Actually current version does support comments. It may be enabled with --include_source_info.
Comments are available in descriptor.Location[n].leading_comments and trailing_comments :
https://code.google.com/p/protobuf/source/browse/trunk/src/google/protobuf/descriptor.proto
I've added the corresponding properties to protobuf-net Location class:
private string _leading_comments = "";
[global::ProtoBuf.ProtoMember(3, IsRequired = false, Name = @"leading_comments", DataFormat = global::ProtoBuf.DataFormat.Default)]
[global::System.ComponentModel.DefaultValue("")]
public string leading_comments
{
get { return _leading_comments; }
set { _leading_comments = value; }
}
private string _trailing_comments = "";
[global::ProtoBuf.ProtoMember(4, IsRequired = false, Name = @"trailing_comments", DataFormat = global::ProtoBuf.DataFormat.Default)]
[global::System.ComponentModel.DefaultValue("")]
public string trailing_comments
{
get { return _trailing_comments; }
set { _trailing_comments = value; }
}
And added --include_source_info to protoc call (ProtoBuf.CodeGenerator.InputFileLoader)
And locations with comments were added to xml generated:
<?xml version="1.0" encoding="utf-16"?>
<FileDescriptorSet xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<file>
<FileDescriptorProto>
<name>Test.proto</name>
<dependency />
<message_type>
<DescriptorProto>
<name>Test2</name>
<field>
<FieldDescriptorProto>
<name>IntValue</name>
<number>1</number>
<type>TYPE_INT32</type>
</FieldDescriptorProto>
</field>
<extension />
<nested_type />
<enum_type />
<extension_range />
</DescriptorProto>
</message_type>
<enum_type />
<service />
<extension />
<source_code_info>
<location>
...
<Location>
<path>
<int>4</int>
<int>0</int>
<int>2</int>
<int>0</int>
</path>
<span>
<int>1</int>
<int>0</int>
<int>28</int>
</span>
<trailing_comments> some comment
</trailing_comments>
</Location>
...
</location>
</source_code_info>
</FileDescriptorProto>
</file>
</FileDescriptorSet>
source .proto:
message Test2{
optional int32 IntValue = 1;// some comment
}
But I'm not strong in xslt to update ProtoGen/csharp.xslt to include comments into CS file generated