Add tests for extension accessor

csharp/src/Google.Protobuf.Test/Reflection/FieldAccessTest.cs

@@ -31,10 +31,13 @@
 #endregion
 
 using Google.Protobuf.TestProtos;
+using Proto2 = Google.Protobuf.TestProtos.Proto2;
 using NUnit.Framework;
 using System;
 using System.Collections;
-using System.Collections.Generic;
+using System.Collections.Generic;
+
+using static Google.Protobuf.TestProtos.Proto2.UnittestExtensions;
 
 namespace Google.Protobuf.Reflection
 {
@@ -44,36 +47,36 @@ namespace Google.Protobuf.Reflection
         public void GetValue()
         {
             var message = SampleMessages.CreateFullTestAllTypes();
-            var fields = TestAllTypes.Descriptor.Fields;
-            Assert.AreEqual(message.SingleBool, fields[TestAllTypes.SingleBoolFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleBytes, fields[TestAllTypes.SingleBytesFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleDouble, fields[TestAllTypes.SingleDoubleFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleFixed32, fields[TestAllTypes.SingleFixed32FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleFixed64, fields[TestAllTypes.SingleFixed64FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleFloat, fields[TestAllTypes.SingleFloatFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleForeignEnum, fields[TestAllTypes.SingleForeignEnumFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleForeignMessage, fields[TestAllTypes.SingleForeignMessageFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleImportEnum, fields[TestAllTypes.SingleImportEnumFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleImportMessage, fields[TestAllTypes.SingleImportMessageFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleInt32, fields[TestAllTypes.SingleInt32FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleInt64, fields[TestAllTypes.SingleInt64FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleNestedEnum, fields[TestAllTypes.SingleNestedEnumFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleNestedMessage, fields[TestAllTypes.SingleNestedMessageFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SinglePublicImportMessage, fields[TestAllTypes.SinglePublicImportMessageFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleSint32, fields[TestAllTypes.SingleSint32FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleSint64, fields[TestAllTypes.SingleSint64FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleString, fields[TestAllTypes.SingleStringFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleSfixed32, fields[TestAllTypes.SingleSfixed32FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleSfixed64, fields[TestAllTypes.SingleSfixed64FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleUint32, fields[TestAllTypes.SingleUint32FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.SingleUint64, fields[TestAllTypes.SingleUint64FieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.OneofBytes, fields[TestAllTypes.OneofBytesFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.OneofString, fields[TestAllTypes.OneofStringFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.OneofNestedMessage, fields[TestAllTypes.OneofNestedMessageFieldNumber].Accessor.GetValue(message));
-            Assert.AreEqual(message.OneofUint32, fields[TestAllTypes.OneofUint32FieldNumber].Accessor.GetValue(message));
+            var fields = TestProtos.TestAllTypes.Descriptor.Fields;
+            Assert.AreEqual(message.SingleBool, fields[TestProtos.TestAllTypes.SingleBoolFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleBytes, fields[TestProtos.TestAllTypes.SingleBytesFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleDouble, fields[TestProtos.TestAllTypes.SingleDoubleFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleFixed32, fields[TestProtos.TestAllTypes.SingleFixed32FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleFixed64, fields[TestProtos.TestAllTypes.SingleFixed64FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleFloat, fields[TestProtos.TestAllTypes.SingleFloatFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleForeignEnum, fields[TestProtos.TestAllTypes.SingleForeignEnumFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleForeignMessage, fields[TestProtos.TestAllTypes.SingleForeignMessageFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleImportEnum, fields[TestProtos.TestAllTypes.SingleImportEnumFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleImportMessage, fields[TestProtos.TestAllTypes.SingleImportMessageFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleInt32, fields[TestProtos.TestAllTypes.SingleInt32FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleInt64, fields[TestProtos.TestAllTypes.SingleInt64FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleNestedEnum, fields[TestProtos.TestAllTypes.SingleNestedEnumFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleNestedMessage, fields[TestProtos.TestAllTypes.SingleNestedMessageFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SinglePublicImportMessage, fields[TestProtos.TestAllTypes.SinglePublicImportMessageFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleSint32, fields[TestProtos.TestAllTypes.SingleSint32FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleSint64, fields[TestProtos.TestAllTypes.SingleSint64FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleString, fields[TestProtos.TestAllTypes.SingleStringFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleSfixed32, fields[TestProtos.TestAllTypes.SingleSfixed32FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleSfixed64, fields[TestProtos.TestAllTypes.SingleSfixed64FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleUint32, fields[TestProtos.TestAllTypes.SingleUint32FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.SingleUint64, fields[TestProtos.TestAllTypes.SingleUint64FieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.OneofBytes, fields[TestProtos.TestAllTypes.OneofBytesFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.OneofString, fields[TestProtos.TestAllTypes.OneofStringFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.OneofNestedMessage, fields[TestProtos.TestAllTypes.OneofNestedMessageFieldNumber].Accessor.GetValue(message));
+            Assert.AreEqual(message.OneofUint32, fields[TestProtos.TestAllTypes.OneofUint32FieldNumber].Accessor.GetValue(message));
 
