndex < Math.Min(currentIndex + segmentSize, data.Length); currentIndex++)
+                while (segment.Count < segmentSize && currentIndex < data.Length)
                 {
-                    segment.Add(data[currentIndex]);
+                    segment.Add(data[currentIndex++]);
                 }
                 segments.Add(segment.ToArray());
                 segments.Add(new byte[0]);

csharp/src/Google.Protobuf.Test/RefStructCompatibilityTest.cs

@@ -0,0 +1,119 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using NUnit.Framework;
+using System.Diagnostics;
+using System;
+using System.Reflection;
+using System.IO;
+
+namespace Google.Protobuf
+{
+    public class RefStructCompatibilityTest
+    {
+        /// <summary>
+        /// Checks that the generated code can be compiler with an old C# compiler.
+        /// The reason why this test is needed is that even though dotnet SDK projects allow to set LangVersion,
+        /// this setting doesn't accurately simulate compilation with an actual old pre-roslyn C# compiler.
+        /// For instance, the "ref struct" types are only supported by C# 7.2 and higher, but even if
+        /// LangVersion is set low, the roslyn compiler still understands the concept of ref struct
+        /// and silently accepts them. Therefore we try to build the generated code with an actual old C# compiler
+        /// to be able to catch these sort of compatibility problems.
+        /// </summary>
+        [Test]
+        public void GeneratedCodeCompilesWithOldCsharpCompiler()
+        {
+            if (Environment.OSVersion.Platform != PlatformID.Win32NT)
+            {
+                // This tests needs old C# compiler which is only available on Windows. Skipping it on all other platforms.
+                return;
+            }
+
+            var currentAssemblyDir = Path.GetDirectoryName(typeof(RefStructCompatibilityTest).GetTypeInfo().Assembly.Location);
+            var testProtosProjectDir = Path.GetFullPath(Path.Combine(currentAssemblyDir, "..", "..", "..", "..", "Google.Protobuf.Test.TestProtos"));
+            var testProtosOutputDir = (currentAssemblyDir.Contains("bin/Debug/") || currentAssemblyDir.Contains("bin\\Debug\\")) ? "bin\\Debug\\net45" : "bin\\Release\\net45";
+
+            // If "ref struct" types are used in the generated code, compilation with an old compiler will fail with the following error:
+            // "XYZ is obsolete: 'Types with embedded references are not supported in this version of your compiler.'"
+            // We build the code with GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE to avoid the use of ref struct in the generated code.
+            var compatibilityFlag = "-define:GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE";
+            var sources = "*.cs";  // the generated sources from the TestProtos project
+            var args = $"-langversion:3 -target:library {compatibilityFlag} -reference:{testProtosOutputDir}\\Google.Protobuf.dll -out:{testProtosOutputDir}\\TestProtos.RefStructCompatibilityTest.OldCompiler.dll {sources}";
+            RunOldCsharpCompilerAndCheckSuccess(args, testProtosProjectDir);
+        }
+
+        /// <summary>
+        /// Invoke an old C# compiler in a subprocess and check it finished successful.
+        /// </summary>
+        /// <param name="args"></param>
+        /// <param name="workingDirectory"></param>
+        private void RunOldCsharpCompilerAndCheckSuccess(string args, string workingDirectory)
+        {  
+            using (var process = new Process())
+            {
+                // Get the path to the old C# 5 compiler from .NET framework. This approach is not 100% reliable, but works on most machines.
+                // Alternative way of getting the framework path is System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory()
+                // but it only works with the net45 target.
+                var oldCsharpCompilerPath = Path.Combine(Environment.GetEnvironmentVariable("WINDIR"), "Microsoft.NET", "Framework", "v4.0.30319", "csc.exe");
+                process.StartInfo.FileName = oldCsharpCompilerPath;
+                process.StartInfo.RedirectStandardOutput = true;
+                process.StartInfo.RedirectStandardError = true;
+                process.StartInfo.UseShellExecute = false;
+                process.StartInfo.Arguments = args;
+                process.StartInfo.WorkingDirectory = workingDirectory;
+
+                process.OutputDataReceived += (sender, e) =>
+                {
+                    if (e.Data != null)
+                    {
+                        Console.WriteLine(e.Data);
+                    }
+                };
+                process.ErrorDataReceived += (sender, e) =>
+                {
+                    if (e.Data != null)
+                    {
+                        Console.WriteLine(e.Data);
+                    }
+                };
+
+                process.Start();
+
+                process.BeginErrorReadLine();
+                process.BeginOutputReadLine();
+
+                process.WaitForExit();
+                Assert.AreEqual(0, process.ExitCode);
+            }
+        }
+    }
+}

csharp/src/Google.Protobuf/ByteString.cs

@@ -34,6 +34,7 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
+using System.Security;
 using System.Text;
 #if !NET35
 using System.Threading;
@@ -115,13 +116,27 @@ namespace Google.Protobuf
         /// Provides read-only access to the data of this <see cref="ByteString"/>.
         /// No data is copied so this is the most efficient way of accessing.
         /// </summary>
-        public ReadOnlySpan<byte> Span => new ReadOnlySpan<byte>(bytes);
+        public ReadOnlySpan<byte> Span
+        {
+            [SecuritySafeCritical]
+            get
+            {
+                return new ReadOnlySpan<byte>(bytes);
+            }
+        }
 
         /// <summary>
         /// Provides read-only access to the data of this <see cref="ByteString"/>.
         /// No data is copied so this is the most efficient way of accessing.
         /// </summary>
-        public ReadOnlyMemory<byte> Memory => new ReadOnlyMemory<byte>(bytes);
+        public ReadOnlyMemory<byte> Memory
+        {
+            [SecuritySafeCritical]
+            get
+            {
+                return new ReadOnlyMemory<byte>(bytes);
+            }
+        }
 #endif
 
         /// <summary>

csharp/src/Google.Protobuf/Collections/RepeatedField.cs

@@ -35,6 +35,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Security;
+using System.Threading;
 
 namespace Google.Protobuf.Collections
 {
@@ -126,9 +127,31 @@ namespace Google.Protobuf.Collections
                 if (length > 0)
                 {
                     int oldLimit = SegmentedBufferHelper.PushLimit(ref ctx.state, length);
-                    while (!SegmentedBufferHelper.IsReachedLimit(ref ctx.state))
+
+                    // If the content is fixed size then we can calculate the length
+                    // of the repeated field and pre-initialize the underlying collection.
+                    //
+                    // Check that the supplied length doesn't exceed the underlying buffer.
+                    // That prevents a malicious length from initializing a very large collection.
+                    if (codec.FixedSize > 0 && length % codec.FixedSize == 0 && IsDataAvailable(ref ctx, length))
+                    {
+                        EnsureSize(count + (length / codec.FixedSize));
+
+                        while (!SegmentedBufferHelper.IsReachedLimit(ref ctx.state))
+                        {
+                            // Only FieldCodecs with a fixed size can reach here, and they are all known
+                            // types that don't allow the user to specify a custom reader action.
+                            // reader action will never return null.
+                            array[count++] = reader(ref ctx);
+                        }
+                    }
+                    else
                     {
-                        Add(reader(ref ctx));
+                        // Content is variable size so add until we reach the limit.
+                        while (!SegmentedBufferHelper.IsReachedLimit(ref ctx.state))
+                        {
+                            Add(reader(ref ctx));
+                        }
                     }
                     SegmentedBufferHelper.PopLimit(ref ctx.state, oldLimit);
                 }
@@ -144,6 +167,24 @@ namespace Google.Protobuf.Collections
             }
         }
 
+        private bool IsDataAvailable(ref ParseContext ctx, int size)
+        {
+            // Data fits in remaining buffer
+            if (size <= ctx.state.bufferSize - ctx.state.bufferPos)
+            {
+                return true;
+            }
+
+            // Data fits in remaining source data.
+            // Note that this will never be true when reading from a stream as the total length is unknown.
+            if (size < ctx.state.segmentedBufferHelper.TotalLength - ctx.state.totalBytesRetired - ctx.state.bufferPos)
+            {
+                return true;
+            }
+
+            return false;
+        }
+
         /// <summary>
         /// Calculates the size of this collection based on the given codec.
         /// </summary>

csharp/src/Google.Protobuf/Google.Protobuf.csproj

@@ -5,6 +5,7 @@
     <Copyright>Copyright 2015, Google Inc.</Copyright>
     <AssemblyTitle>Google Protocol Buffers</AssemblyTitle>
     <VersionPrefix>3.12.2</VersionPrefix>
+    <VersionPrefix>3.12.3</VersionPrefix>
     <!-- C# 7.2 is required for Span/BufferWriter/ReadOnlySequence -->
     <LangVersion>7.2</LangVersion>
     <Authors>Google Inc.</Authors>

csharp/src/Google.Protobuf/JsonFormatter.cs

@@ -221,19 +221,12 @@ namespace Google.Protobuf
             foreach (var field in fields.InFieldNumberOrder())
             {
                 var accessor = field.Accessor;
-                if (field.ContainingOneof != null && field.ContainingOneof.Accessor.GetCaseFieldDescriptor(message) != field)
-                {
-                    continue;
-                }
-                // Omit default values unless we're asked to format them, or they're oneofs (where the default
-                // value is still formatted regardless, because that's how we preserve the oneof case).
-                object value = accessor.GetValue(message);
-                if (field.ContainingOneof == null && !settings.FormatDefaultValues && IsDefaultValue(accessor, value))
+                var value = accessor.GetValue(message);
+                if (!ShouldFormatFieldValue(message, field, value))
                 {
                     continue;
                 }
 
-                // Okay, all tests complete: let's write the field value...
                 if (!first)
                 {
                     writer.Write(PropertySeparator);
@@ -248,6 +241,18 @@ namespace Google.Protobuf
             return !first;
         }
 
+        /// <summary>
+        /// Determines whether or not a field value should be serialized according to the field,
+        /// its value in the message, and the settings of this formatter.
+        /// </summary>
+        private bool ShouldFormatFieldValue(IMessage message, FieldDescriptor field, object value) =>
+            field.HasPresence
+            // Fields that support presence *just* use that
+            ? field.Accessor.HasValue(message)
+            // Otherwise, format if either we've been asked to format default values, or if it's
+            // not a default value anyway.
+            : settings.FormatDefaultValues || !IsDefaultValue(field, value);
+
         // Converted from java/core/src/main/java/com/google/protobuf/Descriptors.java
         internal static string ToJsonName(string name)
         {
@@ -295,19 +300,19 @@ namespace Google.Protobuf
             writer.Write("null");
         }
 
-        private static bool IsDefaultValue(IFieldAccessor accessor, object value)
+        private static bool IsDefaultValue(FieldDescriptor descriptor, object value)
         {
-            if (accessor.Descriptor.IsMap)
+            if (descriptor.IsMap)
             {
                 IDictionary dictionary = (IDictionary) value;
                 return dictionary.Count == 0;
             }
-            if (accessor.Descriptor.IsRepeated)
+            if (descriptor.IsRepeated)
             {
                 IList list = (IList) value;
                 return list.Count == 0;
             }
-            switch (accessor.Descriptor.FieldType)
+            switch (descriptor.FieldType)
             {
                 case FieldType.Bool:
                     return (bool) value == false;
@@ -793,8 +798,10 @@ namespace Google.Protobuf
             }
 
