Tweaks and more tests for maps

- Change the default message hash code to 1 to be consistent with other code
- Change the empty list/map hash code to 0 as "empty map" is equivalent to "no map"
- Removed map fields from unittest_proto3.proto
- Created map_unittest_proto3.proto which is like map_unittest.proto but proto3-only
- Fixed factory methods in FieldCodec highlighted by using all field types :)
- Added tests for map serialization:
  - Extra fields within entries
  - Entries with value then key
  - Non-contiguous entries for the same map
  - Multiple entries for the same key

Changes to generated code coming in next commit

csharp/generate_protos.sh

@@ -43,10 +43,12 @@ $PROTOC -Isrc --csharp_out=csharp/src/ProtocolBuffers/DescriptorProtos \
 rm src/google/protobuf/descriptor_proto_file.proto
 
 $PROTOC -Isrc --csharp_out=csharp/src/ProtocolBuffers.Test/TestProtos \
+    src/google/protobuf/map_unittest_proto3.proto \
     src/google/protobuf/unittest_proto3.proto \
     src/google/protobuf/unittest_import_proto3.proto \
     src/google/protobuf/unittest_import_public_proto3.proto
 
+
 $PROTOC -Icsharp/protos/extest --csharp_out=csharp/src/ProtocolBuffers.Test/TestProtos \
     csharp/protos/extest/unittest_issues.proto
 

csharp/src/ProtocolBuffers.Test/GeneratedMessageTest.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Configuration;
 using System.IO;
 using Google.Protobuf.TestProtos;
 using NUnit.Framework;
@@ -157,63 +156,204 @@ namespace Google.Protobuf
             Assert.AreEqual(message, parsed);
         }
 
+        // Note that not every map within map_unittest_proto3 is used. They all go through very
+        // similar code paths. The fact that all maps are present is validation that we have codecs
+        // for every type.
         [Test]
         public void RoundTrip_Maps()
         {
-            var message = new TestAllTypes
+            var message = new TestMap
             {
-                MapBoolToEnum = {
-                    { false, TestAllTypes.Types.NestedEnum.BAR},
-                    { true, TestAllTypes.Types.NestedEnum.BAZ}
+                MapBoolBool = {
+                    { false, true },
+                    { true, false }
                 },
-                MapInt32ToBytes = {
+                MapInt32Bytes = {
                     { 5, ByteString.CopyFrom(6, 7, 8) },
                     { 25, ByteString.CopyFrom(1, 2, 3, 4, 5) },
                     { 10, ByteString.Empty }
                 },
-                MapStringToNestedMessage = {
-                    { "", new TestAllTypes.Types.NestedMessage { Bb = 10 } },
-                    { "null value", null },
+                MapInt32ForeignMessage = {
+                    { 0, new ForeignMessage { C = 10 } },
+                    { 5, null },
+                },
+                MapInt32Enum = {
+                    { 1, MapEnum.MAP_ENUM_BAR },
+                    { 2000, MapEnum.MAP_ENUM_FOO }
                 }
             };
 
             byte[] bytes = message.ToByteArray();
-            TestAllTypes parsed = TestAllTypes.Parser.ParseFrom(bytes);
+            TestMap parsed = TestMap.Parser.ParseFrom(bytes);
             Assert.AreEqual(message, parsed);
         }
 
         [Test]
         public void MapWithEmptyEntry()
         {
-            var message = new TestAllTypes
+            var message = new TestMap
             {
-                MapInt32ToBytes = { { 0, ByteString.Empty } }
+                MapInt32Bytes = { { 0, ByteString.Empty } }
             };
 
             byte[] bytes = message.ToByteArray();
-            Assert.AreEqual(3, bytes.Length); // Tag for field entry (2 bytes), length of entry (0; 1 byte)
+            Assert.AreEqual(2, bytes.Length); // Tag for field entry (1 byte), length of entry (0; 1 byte)
 