             // Just one example for repeated fields - they're all just returning the list
-            var list = (IList) fields[TestAllTypes.RepeatedInt32FieldNumber].Accessor.GetValue(message);
+            var list = (IList) fields[TestProtos.TestAllTypes.RepeatedInt32FieldNumber].Accessor.GetValue(message);
             Assert.AreEqual(message.RepeatedInt32, list);
             Assert.AreEqual(message.RepeatedInt32[0], list[0]); // Just in case there was any doubt...
 
@@ -85,18 +88,27 @@ namespace Google.Protobuf.Reflection
             Assert.AreEqual("value1", dictionary["key1"]);
         }
 
+        [Test]
+        public void GetExtensionValue()
+        {
+            var message = SampleMessages.CreateFullTestAllExtensions();
+
+            // test that the reflector works, since the reflector just runs through IExtendableMessage
+            Assert.AreEqual(message.GetExtension(OptionalBoolExtension), Proto2.TestAllExtensions.Descriptor.FindFieldByNumber(OptionalBoolExtension.FieldNumber).Accessor.GetValue(message));
+        }
+
         [Test]
         public void Clear()
         {
             var message = SampleMessages.CreateFullTestAllTypes();
-            var fields = TestAllTypes.Descriptor.Fields;
-            fields[TestAllTypes.SingleBoolFieldNumber].Accessor.Clear(message);
-            fields[TestAllTypes.SingleInt32FieldNumber].Accessor.Clear(message);
-            fields[TestAllTypes.SingleStringFieldNumber].Accessor.Clear(message);
-            fields[TestAllTypes.SingleBytesFieldNumber].Accessor.Clear(message);
-            fields[TestAllTypes.SingleForeignEnumFieldNumber].Accessor.Clear(message);
-            fields[TestAllTypes.SingleForeignMessageFieldNumber].Accessor.Clear(message);
-            fields[TestAllTypes.RepeatedDoubleFieldNumber].Accessor.Clear(message);
+            var fields = TestProtos.TestAllTypes.Descriptor.Fields;
+            fields[TestProtos.TestAllTypes.SingleBoolFieldNumber].Accessor.Clear(message);
+            fields[TestProtos.TestAllTypes.SingleInt32FieldNumber].Accessor.Clear(message);
+            fields[TestProtos.TestAllTypes.SingleStringFieldNumber].Accessor.Clear(message);
+            fields[TestProtos.TestAllTypes.SingleBytesFieldNumber].Accessor.Clear(message);
+            fields[TestProtos.TestAllTypes.SingleForeignEnumFieldNumber].Accessor.Clear(message);
+            fields[TestProtos.TestAllTypes.SingleForeignMessageFieldNumber].Accessor.Clear(message);
+            fields[TestProtos.TestAllTypes.RepeatedDoubleFieldNumber].Accessor.Clear(message);
 