             /// <summary>
-            /// Whether fields whose values are the default for the field type (e.g. 0 for integers)
-            /// should be formatted (true) or omitted (false).
+            /// Whether fields which would otherwise not be included in the formatted data
+            /// should be formatted even when the value is not present, or has the default value.
+            /// This option only affects fields which don't support "presence" (e.g.
+            /// singular non-optional proto3 primitive fields).
             /// </summary>
             public bool FormatDefaultValues { get; }
 

csharp/src/Google.Protobuf/WellKnownTypes/Any.cs

@@ -119,7 +119,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///       "value": "1.212s"
   ///     }
   /// </summary>
-  public sealed partial class Any : pb::IMessage<Any>, pb::IBufferMessage {
+  public sealed partial class Any : pb::IMessage<Any>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Any> _parser = new pb::MessageParser<Any>(() => new Any());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -288,9 +292,29 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            TypeUrl = input.ReadString();
+            break;
+          }
+          case 18: {
+            Value = input.ReadBytes();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -310,6 +334,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Api.cs

@@ -64,7 +64,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// this message itself. See https://cloud.google.com/apis/design/glossary for
   /// detailed terminology.
   /// </summary>
-  public sealed partial class Api : pb::IMessage<Api>, pb::IBufferMessage {
+  public sealed partial class Api : pb::IMessage<Api>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Api> _parser = new pb::MessageParser<Api>(() => new Api());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -341,9 +345,52 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            methods_.AddEntriesFrom(input, _repeated_methods_codec);
+            break;
+          }
+          case 26: {
+            options_.AddEntriesFrom(input, _repeated_options_codec);
+            break;
+          }
+          case 34: {
+            Version = input.ReadString();
+            break;
+          }
+          case 42: {
+            if (sourceContext_ == null) {
+              SourceContext = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            }
+            input.ReadMessage(SourceContext);
+            break;
+          }
+          case 50: {
+            mixins_.AddEntriesFrom(input, _repeated_mixins_codec);
+            break;
+          }
+          case 56: {
+            Syntax = (global::Google.Protobuf.WellKnownTypes.Syntax) input.ReadEnum();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -386,13 +433,18 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Method represents a method of an API interface.
   /// </summary>
-  public sealed partial class Method : pb::IMessage<Method>, pb::IBufferMessage {
+  public sealed partial class Method : pb::IMessage<Method>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Method> _parser = new pb::MessageParser<Method>(() => new Method());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -662,9 +714,49 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            RequestTypeUrl = input.ReadString();
+            break;
+          }
+          case 24: {
+            RequestStreaming = input.ReadBool();
+            break;
+          }
+          case 34: {
+            ResponseTypeUrl = input.ReadString();
+            break;
+          }
+          case 40: {
+            ResponseStreaming = input.ReadBool();
+            break;
+          }
+          case 50: {
+            options_.AddEntriesFrom(input, _repeated_options_codec);
+            break;
+          }
+          case 56: {
+            Syntax = (global::Google.Protobuf.WellKnownTypes.Syntax) input.ReadEnum();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -704,6 +796,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -787,7 +880,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///       ...
   ///     }
   /// </summary>
-  public sealed partial class Mixin : pb::IMessage<Mixin>, pb::IBufferMessage {
+  public sealed partial class Mixin : pb::IMessage<Mixin>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Mixin> _parser = new pb::MessageParser<Mixin>(() => new Mixin());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -931,9 +1028,29 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            Root = input.ReadString();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -953,6 +1070,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs

@@ -100,7 +100,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// be expressed in JSON format as "3.000000001s", and 3 seconds and 1
   /// microsecond should be expressed in JSON format as "3.000001s".
   /// </summary>
-  public sealed partial class Duration : pb::IMessage<Duration>, pb::IBufferMessage {
+  public sealed partial class Duration : pb::IMessage<Duration>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Duration> _parser = new pb::MessageParser<Duration>(() => new Duration());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -250,9 +254,29 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Seconds = input.ReadInt64();
+            break;
+          }
+          case 16: {
+            Nanos = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -272,6 +296,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs

@@ -50,7 +50,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `Empty` is empty JSON object `{}`.
   /// </summary>
-  public sealed partial class Empty : pb::IMessage<Empty>, pb::IBufferMessage {
+  public sealed partial class Empty : pb::IMessage<Empty>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Empty> _parser = new pb::MessageParser<Empty>(() => new Empty());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -139,9 +143,21 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -153,6 +169,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs

@@ -240,7 +240,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// request should verify the included field paths, and return an
   /// `INVALID_ARGUMENT` error if any path is unmappable.
   /// </summary>
-  public sealed partial class FieldMask : pb::IMessage<FieldMask>, pb::IBufferMessage {
+  public sealed partial class FieldMask : pb::IMessage<FieldMask>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<FieldMask> _parser = new pb::MessageParser<FieldMask>(() => new FieldMask());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -348,9 +352,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            paths_.AddEntriesFrom(input, _repeated_paths_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -366,6 +386,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs

@@ -44,7 +44,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// `SourceContext` represents information about the source of a
   /// protobuf element, like the file in which it is defined.
   /// </summary>
-  public sealed partial class SourceContext : pb::IMessage<SourceContext>, pb::IBufferMessage {
+  public sealed partial class SourceContext : pb::IMessage<SourceContext>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<SourceContext> _parser = new pb::MessageParser<SourceContext>(() => new SourceContext());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -161,9 +165,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            FileName = input.ReadString();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -179,6 +199,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs

@@ -77,7 +77,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `Struct` is JSON object.
   /// </summary>
-  public sealed partial class Struct : pb::IMessage<Struct>, pb::IBufferMessage {
+  public sealed partial class Struct : pb::IMessage<Struct>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Struct> _parser = new pb::MessageParser<Struct>(() => new Struct());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -185,9 +189,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            fields_.AddEntriesFrom(input, _map_fields_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -203,6 +223,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -214,7 +235,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `Value` is JSON value.
   /// </summary>
-  public sealed partial class Value : pb::IMessage<Value>, pb::IBufferMessage {
+  public sealed partial class Value : pb::IMessage<Value>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Value> _parser = new pb::MessageParser<Value>(() => new Value());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -514,9 +539,56 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            kind_ = input.ReadEnum();
+            kindCase_ = KindOneofCase.NullValue;
+            break;
+          }
+          case 17: {
+            NumberValue = input.ReadDouble();
+            break;
+          }
+          case 26: {
+            StringValue = input.ReadString();
+            break;
+          }
+          case 32: {
+            BoolValue = input.ReadBool();
+            break;
+          }
+          case 42: {
+            global::Google.Protobuf.WellKnownTypes.Struct subBuilder = new global::Google.Protobuf.WellKnownTypes.Struct();
+            if (kindCase_ == KindOneofCase.StructValue) {
+              subBuilder.MergeFrom(StructValue);
+            }
+            input.ReadMessage(subBuilder);
+            StructValue = subBuilder;
+            break;
+          }
+          case 50: {
+            global::Google.Protobuf.WellKnownTypes.ListValue subBuilder = new global::Google.Protobuf.WellKnownTypes.ListValue();
+            if (kindCase_ == KindOneofCase.ListValue) {
+              subBuilder.MergeFrom(ListValue);
+            }
+            input.ReadMessage(subBuilder);
+            ListValue = subBuilder;
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -563,6 +635,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -571,7 +644,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `ListValue` is JSON array.
   /// </summary>
-  public sealed partial class ListValue : pb::IMessage<ListValue>, pb::IBufferMessage {
+  public sealed partial class ListValue : pb::IMessage<ListValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<ListValue> _parser = new pb::MessageParser<ListValue>(() => new ListValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -679,9 +756,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            values_.AddEntriesFrom(input, _repeated_values_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -697,6 +790,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs

@@ -123,7 +123,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// http://www.joda.org/joda-time/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateTime%2D%2D
   /// ) to obtain a formatter capable of generating timestamps in this format.
   /// </summary>
-  public sealed partial class Timestamp : pb::IMessage<Timestamp>, pb::IBufferMessage {
+  public sealed partial class Timestamp : pb::IMessage<Timestamp>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Timestamp> _parser = new pb::MessageParser<Timestamp>(() => new Timestamp());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -271,9 +275,29 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Seconds = input.ReadInt64();
+            break;
+          }
+          case 16: {
+            Nanos = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -293,6 +317,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Type.cs

@@ -94,7 +94,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// <summary>
   /// A protocol buffer message type.
   /// </summary>
-  public sealed partial class Type : pb::IMessage<Type>, pb::IBufferMessage {
+  public sealed partial class Type : pb::IMessage<Type>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Type> _parser = new pb::MessageParser<Type>(() => new Type());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -324,9 +328,48 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            fields_.AddEntriesFrom(input, _repeated_fields_codec);
+            break;
+          }
+          case 26: {
+            oneofs_.AddEntriesFrom(input, _repeated_oneofs_codec);
+            break;
+          }
+          case 34: {
+            options_.AddEntriesFrom(input, _repeated_options_codec);
+            break;
+          }
+          case 42: {
+            if (sourceContext_ == null) {
+              SourceContext = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            }
+            input.ReadMessage(SourceContext);
+            break;
+          }
+          case 48: {
+            Syntax = (global::Google.Protobuf.WellKnownTypes.Syntax) input.ReadEnum();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -365,13 +408,18 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// A single field of a message type.
   /// </summary>
-  public sealed partial class Field : pb::IMessage<Field>, pb::IBufferMessage {
+  public sealed partial class Field : pb::IMessage<Field>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Field> _parser = new pb::MessageParser<Field>(() => new Field());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -724,9 +772,61 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Kind = (global::Google.Protobuf.WellKnownTypes.Field.Types.Kind) input.ReadEnum();
+            break;
+          }
+          case 16: {
+            Cardinality = (global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality) input.ReadEnum();
+            break;
+          }
+          case 24: {
+            Number = input.ReadInt32();
+            break;
+          }
+          case 34: {
+            Name = input.ReadString();
+            break;
+          }
+          case 50: {
+            TypeUrl = input.ReadString();
+            break;
+          }
+          case 56: {
+            OneofIndex = input.ReadInt32();
+            break;
+          }
+          case 64: {
+            Packed = input.ReadBool();
+            break;
+          }
+          case 74: {
+            options_.AddEntriesFrom(input, _repeated_options_codec);
+            break;
+          }
+          case 82: {
+            JsonName = input.ReadString();
+            break;
+          }
+          case 90: {
+            DefaultValue = input.ReadString();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -778,6 +878,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
     #region Nested types
     /// <summary>Container for nested types declared in the Field message type.</summary>
@@ -895,7 +996,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// <summary>
   /// Enum type definition.
   /// </summary>
-  public sealed partial class Enum : pb::IMessage<Enum>, pb::IBufferMessage {
+  public sealed partial class Enum : pb::IMessage<Enum>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Enum> _parser = new pb::MessageParser<Enum>(() => new Enum());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1106,9 +1211,44 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            enumvalue_.AddEntriesFrom(input, _repeated_enumvalue_codec);
+            break;
+          }
+          case 26: {
+            options_.AddEntriesFrom(input, _repeated_options_codec);
+            break;
+          }
+          case 34: {
+            if (sourceContext_ == null) {
+              SourceContext = new global::Google.Protobuf.WellKnownTypes.SourceContext();
+            }
+            input.ReadMessage(SourceContext);
+            break;
+          }
+          case 40: {
+            Syntax = (global::Google.Protobuf.WellKnownTypes.Syntax) input.ReadEnum();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1143,13 +1283,18 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
   /// <summary>
   /// Enum value definition.
   /// </summary>
-  public sealed partial class EnumValue : pb::IMessage<EnumValue>, pb::IBufferMessage {
+  public sealed partial class EnumValue : pb::IMessage<EnumValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<EnumValue> _parser = new pb::MessageParser<EnumValue>(() => new EnumValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1311,9 +1456,33 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 16: {
+            Number = input.ReadInt32();
+            break;
+          }
+          case 26: {
+            options_.AddEntriesFrom(input, _repeated_options_codec);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1337,6 +1506,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -1344,7 +1514,11 @@ namespace Google.Protobuf.WellKnownTypes {
   /// A protocol buffer option, which can be attached to a message, field,
   /// enumeration, etc.
   /// </summary>
-  public sealed partial class Option : pb::IMessage<Option>, pb::IBufferMessage {
+  public sealed partial class Option : pb::IMessage<Option>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Option> _parser = new pb::MessageParser<Option>(() => new Option());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1496,9 +1670,32 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+          case 18: {
+            if (value_ == null) {
+              Value = new global::Google.Protobuf.WellKnownTypes.Any();
+            }
+            input.ReadMessage(Value);
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1521,6 +1718,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs

@@ -57,7 +57,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `DoubleValue` is JSON number.
   /// </summary>
-  public sealed partial class DoubleValue : pb::IMessage<DoubleValue>, pb::IBufferMessage {
+  public sealed partial class DoubleValue : pb::IMessage<DoubleValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<DoubleValue> _parser = new pb::MessageParser<DoubleValue>(() => new DoubleValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -173,9 +177,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 9: {
+            Value = input.ReadDouble();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -191,6 +211,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -199,7 +220,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `FloatValue` is JSON number.
   /// </summary>
-  public sealed partial class FloatValue : pb::IMessage<FloatValue>, pb::IBufferMessage {
+  public sealed partial class FloatValue : pb::IMessage<FloatValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<FloatValue> _parser = new pb::MessageParser<FloatValue>(() => new FloatValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -315,9 +340,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 13: {
+            Value = input.ReadFloat();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -333,6 +374,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -341,7 +383,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `Int64Value` is JSON string.
   /// </summary>
-  public sealed partial class Int64Value : pb::IMessage<Int64Value>, pb::IBufferMessage {
+  public sealed partial class Int64Value : pb::IMessage<Int64Value>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Int64Value> _parser = new pb::MessageParser<Int64Value>(() => new Int64Value());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -457,9 +503,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Value = input.ReadInt64();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -475,6 +537,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -483,7 +546,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `UInt64Value` is JSON string.
   /// </summary>
-  public sealed partial class UInt64Value : pb::IMessage<UInt64Value>, pb::IBufferMessage {
+  public sealed partial class UInt64Value : pb::IMessage<UInt64Value>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<UInt64Value> _parser = new pb::MessageParser<UInt64Value>(() => new UInt64Value());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -599,9 +666,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Value = input.ReadUInt64();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -617,6 +700,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -625,7 +709,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `Int32Value` is JSON number.
   /// </summary>
-  public sealed partial class Int32Value : pb::IMessage<Int32Value>, pb::IBufferMessage {
+  public sealed partial class Int32Value : pb::IMessage<Int32Value>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<Int32Value> _parser = new pb::MessageParser<Int32Value>(() => new Int32Value());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -741,9 +829,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Value = input.ReadInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -759,6 +863,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -767,7 +872,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `UInt32Value` is JSON number.
   /// </summary>
-  public sealed partial class UInt32Value : pb::IMessage<UInt32Value>, pb::IBufferMessage {
+  public sealed partial class UInt32Value : pb::IMessage<UInt32Value>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<UInt32Value> _parser = new pb::MessageParser<UInt32Value>(() => new UInt32Value());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -883,9 +992,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Value = input.ReadUInt32();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -901,6 +1026,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -909,7 +1035,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `BoolValue` is JSON `true` and `false`.
   /// </summary>
-  public sealed partial class BoolValue : pb::IMessage<BoolValue>, pb::IBufferMessage {
+  public sealed partial class BoolValue : pb::IMessage<BoolValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<BoolValue> _parser = new pb::MessageParser<BoolValue>(() => new BoolValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1025,9 +1155,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 8: {
+            Value = input.ReadBool();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1043,6 +1189,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -1051,7 +1198,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `StringValue` is JSON string.
   /// </summary>
-  public sealed partial class StringValue : pb::IMessage<StringValue>, pb::IBufferMessage {
+  public sealed partial class StringValue : pb::IMessage<StringValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<StringValue> _parser = new pb::MessageParser<StringValue>(() => new StringValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1167,9 +1318,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Value = input.ReadString();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1185,6 +1352,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 
@@ -1193,7 +1361,11 @@ namespace Google.Protobuf.WellKnownTypes {
   ///
   /// The JSON representation for `BytesValue` is JSON string.
   /// </summary>
-  public sealed partial class BytesValue : pb::IMessage<BytesValue>, pb::IBufferMessage {
+  public sealed partial class BytesValue : pb::IMessage<BytesValue>
+  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
+      , pb::IBufferMessage
+  #endif
+  {
     private static readonly pb::MessageParser<BytesValue> _parser = new pb::MessageParser<BytesValue>(() => new BytesValue());
     private pb::UnknownFieldSet _unknownFields;
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
@@ -1309,9 +1481,25 @@ namespace Google.Protobuf.WellKnownTypes {
 
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     public void MergeFrom(pb::CodedInputStream input) {
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
       input.ReadRawMessage(this);
+    #else
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
+            break;
+          case 10: {
+            Value = input.ReadBytes();
+            break;
+          }
+        }
+      }
+    #endif
     }
 
+    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
     void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
       uint tag;
@@ -1327,6 +1515,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
       }
     }
+    #endif
 
   }
 

docs/third_party.md

@@ -18,6 +18,7 @@ These are projects we know about implementing Protocol Buffers for other program
 * C: https://github.com/squidfunk/protobluff
 * C: https://github.com/eerimoq/pbtools
 * C++: https://github.com/google/protobuf (Google-official implementation)
+* C++: https://EmbeddedProto.com
 * C/C++: http://spbc.sf.net/
 * C#: http://code.google.com/p/protobuf-csharp-port
 * C#: https://silentorbit.com/protobuf/

java/bom/pom.xml

@@ -4,7 +4,7 @@
 
   <groupId>com.google.protobuf</groupId>
   <artifactId>protobuf-bom</artifactId>
-  <version>3.12.2</version>
+  <version>3.12.3</version>
   <packaging>pom</packaging>
 
   <name>Protocol Buffers [BOM]</name>

java/core/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-parent</artifactId>
-    <version>3.12.2</version>
+    <version>3.12.3</version>
   </parent>
 
   <artifactId>protobuf-java</artifactId>

java/lite/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-parent</artifactId>
-    <version>3.12.2</version>
+    <version>3.12.3</version>
   </parent>
 
   <artifactId>protobuf-javalite</artifactId>

java/pom.xml

@@ -4,7 +4,7 @@
 
   <groupId>com.google.protobuf</groupId>
   <artifactId>protobuf-parent</artifactId>
-  <version>3.12.2</version>
+  <version>3.12.3</version>
   <packaging>pom</packaging>
 
   <name>Protocol Buffers [Parent]</name>

java/util/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>com.google.protobuf</groupId>
     <artifactId>protobuf-parent</artifactId>
-    <version>3.12.2</version>
+    <version>3.12.3</version>
   </parent>
 
   <artifactId>protobuf-java-util</artifactId>

java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java

@@ -30,6 +30,7 @@
 
 package com.google.protobuf.util;
 
+import com.google.common.base.Splitter;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.protobuf.Descriptors.Descriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
@@ -66,7 +67,7 @@ final class FieldMaskTree {
   private static final String FIELD_PATH_SEPARATOR_REGEX = "\\.";
 
   private static final class Node {
-    final SortedMap<String, Node> children = new TreeMap<String, Node>();
+    final SortedMap<String, Node> children = new TreeMap<>();
   }
 
   private final Node root = new Node();
@@ -97,6 +98,7 @@ final class FieldMaskTree {
    * to add is a sub-path of an existing leaf node, nothing will be changed in the tree.
    */
   @CanIgnoreReturnValue
+  @SuppressWarnings("StringSplitter")
   FieldMaskTree addFieldPath(String path) {
     String[] parts = path.split(FIELD_PATH_SEPARATOR_REGEX);
     if (parts.length == 0) {
@@ -134,6 +136,45 @@ final class FieldMaskTree {
     return this;
   }
 
+  /**
+   * Remove {@code path} from the tree.
+   *
+   * <p>When removing a field path from the tree, all sub-paths will be removed. That is, after
+   * removing "foo.bar" from the tree, "foo.bar.baz" will be removed. Likewise, if the field path to
+   * remove is a non-exist sub-path, nothing will be changed.
+   */
+  @CanIgnoreReturnValue
+  FieldMaskTree removeFieldPath(String path) {
+    List<String> parts = Splitter.onPattern(FIELD_PATH_SEPARATOR_REGEX).splitToList(path);
+    if (parts.isEmpty()) {
+      return this;
+    }
+    Node node = root;
+    for (int i = 0; i < parts.size(); i++) {
+      String key = parts.get(i);
+      if (!node.children.containsKey(key)) {
+        // Path does not exist.
+        return this;
+      }
+      if (i == parts.size() - 1) {
+        // Remove path.
+        node.children.remove(key);
+        return this;
+      }
+      node = node.children.get(key);
+    }
+    return this;
+  }
+
+  /** Removes all field paths in {@code mask} from this tree. */
+  @CanIgnoreReturnValue
+  FieldMaskTree removeFromFieldMask(FieldMask mask) {
+    for (String path : mask.getPathsList()) {
+      removeFieldPath(path);
+    }
+    return this;
+  }
+
   /**
    * Converts this tree to a FieldMask.
    */
@@ -141,7 +182,7 @@ final class FieldMaskTree {
     if (root.children.isEmpty()) {
       return FieldMask.getDefaultInstance();
     }
-    List<String> paths = new ArrayList<String>();
+    List<String> paths = new ArrayList<>();
     getFieldPaths(root, "", paths);
     return FieldMask.newBuilder().addAllPaths(paths).build();
   }
@@ -186,7 +227,7 @@ final class FieldMaskTree {
     }
     // We found a matching node for the path. All leaf children of this matching
     // node is in the intersection.
-    List<String> paths = new ArrayList<String>();
+    List<String> paths = new ArrayList<>();
     getFieldPaths(node, path, paths);
     for (String value : paths) {
       output.addFieldPath(value);

java/util/src/main/java/com/google/protobuf/util/FieldMaskUtil.java

@@ -276,6 +276,16 @@ public final class FieldMaskUtil {
     return maskTree.toFieldMask();
   }
 
+  /** Subtracts {@code secondMask} and {@code otherMasks} from {@code firstMask}. */
+  public static FieldMask subtract(
+      FieldMask firstMask, FieldMask secondMask, FieldMask... otherMasks) {
+    FieldMaskTree maskTree = new FieldMaskTree(firstMask).removeFromFieldMask(secondMask);
+    for (FieldMask mask : otherMasks) {
+      maskTree.removeFromFieldMask(mask);
+    }
+    return maskTree.toFieldMask();
+  }
+
   /**
    * Calculates the intersection of two FieldMasks.
    */

java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java

@@ -30,6 +30,8 @@
 
 package com.google.protobuf.util;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import com.google.protobuf.DynamicMessage;
 import com.google.protobuf.Message;
 import com.google.protobuf.UninitializedMessageException;
@@ -43,9 +45,9 @@ import junit.framework.TestCase;
 public class FieldMaskTreeTest extends TestCase {
   public void testAddFieldPath() throws Exception {
     FieldMaskTree tree = new FieldMaskTree();
-    assertEquals("", tree.toString());
+    assertThat(tree.toString()).isEmpty();
     tree.addFieldPath("");
-    assertEquals("", tree.toString());
+    assertThat(tree.toString()).isEmpty();
     // New branch.
     tree.addFieldPath("foo");
     assertEquals("foo", tree.toString());
@@ -73,15 +75,45 @@ public class FieldMaskTreeTest extends TestCase {
     assertEquals("bar,foo", tree.toString());
   }
 