-            var parsed = TestAllTypes.Parser.ParseFrom(bytes);
-            Assert.AreEqual(1, parsed.MapInt32ToBytes.Count);
-            Assert.AreEqual(ByteString.Empty, parsed.MapInt32ToBytes[0]);
+            var parsed = TestMap.Parser.ParseFrom(bytes);
+            Assert.AreEqual(1, parsed.MapInt32Bytes.Count);
+            Assert.AreEqual(ByteString.Empty, parsed.MapInt32Bytes[0]);
         }
-
+        
         [Test]
         public void MapWithOnlyValue()
         {
             // Hand-craft the stream to contain a single entry with just a value.
             var memoryStream = new MemoryStream();
             var output = CodedOutputStream.CreateInstance(memoryStream);
-            output.WriteTag(TestAllTypes.MapStringToNestedMessageFieldNumber, WireFormat.WireType.LengthDelimited);
-            var nestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 20 };
+            output.WriteTag(TestMap.MapInt32ForeignMessageFieldNumber, WireFormat.WireType.LengthDelimited);
+            var nestedMessage = new ForeignMessage { C = 20 };
             // Size of the entry (tag, size written by WriteMessage, data written by WriteMessage)
             output.WriteRawVarint32((uint)(nestedMessage.CalculateSize() + 3));
             output.WriteTag(2, WireFormat.WireType.LengthDelimited);
             output.WriteMessage(nestedMessage);
             output.Flush();
 