             var expected = new TestAllTypes(SampleMessages.CreateFullTestAllTypes())
             {
@@ -123,14 +135,14 @@ namespace Google.Protobuf.Reflection
         {
             // Just a sample (primitives, messages, enums, strings, byte strings)
             var message = SampleMessages.CreateFullTestAllTypes();
-            var fields = TestAllTypes.Descriptor.Fields;
-            fields[TestAllTypes.SingleBoolFieldNumber].Accessor.SetValue(message, false);
-            fields[TestAllTypes.SingleInt32FieldNumber].Accessor.SetValue(message, 500);
-            fields[TestAllTypes.SingleStringFieldNumber].Accessor.SetValue(message, "It's a string");
-            fields[TestAllTypes.SingleBytesFieldNumber].Accessor.SetValue(message, ByteString.CopyFrom(99, 98, 97));
-            fields[TestAllTypes.SingleForeignEnumFieldNumber].Accessor.SetValue(message, ForeignEnum.ForeignFoo);
-            fields[TestAllTypes.SingleForeignMessageFieldNumber].Accessor.SetValue(message, new ForeignMessage { C = 12345 });
-            fields[TestAllTypes.SingleDoubleFieldNumber].Accessor.SetValue(message, 20150701.5);
+            var fields = TestProtos.TestAllTypes.Descriptor.Fields;
+            fields[TestProtos.TestAllTypes.SingleBoolFieldNumber].Accessor.SetValue(message, false);
+            fields[TestProtos.TestAllTypes.SingleInt32FieldNumber].Accessor.SetValue(message, 500);
+            fields[TestProtos.TestAllTypes.SingleStringFieldNumber].Accessor.SetValue(message, "It's a string");
+            fields[TestProtos.TestAllTypes.SingleBytesFieldNumber].Accessor.SetValue(message, ByteString.CopyFrom(99, 98, 97));
+            fields[TestProtos.TestAllTypes.SingleForeignEnumFieldNumber].Accessor.SetValue(message, ForeignEnum.ForeignFoo);
+            fields[TestProtos.TestAllTypes.SingleForeignMessageFieldNumber].Accessor.SetValue(message, new ForeignMessage { C = 12345 });
+            fields[TestProtos.TestAllTypes.SingleDoubleFieldNumber].Accessor.SetValue(message, 20150701.5);
 
             var expected = new TestAllTypes(SampleMessages.CreateFullTestAllTypes())
             {
@@ -151,7 +163,7 @@ namespace Google.Protobuf.Reflection
         {
             IMessage message = SampleMessages.CreateFullTestAllTypes();
             var fields = message.Descriptor.Fields;
-            Assert.Throws<InvalidCastException>(() => fields[TestAllTypes.SingleBoolFieldNumber].Accessor.SetValue(message, "This isn't a bool"));
+            Assert.Throws<InvalidCastException>(() => fields[TestProtos.TestAllTypes.SingleBoolFieldNumber].Accessor.SetValue(message, "This isn't a bool"));
         }
 
         [Test]
@@ -167,7 +179,7 @@ namespace Google.Protobuf.Reflection
         {
             IMessage message = SampleMessages.CreateFullTestAllTypes();
             var fields = message.Descriptor.Fields;
-            Assert.Throws<InvalidOperationException>(() => fields[TestAllTypes.RepeatedDoubleFieldNumber].Accessor.SetValue(message, new double[10]));
+            Assert.Throws<InvalidOperationException>(() => fields[TestProtos.TestAllTypes.RepeatedDoubleFieldNumber].Accessor.SetValue(message, new double[10]));
         }
 
         [Test]
@@ -175,42 +187,42 @@ namespace Google.Protobuf.Reflection
         {
             IMessage message = SampleMessages.CreateFullTestAllTypes();
             var fields = message.Descriptor.Fields;
-            Assert.Throws<InvalidCastException>(() => fields[TestAllTypes.SingleBoolFieldNumber].Accessor.GetValue(new TestMap()));
+            Assert.Throws<InvalidCastException>(() => fields[TestProtos.TestAllTypes.SingleBoolFieldNumber].Accessor.GetValue(new TestMap()));
         }
 