+  public void testRemoveFieldPath() throws Exception {
+    String initialTreeString = "bar.baz,bar.quz.bar,foo";
+    FieldMaskTree tree = new FieldMaskTree(FieldMaskUtil.fromString(initialTreeString));
+    // Empty path.
+    tree.removeFieldPath("");
+    assertEquals(initialTreeString, tree.toString());
+    // Non-exist sub-path of an existing leaf.
+    tree.removeFieldPath("foo.bar");
+    assertEquals(initialTreeString, tree.toString());
+    // Non-exist path.
+    tree.removeFieldPath("bar.foo");
+    assertEquals(initialTreeString, tree.toString());
+    // Match an existing leaf node.
+    tree.removeFieldPath("foo");
+    assertEquals("bar.baz,bar.quz.bar", tree.toString());
+    // Match sub-path of an existing leaf node.
+    tree.removeFieldPath("bar.quz.bar");
+    assertEquals("bar.baz,bar.quz", tree.toString());
+    // Match a non-leaf node.
+    tree.removeFieldPath("bar");
+    assertThat(tree.toString()).isEmpty();
+  }
+
+  public void testRemoveFromFieldMask() throws Exception {
+    FieldMaskTree tree = new FieldMaskTree(FieldMaskUtil.fromString("foo,bar.baz,bar.quz"));
+    assertEquals("bar.baz,bar.quz,foo", tree.toString());
+    tree.removeFromFieldMask(FieldMaskUtil.fromString("foo.bar,bar"));
+    assertEquals("foo", tree.toString());
+  }
+
   public void testIntersectFieldPath() throws Exception {
     FieldMaskTree tree = new FieldMaskTree(FieldMaskUtil.fromString("foo,bar.baz,bar.quz"));
     FieldMaskTree result = new FieldMaskTree();
     // Empty path.
     tree.intersectFieldPath("", result);
-    assertEquals("", result.toString());
+    assertThat(result.toString()).isEmpty();
     // Non-exist path.
     tree.intersectFieldPath("quz", result);
-    assertEquals("", result.toString());
+    assertThat(result.toString()).isEmpty();
     // Sub-path of an existing leaf.
     tree.intersectFieldPath("foo.bar", result);
     assertEquals("foo.bar", result.toString());

java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java

@@ -224,6 +224,24 @@ public class FieldMaskUtilTest extends TestCase {
     assertEquals("bar,foo", FieldMaskUtil.toString(result));
   }
 
+  public void testSubstract() throws Exception {
+    // Only test a simple case here and expect
+    // {@link FieldMaskTreeTest#testRemoveFieldPath} to cover all scenarios.
+    FieldMask mask1 = FieldMaskUtil.fromString("foo,bar.baz,bar.quz");
+    FieldMask mask2 = FieldMaskUtil.fromString("foo.bar,bar");
+    FieldMask result = FieldMaskUtil.subtract(mask1, mask2);
+    assertEquals("foo", FieldMaskUtil.toString(result));
+  }
+
+  public void testSubstract_usingVarArgs() throws Exception {
+    FieldMask mask1 = FieldMaskUtil.fromString("foo,bar.baz,bar.quz.bar");
+    FieldMask mask2 = FieldMaskUtil.fromString("foo.bar,bar.baz.quz");
+    FieldMask mask3 = FieldMaskUtil.fromString("bar.quz");
+    FieldMask mask4 = FieldMaskUtil.fromString("foo,bar.baz");
+    FieldMask result = FieldMaskUtil.subtract(mask1, mask2, mask3, mask4);
+    assertEquals("bar", FieldMaskUtil.toString(result));
+  }
+
   public void testIntersection() throws Exception {
     // Only test a simple case here and expect
     // {@link FieldMaskTreeTest#testIntersectFieldPath} to cover all scenarios.

kokoro/macos/objectivec_cocoapods_integration/build.sh

@@ -6,6 +6,7 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_COCOAPODS=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh objectivec_cocoapods_integration

kokoro/macos/prepare_build_macos_rc

@@ -2,6 +2,8 @@
 #
 # This script sets up a Kokoro MacOS worker for running Protobuf tests
 
+set -eux
+
 ##
 # Select Xcode version
 
@@ -18,24 +20,61 @@ export CC=gcc
 export CXX=g++
 
 ##
-# Install Brew and core softwares
+# Brew: update, then upgrade the installed tools to current version and install
+# some needed ones not in the Kokoro base image. This ensure current versions
+# of CMake, autotools, etc.
+
+# But first...
+#
+# The transitive deps of the installed tools need protobuf, but Kokoro manually
+# installed it outside of brew so it needs to be removed so brew can install the
+# tools (and a newer version of protobuf). g/kokoro-users/7FRvQMUdN40 about why
+# it is a manual install vs. a brew install in the first place.
+sudo rm -rf \
+    /usr/local/include/google/protobuf \
+    /usr/local/bin/protoc
+# Likewise, updating python can have issues because of some existing binaries.
+sudo rm -rf \
+    /usr/local/bin/2to3* \
+    /usr/local/bin/idle3* \
+    /usr/local/bin/pydoc3* \
+    /usr/local/bin/python3* \
+    /usr/local/bin/pyvenv*
+
+brew update
+brew upgrade
+
+##
+# Install Ruby
 
-ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
-source $HOME/.rvm/scripts/rvm
-brew uninstall node icu4c cmake wget
-brew prune
-brew install gflags gpg gpg2 node openssl pcre ruby cmake wget
-sudo chown -R $(whoami) /usr/local
-brew postinstall node
+if [[ "${KOKORO_INSTALL_RUBY:-}" == "yes" ]] ; then
+  brew install ruby
+fi
+
+##
+# Install Cocoapods
+
+if [[ "${KOKORO_INSTALL_COCOAPODS:-}" == "yes" ]] ; then
+  # The existing cocoapods was installed via gem, but that doesn't work well
+  # with the overlap in deps with things managed by brew (errors around ruby
+  # versions, etc.); so remove it and install in via brew instead.
+  gem uninstall -a "$(gem list | grep cocoapods | cut -d ' ' -f 1)"
+  brew install cocoapods
+fi
 
 ##
 # Install Tox
 
-sudo pip install tox==2.4.1
+if [[ "${KOKORO_INSTALL_TOX:-}" == "yes" ]] ; then
+  sudo pip install tox==2.4.1
+fi
 
 ##
 # Install RVM
 
-gpg2 --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
-command curl -sSL https://rvm.io/mpapis.asc | gpg2 --import -
-curl -sSL https://get.rvm.io | bash -s stable --ruby
+if [[ "${KOKORO_INSTALL_RVM:-}" == "yes" ]] ; then
+  curl -sSL https://rvm.io/mpapis.asc | gpg --import -
+  curl -sSL https://rvm.io/pkuczynski.asc | gpg --import -
+
+  curl -sSL https://get.rvm.io | bash -s stable --ruby
+fi

kokoro/macos/python/build.sh

@@ -6,6 +6,7 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_TOX=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh python

kokoro/macos/python_cpp/build.sh

@@ -6,6 +6,7 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_TOX=yes
 source kokoro/macos/prepare_build_macos_rc
 g++ --version
 

kokoro/macos/ruby23/build.sh

@@ -6,6 +6,8 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_RUBY=yes
+KOKORO_INSTALL_RVM=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh ruby23

kokoro/macos/ruby24/build.sh

@@ -6,6 +6,8 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_RUBY=yes
+KOKORO_INSTALL_RVM=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh ruby24

kokoro/macos/ruby25/build.sh

@@ -6,6 +6,8 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_RUBY=yes
+KOKORO_INSTALL_RVM=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh ruby25

kokoro/macos/ruby26/build.sh

@@ -6,6 +6,8 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_RUBY=yes
+KOKORO_INSTALL_RVM=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh ruby26

kokoro/macos/ruby27/build.sh

@@ -6,6 +6,8 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_RUBY=yes
+KOKORO_INSTALL_RVM=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh ruby27

objectivec/GPBDescriptor_PackagePrivate.h

@@ -131,14 +131,29 @@ typedef NS_OPTIONS(uint8_t, GPBExtensionOptions) {
 typedef struct GPBExtensionDescription {
   GPBGenericValue defaultValue;
   const char *singletonName;
+  // Before 3.12, `extendedClass` was just a `const char *`. Thanks to nested
+  // initialization (https://en.cppreference.com/w/c/language/struct_initialization#Nested_initialization)
+  // old generated code with `.extendedClass = GPBStringifySymbol(Something)`
+  // still works; and the current generator can use `extendedClass.clazz`, to
+  // pass a Class reference.
   union {
     const char *name;
     Class clazz;
   } extendedClass;
+  // Before 3.12, this was `const char *messageOrGroupClassName`. In the
+  // initial 3.12 release, we moved the `union messageOrGroupClass`, and failed
+  // to realize that would break existing source code for extensions. So to
+  // keep existing source code working, we added an unnamed union (C11) to
+  // provide both the old field name and the new union. This keeps both older
+  // and newer code working.
+  // Background: https://github.com/protocolbuffers/protobuf/issues/7555
   union {
-    const char *name;
-    Class clazz;
-  } messageOrGroupClass;
+    const char *messageOrGroupClassName;
+    union {
+     const char *name;
+     Class clazz;
+   } messageOrGroupClass;
+  };
   GPBEnumDescriptorFunc enumDescriptorFunc;
   int32_t fieldNumber;
   GPBDataType dataType;

objectivec/README.md

@@ -172,6 +172,12 @@ supported keys are:
     lot of proto files included in it; and having multiple lines makes things
     easier to read.
 
