public void TestFieldPresenceReflection()
{
MessageDescriptor descriptor = TestAllTypes.Descriptor;
FieldDescriptor optionalInt32Field = descriptor.FindFieldByName("optional_int32");
FieldDescriptor optionalStringField = descriptor.FindFieldByName("optional_string");
FieldDescriptor optionalBytesField = descriptor.FindFieldByName("optional_bytes");
FieldDescriptor optionalNestedEnumField = descriptor.FindFieldByName("optional_nested_enum");
TestAllTypes message = TestAllTypes.CreateBuilder().Build();
Assert.IsFalse(message.HasField(optionalInt32Field));
Assert.IsFalse(message.HasField(optionalStringField));
Assert.IsFalse(message.HasField(optionalBytesField));
Assert.IsFalse(message.HasField(optionalNestedEnumField));
// Set to default value is seen as not present
message = TestAllTypes.CreateBuilder()
.SetOptionalInt32(0)
.SetOptionalString("")
.SetOptionalBytes(ByteString.Empty)
.SetOptionalNestedEnum(TestAllTypes.Types.NestedEnum.FOO)
.Build();
Assert.IsFalse(message.HasField(optionalInt32Field));
Assert.IsFalse(message.HasField(optionalStringField));
Assert.IsFalse(message.HasField(optionalBytesField));
Assert.IsFalse(message.HasField(optionalNestedEnumField));
Assert.AreEqual(0, message.AllFields.Count);
// Set t0 non-defalut value is seen as present
message = TestAllTypes.CreateBuilder()
.SetOptionalInt32(1)
.SetOptionalString("x")
.SetOptionalBytes(ByteString.CopyFromUtf8("y"))
.SetOptionalNestedEnum(TestAllTypes.Types.NestedEnum.BAR)
.Build();
Assert.IsTrue(message.HasField(optionalInt32Field));
Assert.IsTrue(message.HasField(optionalStringField));
Assert.IsTrue(message.HasField(optionalBytesField));
Assert.IsTrue(message.HasField(optionalNestedEnumField));
Assert.AreEqual(4, message.AllFields.Count);
}