         [Test]
         public void Oneof()
         {
             var message = new TestAllTypes();
-            var descriptor = TestAllTypes.Descriptor;
+            var descriptor = TestProtos.TestAllTypes.Descriptor;
             Assert.AreEqual(1, descriptor.Oneofs.Count);
             var oneof = descriptor.Oneofs[0];
             Assert.AreEqual("oneof_field", oneof.Name);
             Assert.IsNull(oneof.Accessor.GetCaseFieldDescriptor(message));
 
             message.OneofString = "foo";
-            Assert.AreSame(descriptor.Fields[TestAllTypes.OneofStringFieldNumber], oneof.Accessor.GetCaseFieldDescriptor(message));
+            Assert.AreSame(descriptor.Fields[TestProtos.TestAllTypes.OneofStringFieldNumber], oneof.Accessor.GetCaseFieldDescriptor(message));
 
             message.OneofUint32 = 10;
-            Assert.AreSame(descriptor.Fields[TestAllTypes.OneofUint32FieldNumber], oneof.Accessor.GetCaseFieldDescriptor(message));
+            Assert.AreSame(descriptor.Fields[TestProtos.TestAllTypes.OneofUint32FieldNumber], oneof.Accessor.GetCaseFieldDescriptor(message));
 
             oneof.Accessor.Clear(message);
-            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.None, message.OneofFieldCase);
+            Assert.AreEqual(TestProtos.TestAllTypes.OneofFieldOneofCase.None, message.OneofFieldCase);
         }
 
         [Test]
         public void FieldDescriptor_ByName()
         {
-            var descriptor = TestAllTypes.Descriptor;
+            var descriptor = TestProtos.TestAllTypes.Descriptor;
             Assert.AreSame(
-                descriptor.Fields[TestAllTypes.SingleBoolFieldNumber],
+                descriptor.Fields[TestProtos.TestAllTypes.SingleBoolFieldNumber],
                 descriptor.Fields["single_bool"]);
         }
 
         [Test]
         public void FieldDescriptor_NotFound()
         {
-            var descriptor = TestAllTypes.Descriptor;
+            var descriptor = TestProtos.TestAllTypes.Descriptor;
             Assert.Throws<KeyNotFoundException>(() => descriptor.Fields[999999].ToString());
             Assert.Throws<KeyNotFoundException>(() => descriptor.Fields["not found"].ToString());
         }

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

@@ -32,7 +32,9 @@
 
 using System;
 using Google.Protobuf.TestProtos;
-using Proto2 = Google.Protobuf.TestProtos.Proto2;
+using Proto2 = Google.Protobuf.TestProtos.Proto2;
+
+using static Google.Protobuf.TestProtos.Proto2.UnittestExtensions;
 