+  * `runtime_import_prefix`: The `value` used for this key to be used as a
+    prefix on `#import`s of runtime provided headers in the generated files.
+    When integrating ObjC protos into a build system, this can be used to avoid
+    having to add the runtime directory to the header search path since the
+    generate `#import` will be more complete.
+
 Contributing
 ------------
 

php/composer.json

@@ -23,7 +23,7 @@
     }
   },
   "scripts": {
-    "test": "(cd tests && rm -rf generated && mkdir -p generated && ../../src/protoc --php_out=generated -I../../src -I. proto/empty/echo.proto proto/test.proto proto/test_include.proto proto/test_no_namespace.proto proto/test_prefix.proto proto/test_php_namespace.proto proto/test_empty_php_namespace.proto proto/test_reserved_enum_lower.proto proto/test_reserved_enum_upper.proto proto/test_reserved_enum_value_lower.proto proto/test_reserved_enum_value_upper.proto proto/test_reserved_message_lower.proto proto/test_reserved_message_upper.proto proto/test_service.proto proto/test_service_namespace.proto proto/test_wrapper_type_setters.proto proto/test_descriptors.proto) && (cd ../src && ./protoc --php_out=../php/tests/generated -I../php/tests -I. ../php/tests/proto/test_import_descriptor_proto.proto) && vendor/bin/phpunit",
-    "aggregate_metadata_test": "(cd tests && rm -rf generated && mkdir -p generated && ../../src/protoc --php_out=aggregate_metadata=foo#bar:generated -I../../src -I. proto/test.proto proto/test_include.proto && ../../src/protoc --php_out=generated -I../../src -I. proto/empty/echo.proto proto/test_no_namespace.proto proto/test_empty_php_namespace.proto proto/test_prefix.proto proto/test_php_namespace.proto proto/test_reserved_enum_lower.proto proto/test_reserved_enum_upper.proto proto/test_reserved_enum_value_lower.proto proto/test_reserved_enum_value_upper.proto proto/test_reserved_message_lower.proto proto/test_reserved_message_upper.proto proto/test_service.proto proto/test_service_namespace.proto proto/test_wrapper_type_setters.proto proto/test_descriptors.proto) && (cd ../src && ./protoc --php_out=aggregate_metadata=foo:../php/tests/generated -I../php/tests -I. ../php/tests/proto/test_import_descriptor_proto.proto) && vendor/bin/phpunit"
+    "test": "tests/generate_protos.sh && vendor/bin/phpunit",
+    "aggregate_metadata_test": "tests/generate_protos.sh --aggregate_metadata && vendor/bin/phpunit"
   }
 }

php/ext/google/protobuf/message.c

@@ -1726,7 +1726,7 @@ PHP_PROTO_INIT_SUBMSGCLASS_START("Google\\Protobuf\\Timestamp",
                              0 ,ZEND_ACC_PRIVATE TSRMLS_CC);
 PHP_PROTO_INIT_SUBMSGCLASS_END
 
-PHP_METHOD(Timestamp, __construct) {
+static PHP_METHOD(Timestamp, __construct) {
   init_file_timestamp(TSRMLS_C);
   INIT_MESSAGE_WITH_ARRAY;
 }

php/ext/google/protobuf/package.xml

@@ -10,11 +10,11 @@
   <email>protobuf-opensource@google.com</email>
   <active>yes</active>
  </lead>
- <date>2020-05-26</date>
- <time>13:57:10</time>
+ <date>2020-06-01</date>
+ <time>01:14:10</time>
  <version>
-  <release>3.12.2</release>
-  <api>3.12.2</api>
+  <release>3.12.3</release>
+  <api>3.12.3</api>
  </version>
  <stability>
   <release>stable</release>
@@ -599,5 +599,19 @@ G  A release.
    <license uri="https://opensource.org/licenses/BSD-3-Clause">3-Clause BSD License</license>
    <notes>GA release.</notes>
   </release>
+  <release>
+   <version>
+    <release>3.12.3</release>
+    <api>3.12.3</api>
+   </version>
+   <stability>
+    <release>stable</release>
+    <api>stable</api>
+   </stability>
+   <date>2020-06-01</date>
+   <time>01:09:39</time>
+   <license uri="https://opensource.org/licenses/BSD-3-Clause">3-Clause BSD License</license>
+   <notes>GA release.</notes>
+  </release>
  </changelog>
 </package>

php/ext/google/protobuf/protobuf.h

@@ -37,7 +37,7 @@
 #include "upb.h"
 
 #define PHP_PROTOBUF_EXTNAME "protobuf"
-#define PHP_PROTOBUF_VERSION "3.12.2"
+#define PHP_PROTOBUF_VERSION "3.12.3"
 
 #define MAX_LENGTH_OF_INT64 20
 #define SIZEOF_INT64 8
@@ -1292,7 +1292,7 @@ PHP_METHOD(Duration, setSeconds);
 PHP_METHOD(Duration, getNanos);
 PHP_METHOD(Duration, setNanos);
 
-PHP_METHOD(Timestamp, __construct);
+static PHP_METHOD(Timestamp, __construct);
 PHP_METHOD(Timestamp, fromDateTime);
 PHP_METHOD(Timestamp, toDateTime);
 PHP_METHOD(Timestamp, getSeconds);

php/tests/compile_extension.sh

@@ -1,8 +1,10 @@
 #!/bin/bash
 
+set -ex
+
 cd $(dirname $0)
 
-if [ "$1" = "--release"]; then
+if [ "$1" = "--release" ]; then
   CFLAGS="-Wall"
 else
   # To get debugging symbols in PHP itself, build PHP with:
@@ -12,6 +14,5 @@ fi
 
 pushd  ../ext/google/protobuf
 make clean || true
-set -e
 phpize && ./configure --with-php-config=$(which php-config) CFLAGS="$CFLAGS" && make
 popd

php/tests/generate_protos.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -ex
+
+cd `dirname $0`
+
+rm -rf generated
+mkdir -p generated
+
+find proto -type f -name "*.proto"| xargs ../../src/protoc --php_out=generated -I../../src -I.
+
+if [ "$1" = "--aggregate_metadata" ]; then
+  # Overwrite some of the files to use aggregation.
+  AGGREGATED_FILES="proto/test.proto proto/test_include.proto proto/test_import_descriptor_proto.proto"
+  ../../src/protoc --php_out=aggregate_metadata=foo#bar:generated -I../../src -I. $AGGREGATED_FILES
+fi

php/tests/generated_class_test.php

@@ -1527,6 +1527,21 @@ class GeneratedClassTest extends TestBase
     public function testNoExceptionWithVarDump()
     {
         $m = new Sub(['a' => 1]);
-        var_dump($m);
+        /*
+         * This line currently segfaults on macOS with:
+         *
+         *    frame #0: 0x00000001029936cc xdebug.so`xdebug_zend_hash_is_recursive + 4
+         *    frame #1: 0x00000001029a6736 xdebug.so`xdebug_var_export_text_ansi + 1006
+         *    frame #2: 0x00000001029a715d xdebug.so`xdebug_get_zval_value_text_ansi + 273
+         *    frame #3: 0x000000010298a441 xdebug.so`zif_xdebug_var_dump + 297
+         *    frame #4: 0x000000010298d558 xdebug.so`xdebug_execute_internal + 640
+         *    frame #5: 0x000000010046d47f php`ZEND_DO_FCALL_SPEC_RETVAL_UNUSED_HANDLER + 364
+         *    frame #6: 0x000000010043cabc php`execute_ex + 44
+         *    frame #7: 0x000000010298d151 xdebug.so`xdebug_execute_ex + 1662
+         *    frame #8: 0x000000010046d865 php`ZEND_DO_FCALL_SPEC_RETVAL_USED_HANDLER + 426
+         *
+         * The value we are passing to var_dump() appears to be corrupt somehow.
+         */
+        /* var_dump($m); */
     }
 }

php/tests/test.sh

@@ -1,9 +1,23 @@
 #!/bin/bash
 
+set -ex
+
 cd $(dirname $0)
 
+./generate_protos.sh
 ./compile_extension.sh
 
+PHP_VERSION=$(php -r "echo PHP_VERSION;")
+
+# Each version of PHPUnit supports a fairly narrow range of PHP versions.
+case "$PHP_VERSION" in
+  5.6.*) PHPUNIT=phpunit-5.6.8.phar;;
+  7.0.*) PHPUNIT=phpunit-5.6.0.phar;;  # Oddly older than for 5.6. Not sure the reason.
+  7.3.*) PHPUNIT=phpunit-8.phar;;
+esac
+
+[ -f $PHPUNIT ] || wget https://phar.phpunit.de/$PHPUNIT
+
 tests=( array_test.php encode_decode_test.php generated_class_test.php map_field_test.php well_known_test.php descriptors_test.php wrapper_type_setters_test.php)
 
 for t in "${tests[@]}"
@@ -11,7 +25,7 @@ do
   echo "****************************"
   echo "* $t"
   echo "****************************"
-  php -dextension=../ext/google/protobuf/modules/protobuf.so `which phpunit` --bootstrap autoload.php $t
+  php -dextension=../ext/google/protobuf/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
   echo ""
 done
 
@@ -20,7 +34,7 @@ do
   echo "****************************"
   echo "* $t persistent"
   echo "****************************"
-  php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf/modules/protobuf.so `which phpunit` --bootstrap autoload.php $t
+  php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
   echo ""
 done
 
@@ -40,6 +54,6 @@ valgrind --leak-check=yes php -d protobuf.keep_descriptor_pool_after_request=1 -
 #   echo "****************************"
 #   echo "* $t (memory leak)"
 #   echo "****************************"
-#   valgrind --leak-check=yes php -dextension=../ext/google/protobuf/modules/protobuf.so `which phpunit` --bootstrap autoload.php $t
+#   valgrind --leak-check=yes php -dextension=../ext/google/protobuf/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
 #   echo ""
 # done

protoc-artifacts/pom.xml

@@ -8,7 +8,7 @@
   </parent>
   <groupId>com.google.protobuf</groupId>
   <artifactId>protoc</artifactId>
-  <version>3.12.2</version>
+  <version>3.12.3</version>
   <packaging>pom</packaging>
   <name>Protobuf Compiler</name>
   <description>

python/google/protobuf/internal/decoder.py

@@ -209,7 +209,8 @@ def _SimpleDecoder(wire_type, decode_value):
         _DecodeVarint()
   """
 
-  def SpecificDecoder(field_number, is_repeated, is_packed, key, new_default):
+  def SpecificDecoder(field_number, is_repeated, is_packed, key, new_default,
+                      clear_if_default=False):
     if is_packed:
       local_DecodeVarint = _DecodeVarint
       def DecodePackedField(buffer, pos, end, message, field_dict):
@@ -249,10 +250,13 @@ def _SimpleDecoder(wire_type, decode_value):
       return DecodeRepeatedField
     else:
       def DecodeField(buffer, pos, end, message, field_dict):
-        (field_dict[key], pos) = decode_value(buffer, pos)
+        (new_value, pos) = decode_value(buffer, pos)
         if pos > end:
-          del field_dict[key]  # Discard corrupt value.
           raise _DecodeError('Truncated message.')
+        if clear_if_default and not new_value:
+          field_dict.pop(key, None)
+        else:
+          field_dict[key] = new_value
         return pos
       return DecodeField
 
@@ -383,7 +387,9 @@ def _DoubleDecoder():
   return _SimpleDecoder(wire_format.WIRETYPE_FIXED64, InnerDecode)
 
 
-def EnumDecoder(field_number, is_repeated, is_packed, key, new_default):
+def EnumDecoder(field_number, is_repeated, is_packed, key, new_default,
+                clear_if_default=False):
+  """Returns a decoder for enum field."""
   enum_type = key.enum_type
   if is_packed:
     local_DecodeVarint = _DecodeVarint
@@ -498,6 +504,9 @@ def EnumDecoder(field_number, is_repeated, is_packed, key, new_default):
       (enum_value, pos) = _DecodeSignedVarint32(buffer, pos)
       if pos > end:
         raise _DecodeError('Truncated message.')
+      if clear_if_default and not enum_value:
+        field_dict.pop(key, None)
+        return pos
       # pylint: disable=protected-access
       if enum_value in enum_type.values_by_number:
         field_dict[key] = enum_value
@@ -550,7 +559,7 @@ BoolDecoder = _ModifiedDecoder(
 
 
 def StringDecoder(field_number, is_repeated, is_packed, key, new_default,
-                  is_strict_utf8=False):
+                  is_strict_utf8=False, clear_if_default=False):
   """Returns a decoder for a string field."""
 
   local_DecodeVarint = _DecodeVarint
@@ -604,12 +613,16 @@ def StringDecoder(field_number, is_repeated, is_packed, key, new_default,
       new_pos = pos + size
       if new_pos > end:
         raise _DecodeError('Truncated string.')
-      field_dict[key] = _ConvertToUnicode(buffer[pos:new_pos])
+      if clear_if_default and not size:
+        field_dict.pop(key, None)
+      else:
+        field_dict[key] = _ConvertToUnicode(buffer[pos:new_pos])
       return new_pos
     return DecodeField
 
 
-def BytesDecoder(field_number, is_repeated, is_packed, key, new_default):
+def BytesDecoder(field_number, is_repeated, is_packed, key, new_default,
+                 clear_if_default=False):
   """Returns a decoder for a bytes field."""
 
   local_DecodeVarint = _DecodeVarint
@@ -641,7 +654,10 @@ def BytesDecoder(field_number, is_repeated, is_packed, key, new_default):
       new_pos = pos + size
       if new_pos > end:
         raise _DecodeError('Truncated string.')
-      field_dict[key] = buffer[pos:new_pos].tobytes()
+      if clear_if_default and not size:
+        field_dict.pop(key, None)
+      else:
+        field_dict[key] = buffer[pos:new_pos].tobytes()
       return new_pos
     return DecodeField
 

python/google/protobuf/internal/encoder.py

@@ -372,14 +372,15 @@ def MapSizer(field_descriptor, is_message_map):
 def _VarintEncoder():
   """Return an encoder for a basic varint value (does not include tag)."""
 