-            var parsed = TestAllTypes.Parser.ParseFrom(memoryStream.ToArray());
-            Assert.AreEqual(nestedMessage, parsed.MapStringToNestedMessage[""]);
+            var parsed = TestMap.Parser.ParseFrom(memoryStream.ToArray());
+            Assert.AreEqual(nestedMessage, parsed.MapInt32ForeignMessage[0]);
+        }
+
+        [Test]
+        public void MapIgnoresExtraFieldsWithinEntryMessages()
+        {
+            // Hand-craft the stream to contain a single entry with three fields
+            var memoryStream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(memoryStream);
+
+            output.WriteTag(TestMap.MapInt32Int32FieldNumber, WireFormat.WireType.LengthDelimited);
+
+            var key = 10; // Field 1 
+            var value = 20; // Field 2
+            var extra = 30; // Field 3
+
+            // Each field can be represented in a single byte, with a single byte tag.
+            // Total message size: 6 bytes.
+            output.WriteRawVarint32(6);
+            output.WriteTag(1, WireFormat.WireType.Varint);
+            output.WriteInt32(key);
+            output.WriteTag(2, WireFormat.WireType.Varint);
+            output.WriteInt32(value);
+            output.WriteTag(3, WireFormat.WireType.Varint);
+            output.WriteInt32(extra);
+            output.Flush();
+
+            var parsed = TestMap.Parser.ParseFrom(memoryStream.ToArray());
+            Assert.AreEqual(value, parsed.MapInt32Int32[key]);
+        }
+
+        [Test]
+        public void MapFieldOrderIsIrrelevant()
+        {
+            var memoryStream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(memoryStream);
+
+            output.WriteTag(TestMap.MapInt32Int32FieldNumber, WireFormat.WireType.LengthDelimited);
+
+            var key = 10;
+            var value = 20;
+
+            // Each field can be represented in a single byte, with a single byte tag.
+            // Total message size: 4 bytes.
+            output.WriteRawVarint32(4);
+            output.WriteTag(2, WireFormat.WireType.Varint);
+            output.WriteInt32(value);
+            output.WriteTag(1, WireFormat.WireType.Varint);
+            output.WriteInt32(key);
+            output.Flush();
+
+            var parsed = TestMap.Parser.ParseFrom(memoryStream.ToArray());
+            Assert.AreEqual(value, parsed.MapInt32Int32[key]);
+        }
+
+        [Test]
+        public void MapNonContiguousEntries()
+        {
+            var memoryStream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(memoryStream);
+
+            // Message structure:
+            // Entry for MapInt32Int32
+            // Entry for MapStringString
+            // Entry for MapInt32Int32
+
+            // First entry
+            var key1 = 10;
+            var value1 = 20;
+            output.WriteTag(TestMap.MapInt32Int32FieldNumber, WireFormat.WireType.LengthDelimited);
+            output.WriteRawVarint32(4);
+            output.WriteTag(1, WireFormat.WireType.Varint);
+            output.WriteInt32(key1);
+            output.WriteTag(2, WireFormat.WireType.Varint);
+            output.WriteInt32(value1);
+
+            // Second entry
+            var key2 = "a";
+            var value2 = "b";
+            output.WriteTag(TestMap.MapStringStringFieldNumber, WireFormat.WireType.LengthDelimited);
+            output.WriteRawVarint32(6); // 3 bytes per entry: tag, size, character
+            output.WriteTag(1, WireFormat.WireType.LengthDelimited);
+            output.WriteString(key2);
+            output.WriteTag(2, WireFormat.WireType.LengthDelimited);
+            output.WriteString(value2);
+
+            // Third entry
+            var key3 = 15;
+            var value3 = 25;
+            output.WriteTag(TestMap.MapInt32Int32FieldNumber, WireFormat.WireType.LengthDelimited);
+            output.WriteRawVarint32(4);
+            output.WriteTag(1, WireFormat.WireType.Varint);
+            output.WriteInt32(key3);
+            output.WriteTag(2, WireFormat.WireType.Varint);
+            output.WriteInt32(value3);
+
+            output.Flush();
+            var parsed = TestMap.Parser.ParseFrom(memoryStream.ToArray());
+            var expected = new TestMap
+            {
+                MapInt32Int32 = { { key1, value1 }, { key3, value3 } },
+                MapStringString = { { key2, value2 } }
+            };
+            Assert.AreEqual(expected, parsed);
+        }
+
+        [Test]
+        public void DuplicateKeys_LastEntryWins()
+        {
+            var memoryStream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(memoryStream);
+
+            var key = 10;
+            var value1 = 20;
+            var value2 = 30;
+
+            // First entry
+            output.WriteTag(TestMap.MapInt32Int32FieldNumber, WireFormat.WireType.LengthDelimited);
+            output.WriteRawVarint32(4);
+            output.WriteTag(1, WireFormat.WireType.Varint);
+            output.WriteInt32(key);
+            output.WriteTag(2, WireFormat.WireType.Varint);
+            output.WriteInt32(value1);
+
+            // Second entry - same key, different value
+            output.WriteTag(TestMap.MapInt32Int32FieldNumber, WireFormat.WireType.LengthDelimited);
+            output.WriteRawVarint32(4);
+            output.WriteTag(1, WireFormat.WireType.Varint);
+            output.WriteInt32(key);
+            output.WriteTag(2, WireFormat.WireType.Varint);
+            output.WriteInt32(value2);
+            output.Flush();
+
+            var parsed = TestMap.Parser.ParseFrom(memoryStream.ToArray());
+            Assert.AreEqual(value2, parsed.MapInt32Int32[key]);
         }
 
         [Test]

csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj

@@ -78,6 +78,7 @@
     <Compile Include="GeneratedMessageTest.cs" />
     <Compile Include="Collections\MapFieldTest.cs" />
     <Compile Include="Collections\RepeatedFieldTest.cs" />
+    <Compile Include="TestProtos\MapUnittestProto3.cs" />
     <Compile Include="TestProtos\UnittestImportProto3.cs" />
     <Compile Include="TestProtos\UnittestImportPublicProto3.cs" />
     <Compile Include="TestProtos\UnittestIssues.cs" />

csharp/src/ProtocolBuffers/Collections/MapField.cs

@@ -261,7 +261,7 @@ namespace Google.Protobuf.Collections
         public override int GetHashCode()
         {
             var valueComparer = EqualityComparer<TValue>.Default;
-            int hash = 19;
+            int hash = 0;
             foreach (var pair in list)
             {
                 hash ^= pair.Key.GetHashCode() * 31 + valueComparer.GetHashCode(pair.Value);
@@ -380,7 +380,6 @@ namespace Google.Protobuf.Collections
                 private readonly Codec codec;
                 internal TKey Key { get; set; }
                 internal TValue Value { get; set; }
-                internal int Size { get; set; }
 