 namespace Google.Protobuf
 {
@@ -61,7 +63,7 @@ namespace Google.Protobuf
                 SingleImportMessage = new ImportMessage { D = 20 },
                 SingleInt32 = 100,
                 SingleInt64 = 3210987654321,
-                SingleNestedEnum = TestAllTypes.Types.NestedEnum.Foo,
+                SingleNestedEnum = TestProtos.TestAllTypes.Types.NestedEnum.Foo,
                 SingleNestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 35 },
                 SinglePublicImportMessage = new PublicImportMessage { E = 54 },
                 SingleSfixed32 = -123,
@@ -83,7 +85,7 @@ namespace Google.Protobuf
                 RepeatedImportMessage = { new ImportMessage { D = 20 }, new ImportMessage { D = 25 } },
                 RepeatedInt32 = { 100, 200 },
                 RepeatedInt64 = { 3210987654321, Int64.MaxValue },
-                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.Foo, TestAllTypes.Types.NestedEnum.Neg },
+                RepeatedNestedEnum = { TestProtos.TestAllTypes.Types.NestedEnum.Foo, TestProtos.TestAllTypes.Types.NestedEnum.Neg },
                 RepeatedNestedMessage = { new TestAllTypes.Types.NestedMessage { Bb = 35 }, new TestAllTypes.Types.NestedMessage { Bb = 10 } },
                 RepeatedPublicImportMessage = { new PublicImportMessage { E = 54 }, new PublicImportMessage { E = -1 } },
                 RepeatedSfixed32 = { -123, 123 },
@@ -149,5 +151,57 @@ namespace Google.Protobuf
                 OneofString = "Oneof string"
             };
         }
+
+        public static Proto2.TestAllExtensions CreateFullTestAllExtensions()
+        {
+            var message = new Proto2.TestAllExtensions();
+            message.SetExtension(OptionalBoolExtension, true);
+            message.SetExtension(OptionalBytesExtension, ByteString.CopyFrom(1, 2, 3, 4));
+            message.SetExtension(OptionalDoubleExtension, 23.5);
+            message.SetExtension(OptionalFixed32Extension, 23u);
+            message.SetExtension(OptionalFixed64Extension, 1234567890123u);
+            message.SetExtension(OptionalFloatExtension, 12.25f);
+            message.SetExtension(OptionalForeignEnumExtension, Proto2.ForeignEnum.ForeignBar);
+            message.SetExtension(OptionalForeignMessageExtension, new Proto2.ForeignMessage { C = 10 });
+            message.SetExtension(OptionalImportEnumExtension, Proto2.ImportEnum.ImportBaz);
+            message.SetExtension(OptionalImportMessageExtension, new Proto2.ImportMessage { D = 20 });
+            message.SetExtension(OptionalInt32Extension, 100);
+            message.SetExtension(OptionalInt64Extension, 3210987654321);
+            message.SetExtension(OptionalNestedEnumExtension, Proto2.TestAllTypes.Types.NestedEnum.Foo);
+            message.SetExtension(OptionalNestedMessageExtension, new Proto2.TestAllTypes.Types.NestedMessage { Bb = 35 });
+            message.SetExtension(OptionalPublicImportMessageExtension, new Proto2.PublicImportMessage { E = 54 });
+            message.SetExtension(OptionalSfixed32Extension, -123);
+            message.SetExtension(OptionalSfixed64Extension, -12345678901234);
+            message.SetExtension(OptionalSint32Extension, -456);
+            message.SetExtension(OptionalSint64Extension, -12345678901235);
+            message.SetExtension(OptionalStringExtension, "test");
+            message.SetExtension(OptionalUint32Extension, UInt32.MaxValue);
+            message.SetExtension(OptionalUint64Extension, UInt64.MaxValue);
+            message.SetExtension(OptionalGroupExtension, new Proto2.OptionalGroup_extension { A = 10 });
+            message.GetOrRegisterExtension(RepeatedBoolExtension).AddRange(new[] { true, false });
+            message.GetOrRegisterExtension(RepeatedBytesExtension).AddRange(new[] { ByteString.CopyFrom(1, 2, 3, 4), ByteString.CopyFrom(5, 6), ByteString.CopyFrom(new byte[1000]) });
+            message.GetOrRegisterExtension(RepeatedDoubleExtension).AddRange(new[] { -12.25, 23.5 });
+            message.GetOrRegisterExtension(RepeatedFixed32Extension).AddRange(new[] { UInt32.MaxValue, 23u });
+            message.GetOrRegisterExtension(RepeatedFixed64Extension).AddRange(new[] { UInt64.MaxValue, 1234567890123ul });
+            message.GetOrRegisterExtension(RepeatedFloatExtension).AddRange(new[] { 100f, 12.25f });
+            message.GetOrRegisterExtension(RepeatedForeignEnumExtension).AddRange(new[] { Proto2.ForeignEnum.ForeignFoo, Proto2.ForeignEnum.ForeignBar });
+            message.GetOrRegisterExtension(RepeatedForeignMessageExtension).AddRange(new[] { new Proto2.ForeignMessage(), new Proto2.ForeignMessage { C = 10 } });
+            message.GetOrRegisterExtension(RepeatedImportEnumExtension).AddRange(new[] { Proto2.ImportEnum.ImportBaz, Proto2.ImportEnum.ImportFoo });
+            message.GetOrRegisterExtension(RepeatedImportMessageExtension).AddRange(new[] { new Proto2.ImportMessage { D = 20 }, new Proto2.ImportMessage { D = 25 } });
+            message.GetOrRegisterExtension(RepeatedInt32Extension).AddRange(new[] { 100, 200 });
+            message.GetOrRegisterExtension(RepeatedInt64Extension).AddRange(new[] { 3210987654321, Int64.MaxValue });
+            message.GetOrRegisterExtension(RepeatedNestedEnumExtension).AddRange(new[] { Proto2.TestAllTypes.Types.NestedEnum.Foo, Proto2.TestAllTypes.Types.NestedEnum.Neg });
+            message.GetOrRegisterExtension(RepeatedNestedMessageExtension).AddRange(new[] { new Proto2.TestAllTypes.Types.NestedMessage { Bb = 35 }, new Proto2.TestAllTypes.Types.NestedMessage { Bb = 10 } });
+            message.GetOrRegisterExtension(RepeatedSfixed32Extension).AddRange(new[] { -123, 123 });
+            message.GetOrRegisterExtension(RepeatedSfixed64Extension).AddRange(new[] { -12345678901234, 12345678901234 });
+            message.GetOrRegisterExtension(RepeatedSint32Extension).AddRange(new[] { -456, 100 });
+            message.GetOrRegisterExtension(RepeatedSint64Extension).AddRange(new[] { -12345678901235, 123 });
+            message.GetOrRegisterExtension(RepeatedStringExtension).AddRange(new[] { "foo", "bar" });
+            message.GetOrRegisterExtension(RepeatedUint32Extension).AddRange(new[] { UInt32.MaxValue, UInt32.MinValue });
+            message.GetOrRegisterExtension(RepeatedUint64Extension).AddRange(new[] { UInt64.MaxValue, UInt32.MinValue });
+            message.GetOrRegisterExtension(RepeatedGroupExtension).AddRange(new[] { new Proto2.RepeatedGroup_extension { A = 10 }, new Proto2.RepeatedGroup_extension { A = 20 } });
+            message.SetExtension(OneofStringExtension, "Oneof string");
+            return message;
+        }
     }
 }

csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs

@@ -380,7 +380,12 @@ namespace Google.Protobuf.Reflection
         }
 
         private IFieldAccessor CreateAccessor()
-        {
+        {
+            if (Extension != null)
+            {
+                return new ExtensionAccessor(this);
+            }
+
             // If we're given no property name, that's because we really don't want an accessor.
             // This could be because it's a map message, or it could be that we're loading a FileDescriptor dynamically.
             // TODO: Support dynamic messages.
@@ -389,10 +394,6 @@ namespace Google.Protobuf.Reflection
                 return null;
             }
 
-            if (Extension != null)
-            {
-                return new ExtensionAccessor(this);
-            }
             var property = ContainingType.ClrType.GetProperty(propertyName);
             if (property == null)
             {

csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs

@@ -123,7 +123,7 @@ namespace Google.Protobuf.Reflection
         /// the type that declares the method, and the second argument to the first parameter type of the method.
         /// </summary>
         internal static IExtensionReflectionHelper CreateExtensionHelper(Extension extension) =>
-            (IExtensionReflectionHelper)Activator.CreateInstance(typeof(ExtensionReflectionHelper<,>).MakeGenericType(extension.TargetType, extension.GetType().GenericTypeArguments[1]));
+            (IExtensionReflectionHelper)Activator.CreateInstance(typeof(ExtensionReflectionHelper<,>).MakeGenericType(extension.TargetType, extension.GetType().GenericTypeArguments[1]), extension);
 
         /// <summary>
         /// Creates a reflection helper for the given type arguments. Currently these are created on demand