+  local_int2byte = six.int2byte
   def EncodeVarint(write, value, unused_deterministic=None):
     bits = value & 0x7f
     value >>= 7
     while value:
-      write(six.int2byte(0x80|bits))
+      write(local_int2byte(0x80|bits))
       bits = value & 0x7f
       value >>= 7
-    return write(six.int2byte(bits))
+    return write(local_int2byte(bits))
 
   return EncodeVarint
 
@@ -388,16 +389,17 @@ def _SignedVarintEncoder():
   """Return an encoder for a basic signed varint value (does not include
   tag)."""
 
+  local_int2byte = six.int2byte
   def EncodeSignedVarint(write, value, unused_deterministic=None):
     if value < 0:
       value += (1 << 64)
     bits = value & 0x7f
     value >>= 7
     while value:
-      write(six.int2byte(0x80|bits))
+      write(local_int2byte(0x80|bits))
       bits = value & 0x7f
       value >>= 7
-    return write(six.int2byte(bits))
+    return write(local_int2byte(bits))
 
   return EncodeSignedVarint
 

python/google/protobuf/internal/json_format_test.py

@@ -830,10 +830,14 @@ class JsonFormatTest(JsonFormatBase):
 
   def testParseDoubleToFloat(self):
     message = json_format_proto3_pb2.TestMessage()
-    text = ('{"repeatedFloatValue": [3.4028235e+39, 1.4028235e-39]\n}')
+    text = ('{"repeatedDoubleValue": [3.4028235e+39, 1.4028235e-39]\n}')
     json_format.Parse(text, message)
-    self.assertEqual(message.repeated_float_value[0], float('inf'))
-    self.assertAlmostEqual(message.repeated_float_value[1], 1.4028235e-39)
+    self.assertEqual(message.repeated_double_value[0], 3.4028235e+39)
+    self.assertEqual(message.repeated_double_value[1], 1.4028235e-39)
+    text = ('{"repeatedFloatValue": [3.4028235e+39, 1.4028235e-39]\n}')
+    self.CheckError(text,
+                    'Failed to parse repeatedFloatValue field: '
+                    'Float value too large.')
 
   def testFloatPrecision(self):
     message = json_format_proto3_pb2.TestMessage()
@@ -898,6 +902,23 @@ class JsonFormatTest(JsonFormatBase):
         'for enum type protobuf_unittest.TestAllTypes.NestedEnum.',
         json_format.Parse, '{"optionalNestedEnum": 12345}', message)
 
+  def testBytes(self):
+    message = json_format_proto3_pb2.TestMessage()
+    # Test url base64
+    text = '{"bytesValue": "-_"}'
+    json_format.Parse(text, message)
+    self.assertEqual(message.bytes_value, b'\xfb')
+    # Test padding
+    text = '{"bytesValue": "AQI="}'
+    json_format.Parse(text, message)
+    self.assertEqual(message.bytes_value, b'\x01\x02')
+    text = '{"bytesValue": "AQI"}'
+    json_format.Parse(text, message)
+    self.assertEqual(message.bytes_value, b'\x01\x02')
+    text = '{"bytesValue": "AQI*"}'
+    json_format.Parse(text, message)
+    self.assertEqual(message.bytes_value, b'\x01\x02')
+
   def testParseBadIdentifer(self):
     self.CheckError('{int32Value: 1}',
                     (r'Failed to load JSON: Expecting property name'
@@ -948,6 +969,9 @@ class JsonFormatTest(JsonFormatBase):
     self.CheckError('{"int32Value": "1 "}',
                     'Failed to parse int32Value field: '
                     'Couldn\'t parse integer: "1 ".')
+    self.CheckError('{"int32Value": false}',
+                    'Failed to parse int32Value field: Bool value False '
+                    'is not acceptable for integer field.')
     self.CheckError('{"int32Value": 12345678901234567890}',
                     'Failed to parse int32Value field: Value out of range: '
                     '12345678901234567890.')
@@ -959,12 +983,24 @@ class JsonFormatTest(JsonFormatBase):
     self.CheckError('{"floatValue": "nan"}',
                     'Failed to parse floatValue field: Couldn\'t '
                     'parse float "nan", use "NaN" instead.')
-
-  def testInvalidBytesValue(self):
-    self.CheckError('{"bytesValue": "AQI"}',
-                    'Failed to parse bytesValue field: Incorrect padding.')
-    self.CheckError('{"bytesValue": "AQI*"}',
-                    'Failed to parse bytesValue field: Incorrect padding.')
+    self.CheckError('{"floatValue": NaN}',
+                    'Failed to parse floatValue field: Couldn\'t '
+                    'parse NaN, use quoted "NaN" instead.')
+    self.CheckError('{"floatValue": Infinity}',
+                    'Failed to parse floatValue field: Couldn\'t parse Infinity'
+                    ' or value too large, use quoted "Infinity" instead.')
+    self.CheckError('{"floatValue": -Infinity}',
+                    'Failed to parse floatValue field: Couldn\'t parse '
+                    '-Infinity or value too small, '
+                    'use quoted "-Infinity" instead.')
+    self.CheckError('{"doubleValue": -1.89769e+308}',
+                    'Failed to parse doubleValue field: Couldn\'t parse '
+                    '-Infinity or value too small, '
+                    'use quoted "-Infinity" instead.')
+    self.CheckError('{"floatValue": 3.4028235e+39}',
+                    'Failed to parse floatValue field: Float value too large.')
+    self.CheckError('{"floatValue": -3.502823e+38}',
+                    'Failed to parse floatValue field: Float value too small.')
 
   def testInvalidRepeated(self):
     self.CheckError('{"repeatedInt32Value": 12345}',

python/google/protobuf/internal/message_test.py

@@ -1675,6 +1675,17 @@ class Proto3Test(unittest.TestCase):
     self.assertEqual(False, message.optional_bool)
     self.assertEqual(0, message.optional_nested_message.bb)
 
+  def testProto3ParserDropDefaultScalar(self):
+    message_proto2 = unittest_pb2.TestAllTypes()
+    message_proto2.optional_int32 = 0
+    message_proto2.optional_string = ''
+    message_proto2.optional_bytes = b''
+    self.assertEqual(len(message_proto2.ListFields()), 3)
+
+    message_proto3 = unittest_proto3_arena_pb2.TestAllTypes()
+    message_proto3.ParseFromString(message_proto2.SerializeToString())
+    self.assertEqual(len(message_proto3.ListFields()), 0)
+
   def testProto3Optional(self):
     msg = test_proto3_optional_pb2.TestProto3Optional()
     self.assertFalse(msg.HasField('optional_int32'))

python/google/protobuf/internal/python_message.py

@@ -295,6 +295,7 @@ def _AttachFieldHelpers(cls, field_descriptor):
   is_repeated = (field_descriptor.label == _FieldDescriptor.LABEL_REPEATED)
   is_packable = (is_repeated and
                  wire_format.IsTypePackable(field_descriptor.type))
+  is_proto3 = field_descriptor.containing_type.syntax == 'proto3'
   if not is_packable:
     is_packed = False
   elif field_descriptor.containing_type.syntax == 'proto2':
@@ -333,8 +334,12 @@ def _AttachFieldHelpers(cls, field_descriptor):
       decode_type = _FieldDescriptor.TYPE_INT32
 
     oneof_descriptor = None
+    clear_if_default = False
     if field_descriptor.containing_oneof is not None:
       oneof_descriptor = field_descriptor
+    elif (is_proto3 and not is_repeated and
+          field_descriptor.cpp_type != _FieldDescriptor.CPPTYPE_MESSAGE):
+      clear_if_default = True
 
     if is_map_entry:
       is_message_map = _IsMessageMapField(field_descriptor)
@@ -347,11 +352,17 @@ def _AttachFieldHelpers(cls, field_descriptor):
       field_decoder = decoder.StringDecoder(
           field_descriptor.number, is_repeated, is_packed,
           field_descriptor, field_descriptor._default_constructor,
-          is_strict_utf8_check)
-    else:
+          is_strict_utf8_check, clear_if_default)
+    elif field_descriptor.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE:
       field_decoder = type_checkers.TYPE_TO_DECODER[decode_type](
           field_descriptor.number, is_repeated, is_packed,
           field_descriptor, field_descriptor._default_constructor)
+    else:
+      field_decoder = type_checkers.TYPE_TO_DECODER[decode_type](
+          field_descriptor.number, is_repeated, is_packed,
+          # pylint: disable=protected-access
+          field_descriptor, field_descriptor._default_constructor,
+          clear_if_default)
 
     cls._decoders_by_tag[tag_bytes] = (field_decoder, oneof_descriptor)
 

python/google/protobuf/json_format.py

@@ -195,7 +195,6 @@ class _Printer(object):
     self.preserving_proto_field_name = preserving_proto_field_name
     self.use_integers_for_enums = use_integers_for_enums
     self.descriptor_pool = descriptor_pool
-    # TODO(jieluo): change the float precision default to 8 valid digits.
     if float_precision:
       self.float_format = '.{}g'.format(float_precision)
     else:
@@ -720,12 +719,18 @@ def _ConvertScalarFieldValue(value, field, require_str=False):
   if field.cpp_type in _INT_TYPES:
     return _ConvertInteger(value)
   elif field.cpp_type in _FLOAT_TYPES:
-    return _ConvertFloat(value)
+    return _ConvertFloat(value, field)
   elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_BOOL:
     return _ConvertBool(value, require_str)
   elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_STRING:
     if field.type == descriptor.FieldDescriptor.TYPE_BYTES:
-      return base64.b64decode(value)
+      if isinstance(value, six.text_type):
+        encoded = value.encode('utf-8')
+      else:
+        encoded = value
+      # Add extra padding '='
+      padded_value = encoded + b'=' * (4 - len(encoded) % 4)
+      return base64.urlsafe_b64decode(padded_value)
     else:
       # Checking for unpaired surrogates appears to be unreliable,
       # depending on the specific Python version, so we check manually.
@@ -769,11 +774,32 @@ def _ConvertInteger(value):
   if isinstance(value, six.text_type) and value.find(' ') != -1:
     raise ParseError('Couldn\'t parse integer: "{0}".'.format(value))
 
+  if isinstance(value, bool):
+    raise ParseError('Bool value {0} is not acceptable for '
+                     'integer field.'.format(value))
+
   return int(value)
 