                 internal MessageAdapter(Codec codec)
                 {

csharp/src/ProtocolBuffers/Collections/RepeatedField.cs

@@ -193,7 +193,7 @@ namespace Google.Protobuf.Collections
 
         public override int GetHashCode()
         {
-            int hash = 23;
+            int hash = 0;
             for (int i = 0; i < count; i++)
             {
                 hash = hash * 31 + array[i].GetHashCode();

csharp/src/ProtocolBuffers/FieldCodec.cs

@@ -33,11 +33,16 @@ namespace Google.Protobuf
             return new FieldCodec<int>(input => input.ReadSInt32(), (output, value) => output.WriteSInt32(value), CodedOutputStream.ComputeSInt32Size, tag);
         }
 
-        public static FieldCodec<uint> ForFixedInt32(uint tag)
+        public static FieldCodec<uint> ForFixed32(uint tag)
         {
             return new FieldCodec<uint>(input => input.ReadFixed32(), (output, value) => output.WriteFixed32(value), CodedOutputStream.ComputeFixed32Size, tag);
         }
 
+        public static FieldCodec<int> ForSFixed32(uint tag)
+        {
+            return new FieldCodec<int>(input => input.ReadSFixed32(), (output, value) => output.WriteSFixed32(value), CodedOutputStream.ComputeSFixed32Size, tag);
+        }
+
         public static FieldCodec<uint> ForUInt32(uint tag)
         {
             return new FieldCodec<uint>(input => input.ReadUInt32(), (output, value) => output.WriteUInt32(value), CodedOutputStream.ComputeUInt32Size, tag);
@@ -53,11 +58,16 @@ namespace Google.Protobuf
             return new FieldCodec<long>(input => input.ReadSInt64(), (output, value) => output.WriteSInt64(value), CodedOutputStream.ComputeSInt64Size, tag);
         }
 
-        public static FieldCodec<ulong> ForFixedInt64(uint tag)
+        public static FieldCodec<ulong> ForFixed64(uint tag)
         {
             return new FieldCodec<ulong>(input => input.ReadFixed64(), (output, value) => output.WriteFixed64(value), CodedOutputStream.ComputeFixed64Size, tag);
         }
 
+        public static FieldCodec<long> ForSFixed64(uint tag)
+        {
+            return new FieldCodec<long>(input => input.ReadSFixed64(), (output, value) => output.WriteSFixed64(value), CodedOutputStream.ComputeSFixed64Size, tag);
+        }
+
         public static FieldCodec<ulong> ForUInt64(uint tag)
         {
             return new FieldCodec<ulong>(input => input.ReadUInt64(), (output, value) => output.WriteUInt64(value), CodedOutputStream.ComputeUInt64Size, tag);

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

@@ -408,7 +408,7 @@ void MessageGenerator::GenerateFrameworkMethods(io::Printer* printer) {
     // Start with a non-zero value to easily distinguish between null and "empty" messages.
     printer->Print(
         "public override int GetHashCode() {\n"
-        "  int hash = 17;\n");
+        "  int hash = 1;\n");
     printer->Indent();
     for (int i = 0; i < descriptor_->field_count(); i++) {
         scoped_ptr<FieldGeneratorBase> generator(