 
-def _ConvertFloat(value):
+def _ConvertFloat(value, field):
   """Convert an floating point number."""
+  if isinstance(value, float):
+    if math.isnan(value):
+      raise ParseError('Couldn\'t parse NaN, use quoted "NaN" instead.')
+    if math.isinf(value):
+      if value > 0:
+        raise ParseError('Couldn\'t parse Infinity or value too large, '
+                         'use quoted "Infinity" instead.')
+      else:
+        raise ParseError('Couldn\'t parse -Infinity or value too small, '
+                         'use quoted "-Infinity" instead.')
+    if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_FLOAT:
+      # pylint: disable=protected-access
+      if value > type_checkers._FLOAT_MAX:
+        raise ParseError('Float value too large')
+      # pylint: disable=protected-access
+      if value < type_checkers._FLOAT_MIN:
+        raise ParseError('Float value too small')
   if value == 'nan':
     raise ParseError('Couldn\'t parse float "nan", use "NaN" instead.')
   try:

python/google/protobuf/pyext/descriptor.cc

@@ -1690,7 +1690,7 @@ static PyObject* FindMethodByName(PyBaseDescriptor *self, PyObject* arg) {
   }
 
   const MethodDescriptor* method_descriptor =
-      _GetDescriptor(self)->FindMethodByName(std::string(name, name_size));
+      _GetDescriptor(self)->FindMethodByName(StringParam(name, name_size));
   if (method_descriptor == NULL) {
     PyErr_Format(PyExc_KeyError, "Couldn't find method %.200s", name);
     return NULL;

python/google/protobuf/pyext/descriptor.h

@@ -41,6 +41,9 @@ namespace google {
 namespace protobuf {
 namespace python {
 
+// Should match the type of ConstStringParam.
+using StringParam = std::string;
+
 extern PyTypeObject PyMessageDescriptor_Type;
 extern PyTypeObject PyFieldDescriptor_Type;
 extern PyTypeObject PyEnumDescriptor_Type;

python/google/protobuf/pyext/descriptor_containers.cc

@@ -81,9 +81,9 @@ struct PyContainer;
 typedef int (*CountMethod)(PyContainer* self);
 typedef const void* (*GetByIndexMethod)(PyContainer* self, int index);
 typedef const void* (*GetByNameMethod)(PyContainer* self,
-                                       const std::string& name);
+                                       ConstStringParam name);
 typedef const void* (*GetByCamelcaseNameMethod)(PyContainer* self,
-                                                const std::string& name);
+                                                ConstStringParam name);
 typedef const void* (*GetByNumberMethod)(PyContainer* self, int index);
 typedef PyObject* (*NewObjectFromItemMethod)(const void* descriptor);
 typedef const std::string& (*GetItemNameMethod)(const void* descriptor);
@@ -183,7 +183,7 @@ static bool _GetItemByKey(PyContainer* self, PyObject* key, const void** item) {
           return false;
         }
         *item = self->container_def->get_by_name_fn(
-            self, std::string(name, name_size));
+            self, StringParam(name, name_size));
         return true;
       }
     case PyContainer::KIND_BYCAMELCASENAME:
@@ -200,7 +200,7 @@ static bool _GetItemByKey(PyContainer* self, PyObject* key, const void** item) {
           return false;
         }
         *item = self->container_def->get_by_camelcase_name_fn(
-            self, std::string(camelcase_name, name_size));
+            self, StringParam(camelcase_name, name_size));
         return true;
       }
     case PyContainer::KIND_BYNUMBER:
@@ -962,12 +962,12 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->field_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindFieldByName(name);
 }
 
 static const void* GetByCamelcaseName(PyContainer* self,
-                                      const std::string& name) {
+                                      ConstStringParam name) {
   return GetDescriptor(self)->FindFieldByCamelcaseName(name);
 }
 
@@ -1040,7 +1040,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->nested_type_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindNestedTypeByName(name);
 }
 
@@ -1092,7 +1092,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->enum_type_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindEnumTypeByName(name);
 }
 
@@ -1155,7 +1155,7 @@ static int Count(PyContainer* self) {
   return count;
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindEnumValueByName(name);
 }
 
@@ -1215,7 +1215,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->extension_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindExtensionByName(name);
 }
 
@@ -1267,7 +1267,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->oneof_decl_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindOneofByName(name);
 }
 
@@ -1333,7 +1333,7 @@ static const void* GetByIndex(PyContainer* self, int index) {
   return GetDescriptor(self)->value(index);
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindValueByName(name);
 }
 
@@ -1454,7 +1454,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->method_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindMethodByName(name);
 }
 
@@ -1516,7 +1516,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->message_type_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindMessageTypeByName(name);
 }
 
@@ -1564,7 +1564,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->enum_type_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindEnumTypeByName(name);
 }
 
@@ -1612,7 +1612,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->extension_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindExtensionByName(name);
 }
 
@@ -1660,7 +1660,7 @@ static int Count(PyContainer* self) {
   return GetDescriptor(self)->service_count();
 }
 
-static const void* GetByName(PyContainer* self, const std::string& name) {
+static const void* GetByName(PyContainer* self, ConstStringParam name) {
   return GetDescriptor(self)->FindServiceByName(name);
 }
 

python/google/protobuf/pyext/descriptor_pool.cc

@@ -240,7 +240,7 @@ static PyObject* FindMessageByName(PyObject* self, PyObject* arg) {
 
   const Descriptor* message_descriptor =
       reinterpret_cast<PyDescriptorPool*>(self)->pool->FindMessageTypeByName(
-          std::string(name, name_size));
+          StringParam(name, name_size));
 
   if (message_descriptor == NULL) {
     return SetErrorFromCollector(
@@ -264,7 +264,7 @@ static PyObject* FindFileByName(PyObject* self, PyObject* arg) {
 
   PyDescriptorPool* py_pool = reinterpret_cast<PyDescriptorPool*>(self);
   const FileDescriptor* file_descriptor =
-      py_pool->pool->FindFileByName(std::string(name, name_size));
+      py_pool->pool->FindFileByName(StringParam(name, name_size));
 
   if (file_descriptor == NULL) {
     return SetErrorFromCollector(py_pool->error_collector, name, "file");
@@ -280,7 +280,7 @@ PyObject* FindFieldByName(PyDescriptorPool* self, PyObject* arg) {
   }
 
   const FieldDescriptor* field_descriptor =
-      self->pool->FindFieldByName(std::string(name, name_size));
+      self->pool->FindFieldByName(StringParam(name, name_size));
   if (field_descriptor == NULL) {
     return SetErrorFromCollector(self->error_collector, name, "field");
   }
@@ -301,7 +301,7 @@ PyObject* FindExtensionByName(PyDescriptorPool* self, PyObject* arg) {
   }
 
   const FieldDescriptor* field_descriptor =
-      self->pool->FindExtensionByName(std::string(name, name_size));
+      self->pool->FindExtensionByName(StringParam(name, name_size));
   if (field_descriptor == NULL) {
     return SetErrorFromCollector(self->error_collector, name,
                                  "extension field");
@@ -323,7 +323,7 @@ PyObject* FindEnumTypeByName(PyDescriptorPool* self, PyObject* arg) {
   }
 
   const EnumDescriptor* enum_descriptor =
-      self->pool->FindEnumTypeByName(std::string(name, name_size));
+      self->pool->FindEnumTypeByName(StringParam(name, name_size));
   if (enum_descriptor == NULL) {
     return SetErrorFromCollector(self->error_collector, name, "enum");
   }
@@ -344,7 +344,7 @@ PyObject* FindOneofByName(PyDescriptorPool* self, PyObject* arg) {
   }
 
   const OneofDescriptor* oneof_descriptor =
-      self->pool->FindOneofByName(std::string(name, name_size));
+      self->pool->FindOneofByName(StringParam(name, name_size));
   if (oneof_descriptor == NULL) {
     return SetErrorFromCollector(self->error_collector, name, "oneof");
   }
@@ -366,7 +366,7 @@ static PyObject* FindServiceByName(PyObject* self, PyObject* arg) {
 
   const ServiceDescriptor* service_descriptor =
       reinterpret_cast<PyDescriptorPool*>(self)->pool->FindServiceByName(
-          std::string(name, name_size));
+          StringParam(name, name_size));
   if (service_descriptor == NULL) {
     return SetErrorFromCollector(
         reinterpret_cast<PyDescriptorPool*>(self)->error_collector, name,
@@ -386,7 +386,7 @@ static PyObject* FindMethodByName(PyObject* self, PyObject* arg) {
 
   const MethodDescriptor* method_descriptor =
       reinterpret_cast<PyDescriptorPool*>(self)->pool->FindMethodByName(
-          std::string(name, name_size));
+          StringParam(name, name_size));
   if (method_descriptor == NULL) {
     return SetErrorFromCollector(
         reinterpret_cast<PyDescriptorPool*>(self)->error_collector, name,
@@ -406,7 +406,7 @@ static PyObject* FindFileContainingSymbol(PyObject* self, PyObject* arg) {
 
   const FileDescriptor* file_descriptor =
       reinterpret_cast<PyDescriptorPool*>(self)->pool->FindFileContainingSymbol(
-          std::string(name, name_size));
+          StringParam(name, name_size));
   if (file_descriptor == NULL) {
     return SetErrorFromCollector(
         reinterpret_cast<PyDescriptorPool*>(self)->error_collector, name,

python/google/protobuf/pyext/extension_dict.cc

@@ -240,11 +240,11 @@ PyObject* _FindExtensionByName(ExtensionDict* self, PyObject* arg) {
 
   PyDescriptorPool* pool = cmessage::GetFactoryForMessage(self->parent)->pool;
   const FieldDescriptor* message_extension =
-      pool->pool->FindExtensionByName(std::string(name, name_size));
+      pool->pool->FindExtensionByName(StringParam(name, name_size));
   if (message_extension == NULL) {
     // Is is the name of a message set extension?
     const Descriptor* message_descriptor =
-        pool->pool->FindMessageTypeByName(std::string(name, name_size));
+        pool->pool->FindMessageTypeByName(StringParam(name, name_size));
     if (message_descriptor && message_descriptor->extension_count() > 0) {
       const FieldDescriptor* extension = message_descriptor->extension(0);
       if (extension->is_extension() &&

python/google/protobuf/pyext/message.cc

@@ -243,7 +243,7 @@ static PyObject* New(PyTypeObject* type,
     }
     message_descriptor =
         GetDefaultDescriptorPool()->pool->FindMessageTypeByName(
-            std::string(full_name, name_size));
+            StringParam(full_name, name_size));
     if (message_descriptor == nullptr) {
       PyErr_Format(PyExc_KeyError,
                    "Can not find message descriptor %s "
@@ -984,7 +984,7 @@ static PyObject* GetIntegerEnumValue(const FieldDescriptor& descriptor,
       return NULL;
     }
     const EnumValueDescriptor* enum_value_descriptor =
-        enum_descriptor->FindValueByName(std::string(enum_label, size));
+        enum_descriptor->FindValueByName(StringParam(enum_label, size));
     if (enum_value_descriptor == NULL) {
       PyErr_Format(PyExc_ValueError, "unknown enum label \"%s\"", enum_label);
       return NULL;
@@ -1399,7 +1399,7 @@ int HasFieldByDescriptor(CMessage* self,
 }
 
 const FieldDescriptor* FindFieldWithOneofs(const Message* message,
-                                           const std::string& field_name,
+                                           ConstStringParam field_name,
                                            bool* in_oneof) {
   *in_oneof = false;
   const Descriptor* descriptor = message->GetDescriptor();
@@ -1455,7 +1455,7 @@ PyObject* HasField(CMessage* self, PyObject* arg) {
   Message* message = self->message;
   bool is_in_oneof;
   const FieldDescriptor* field_descriptor =
-      FindFieldWithOneofs(message, std::string(field_name, size), &is_in_oneof);
+      FindFieldWithOneofs(message, StringParam(field_name, size), &is_in_oneof);
   if (field_descriptor == NULL) {
     if (!is_in_oneof) {
       PyErr_Format(PyExc_ValueError, "Protocol message %s has no field %s.",
@@ -1632,7 +1632,7 @@ PyObject* ClearField(CMessage* self, PyObject* arg) {
   AssureWritable(self);
   bool is_in_oneof;
   const FieldDescriptor* field_descriptor = FindFieldWithOneofs(
-      self->message, std::string(field_name, field_size), &is_in_oneof);
+      self->message, StringParam(field_name, field_size), &is_in_oneof);
   if (field_descriptor == NULL) {
     if (is_in_oneof) {
       // We gave the name of a oneof, and none of its fields are set.
@@ -2033,13 +2033,12 @@ static PyObject* WhichOneof(CMessage* self, PyObject* arg) {
   char *name_data;
   if (PyString_AsStringAndSize(arg, &name_data, &name_size) < 0)
     return NULL;
-  std::string oneof_name = std::string(name_data, name_size);
   const OneofDescriptor* oneof_desc =
-      self->message->GetDescriptor()->FindOneofByName(oneof_name);
+      self->message->GetDescriptor()->FindOneofByName(
+          StringParam(name_data, name_size));
   if (oneof_desc == NULL) {
     PyErr_Format(PyExc_ValueError,
-                 "Protocol message has no oneof \"%s\" field.",
-                 oneof_name.c_str());
+                 "Protocol message has no oneof \"%s\" field.", name_data);
     return NULL;
   }
   const FieldDescriptor* field_in_oneof =

python/release.sh

@@ -80,14 +80,16 @@ python setup.py build
 python setup.py test
 
 # Deploy source package to testing PyPI
-python setup.py sdist upload -r https://test.pypi.org/legacy/
+python setup.py sdist
+twine upload --skip-existing -r testpypi -u protobuf-wheel-test dist/*
 