src/google/protobuf/map_unittest_proto3.proto

@@ -0,0 +1,120 @@
+// 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.
+
+// This file is mostly equivalent to map_unittest.proto, but imports
+// unittest_proto3.proto instead of unittest.proto, so that it only
+// uses proto3 messages. This makes it suitable for testing
+// implementations which only support proto3.
+// The TestRequiredMessageMap message has been removed as there are no
+// required fields in proto3.
+syntax = "proto3";
+
+option cc_enable_arenas = true;
+option csharp_namespace = "Google.Protobuf.TestProtos";
+
+import "google/protobuf/unittest_proto3.proto";
+
+// We don't put this in a package within proto2 because we need to make sure
+// that the generated code doesn't depend on being in the proto2 namespace.
+// In map_test_util.h we do "using namespace unittest = protobuf_unittest".
+package protobuf_unittest;
+
+// Tests maps.
+message TestMap {
+  map<int32   , int32   > map_int32_int32       = 1;
+  map<int64   , int64   > map_int64_int64       = 2;
+  map<uint32  , uint32  > map_uint32_uint32     = 3;
+  map<uint64  , uint64  > map_uint64_uint64     = 4;
+  map<sint32  , sint32  > map_sint32_sint32     = 5;
+  map<sint64  , sint64  > map_sint64_sint64     = 6;
+  map<fixed32 , fixed32 > map_fixed32_fixed32   = 7;
+  map<fixed64 , fixed64 > map_fixed64_fixed64   = 8;
+  map<sfixed32, sfixed32> map_sfixed32_sfixed32 = 9;
+  map<sfixed64, sfixed64> map_sfixed64_sfixed64 = 10;
+  map<int32   , float   > map_int32_float       = 11;
+  map<int32   , double  > map_int32_double      = 12;
+  map<bool    , bool    > map_bool_bool         = 13;
+  map<string  , string  > map_string_string     = 14;
+  map<int32   , bytes   > map_int32_bytes       = 15;
+  map<int32   , MapEnum > map_int32_enum        = 16;
+  map<int32   , ForeignMessage> map_int32_foreign_message = 17;
+}
+
+message TestMapSubmessage {
+  TestMap test_map = 1;
+}
+
+message TestMessageMap {
+  map<int32, TestAllTypes> map_int32_message = 1;
+}
+
+// Two map fields share the same entry default instance.
+message TestSameTypeMap {
+  map<int32, int32> map1 = 1;
+  map<int32, int32> map2 = 2;
+}
+
+enum MapEnum {
+  MAP_ENUM_FOO = 0;
+  MAP_ENUM_BAR = 1;
+  MAP_ENUM_BAZ = 2;
+}
+
+message TestArenaMap {
+  map<int32   , int32   > map_int32_int32       = 1;
+  map<int64   , int64   > map_int64_int64       = 2;
+  map<uint32  , uint32  > map_uint32_uint32     = 3;
+  map<uint64  , uint64  > map_uint64_uint64     = 4;
+  map<sint32  , sint32  > map_sint32_sint32     = 5;
+  map<sint64  , sint64  > map_sint64_sint64     = 6;
+  map<fixed32 , fixed32 > map_fixed32_fixed32   = 7;
+  map<fixed64 , fixed64 > map_fixed64_fixed64   = 8;
+  map<sfixed32, sfixed32> map_sfixed32_sfixed32 = 9;
+  map<sfixed64, sfixed64> map_sfixed64_sfixed64 = 10;
+  map<int32   , float   > map_int32_float       = 11;
+  map<int32   , double  > map_int32_double      = 12;
+  map<bool    , bool    > map_bool_bool         = 13;
+  map<int32   , MapEnum > map_int32_enum        = 14;
+  map<int32   , ForeignMessage> map_int32_foreign_message = 15;
+}
+
+// Previously, message containing enum called Type cannot be used as value of
+// map field.
+message MessageContainingEnumCalledType {
+  enum Type {
+    TYPE_FOO = 0;
+  }
+  map<int32, MessageContainingEnumCalledType> type = 1;
+}
+
+// Previously, message cannot contain map field called "entry".
+message MessageContainingMapCalledEntry {
+  map<int32, int32> entry = 1;
+}

src/google/protobuf/unittest_proto3.proto

@@ -140,11 +140,6 @@ message TestAllTypes {
     string oneof_string = 113;
     bytes oneof_bytes = 114;
   }
-  
-  // Sample maps
-  map<string, NestedMessage> map_string_to_nested_message = 200;
-  map<int32, bytes> map_int32_to_bytes = 201;
-  map<bool, NestedEnum> map_bool_to_enum = 202;
 }
 
 // This proto includes a recusively nested message.