 # Test locally with different python versions.
 run_install_test ${TESTING_VERSION} python2.7 https://test.pypi.org/simple
 run_install_test ${TESTING_VERSION} python3 https://test.pypi.org/simple
 
 # Deploy egg/wheel packages to testing PyPI and test again.
-python setup.py bdist_egg bdist_wheel upload -r https://test.pypi.org/legacy/
+python setup.py clean build bdist_wheel
+twine upload --skip-existing -r testpypi -u protobuf-wheel-test dist/*
 
 run_install_test ${TESTING_VERSION} python2.7 https://test.pypi.org/simple
 run_install_test ${TESTING_VERSION} python3 https://test.pypi.org/simple
@@ -103,13 +105,15 @@ if [ $TESTING_ONLY -eq 0 ]; then
   echo "Publishing to PyPI..."
   # Be sure to run build before sdist, because otherwise sdist will not include
   # well-known types.
-  python setup.py clean build sdist upload
+  python setup.py clean build sdist
+  twine upload --skip-existing -u protobuf-packages dist/*
   # Be sure to run clean before bdist_xxx, because otherwise bdist_xxx will
   # include files you may not want in the package. E.g., if you have built
   # and tested with --cpp_implemenation, bdist_xxx will include the _message.so
   # file even when you no longer pass the --cpp_implemenation flag. See:
   #   https://github.com/protocolbuffers/protobuf/issues/3042
-  python setup.py clean build bdist_egg bdist_wheel upload
+  python setup.py clean build bdist_wheel
+  twine upload --skip-existing -u protobuf-packages dist/*
 else
   # Set the version number back (i.e., remove dev suffix).
   sed -i -r "s/__version__ = '.*'/__version__ = '${VERSION}'/" google/protobuf/__init__.py

ruby/google-protobuf.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name        = "google-protobuf"
-  s.version     = "3.12.2"
+  s.version     = "3.12.3"
   git_tag       = "v#{s.version.to_s.sub('.rc.', '-rc')}" # Converts X.Y.Z.rc.N to vX.Y.Z-rcN, used for the git tag
   s.licenses    = ["BSD-3-Clause"]
   s.summary     = "Protocol Buffers"

src/google/protobuf/any.pb.h

@@ -69,7 +69,7 @@ PROTOBUF_NAMESPACE_OPEN
 class PROTOBUF_EXPORT Any PROTOBUF_FINAL :
     public ::PROTOBUF_NAMESPACE_ID::Message /* @@protoc_insertion_point(class_definition:google.protobuf.Any) */ {
  public:
-  inline Any() : Any(nullptr) {};
+  inline Any() : Any(nullptr) {}
   virtual ~Any();
 
   Any(const Any& from);

src/google/protobuf/api.pb.h

@@ -79,7 +79,7 @@ PROTOBUF_NAMESPACE_OPEN
 class PROTOBUF_EXPORT Api PROTOBUF_FINAL :
     public ::PROTOBUF_NAMESPACE_ID::Message /* @@protoc_insertion_point(class_definition:google.protobuf.Api) */ {
  public:
-  inline Api() : Api(nullptr) {};
+  inline Api() : Api(nullptr) {}
   virtual ~Api();
 
   Api(const Api& from);
@@ -332,7 +332,7 @@ class PROTOBUF_EXPORT Api PROTOBUF_FINAL :
 class PROTOBUF_EXPORT Method PROTOBUF_FINAL :
     public ::PROTOBUF_NAMESPACE_ID::Message /* @@protoc_insertion_point(class_definition:google.protobuf.Method) */ {
  public:
-  inline Method() : Method(nullptr) {};
+  inline Method() : Method(nullptr) {}
   virtual ~Method();
 
   Method(const Method& from);
@@ -565,7 +565,7 @@ class PROTOBUF_EXPORT Method PROTOBUF_FINAL :
 class PROTOBUF_EXPORT Mixin PROTOBUF_FINAL :
     public ::PROTOBUF_NAMESPACE_ID::Message /* @@protoc_insertion_point(class_definition:google.protobuf.Mixin) */ {
  public:
-  inline Mixin() : Mixin(nullptr) {};
+  inline Mixin() : Mixin(nullptr) {}
   virtual ~Mixin();
 
   Mixin(const Mixin& from);

src/google/protobuf/compiler/command_line_interface.cc

@@ -1104,6 +1104,7 @@ PopulateSingleSimpleDescriptorDatabase(const std::string& descriptor_set_name) {
 
 bool CommandLineInterface::AllowProto3Optional(
     const FileDescriptor& file) const {
+  // If the --experimental_allow_proto3_optional flag was set, we allow.
   if (allow_proto3_optional_) return true;
 
   // Whitelist all ads protos. Ads is an early adopter of this feature.

src/google/protobuf/compiler/command_line_interface_unittest.cc

@@ -2373,48 +2373,50 @@ TEST_F(CommandLineInterfaceTest, MissingValueAtEndError) {
 }
 
 TEST_F(CommandLineInterfaceTest, Proto3OptionalDisallowed) {
-  CreateTempFile("foo.proto",
+  CreateTempFile("google/foo.proto",
                  "syntax = \"proto3\";\n"
                  "message Foo {\n"
                  "  optional int32 i = 1;\n"
                  "}\n");
 
-  Run("protocol_compiler --proto_path=$tmpdir foo.proto -odescriptor.pb");
+  Run("protocol_compiler --proto_path=$tmpdir google/foo.proto "
+      "-odescriptor.pb");
 
   ExpectErrorSubstring("--experimental_allow_proto3_optional was not set");
 }
 
 TEST_F(CommandLineInterfaceTest, Proto3OptionalDisallowedDescriptor) {
-  CreateTempFile("foo.proto",
+  CreateTempFile("google/foo.proto",
                  "syntax = \"proto3\";\n"
                  "message Foo {\n"
                  "  optional int32 i = 1;\n"
                  "}\n");
 
   Run("protocol_compiler --experimental_allow_proto3_optional "
-      "--proto_path=$tmpdir foo.proto "
+      "--proto_path=$tmpdir google/foo.proto "
       " -o$tmpdir/descriptor.pb");
   ExpectNoErrors();
 
-  Run("protocol_compiler --descriptor_set_in=$tmpdir/descriptor.pb foo.proto "
-      "--test_out=$tmpdir");
+  Run("protocol_compiler --descriptor_set_in=$tmpdir/descriptor.pb"
+      " google/foo.proto --test_out=$tmpdir");
   ExpectErrorSubstring("--experimental_allow_proto3_optional was not set");
 }
 
 TEST_F(CommandLineInterfaceTest, Proto3OptionalDisallowedGenCode) {
-  CreateTempFile("foo.proto",
+  CreateTempFile("google/foo.proto",
                  "syntax = \"proto3\";\n"
                  "message Foo {\n"
                  "  optional int32 i = 1;\n"
                  "}\n");
 
-  Run("protocol_compiler --proto_path=$tmpdir foo.proto --test_out=$tmpdir");
+  Run("protocol_compiler --proto_path=$tmpdir google/foo.proto "
+      "--test_out=$tmpdir");
 
   ExpectErrorSubstring("--experimental_allow_proto3_optional was not set");
 }
 
 TEST_F(CommandLineInterfaceTest, Proto3OptionalDisallowedNoCodegenSupport) {
-  CreateTempFile("foo.proto",
+  CreateTempFile("google/foo.proto",
                  "syntax = \"proto3\";\n"
                  "message Foo {\n"
                  "  optional int32 i = 1;\n"
@@ -2425,7 +2427,7 @@ TEST_F(CommandLineInterfaceTest, Proto3OptionalDisallowedNoCodegenSupport) {
                                      CodeGenerator::FEATURE_PROTO3_OPTIONAL);
 
   Run("protocol_compiler --experimental_allow_proto3_optional "
-      "--proto_path=$tmpdir foo.proto --no_proto3_optional_out=$tmpdir");
+      "--proto_path=$tmpdir google/foo.proto --no_proto3_optional_out=$tmpdir");
 
   ExpectErrorSubstring(
       "code generator --no_proto3_optional_out hasn't been updated to support "
@@ -2433,14 +2435,14 @@ TEST_F(CommandLineInterfaceTest, Proto3OptionalDisallowedNoCodegenSupport) {
 }
 
 TEST_F(CommandLineInterfaceTest, Proto3OptionalAllowWithFlag) {
-  CreateTempFile("foo.proto",
+  CreateTempFile("google/foo.proto",
                  "syntax = \"proto3\";\n"
                  "message Foo {\n"
                  "  optional int32 i = 1;\n"
                  "}\n");
 
   Run("protocol_compiler --experimental_allow_proto3_optional "
-      "--proto_path=$tmpdir foo.proto --test_out=$tmpdir");
+      "--proto_path=$tmpdir google/foo.proto --test_out=$tmpdir");
   ExpectNoErrors();
 }
 

src/google/protobuf/compiler/cpp/cpp_message.cc

@@ -1123,7 +1123,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
   format.Indent();
 
   if (SupportsArenas(descriptor_)) {
-    format("inline $classname$() : $classname$(nullptr) {};\n");
+    format("inline $classname$() : $classname$(nullptr) {}\n");
   } else {
     format("$classname$();\n");
   }

src/google/protobuf/compiler/csharp/csharp_field_base.cc

@@ -161,6 +161,12 @@ void FieldGeneratorBase::GenerateExtensionCode(io::Printer* printer) {
   // and repeated fields need this default is to not generate any code
 }
 
+void FieldGeneratorBase::GenerateParsingCode(io::Printer* printer, bool use_parse_context) {
+  // for some field types the value of "use_parse_context" doesn't matter,
+  // so we fallback to the default implementation.
+  GenerateParsingCode(printer);
+}
+
 void FieldGeneratorBase::AddDeprecatedFlag(io::Printer* printer) {
   if (descriptor_->options().deprecated()) {
     printer->Print("[global::System.ObsoleteAttribute]\n");