Protobuf-net Error: Type is not expected, and no contract can be inferred: BlockHeader

Question

Trying to get de-serialization of an openstreetmap pbf file working properly by following information from this thread as well as other sources:

Protobuf-net Deserialize Open Street Maps

I'm currently using the protobug dll from r480. I used protogen to create the csharp class files from the osm proto's, but when I hit this point in the code where I'm trying to read in from the stream:

BlockHeader header;
using (var tmp = new LimitedStream(file, length))
{
    header = Serializer.Deserialize<BlockHeader>(tmp); // exception occurs here
}

It throws the following exception:

InnerException: System.InvalidOperationException
Message=Type is not expected, and no contract can be inferred: BlockHeader
Source=protobuf-net
StackTrace:
  at ProtoBuf.Meta.TypeModel.ThrowUnexpectedType(Type type) in C:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 1115
  at ProtoBuf.Meta.TypeModel.TryDeserializeAuxiliaryType(ProtoReader reader, DataFormat format, Int32 tag, Type type, Object& value, Boolean skipOtherFields, Boolean asListItem, Boolean autoCreate, Boolean insideList) in C:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 848
  at ProtoBuf.Meta.TypeModel.DeserializeCore(ProtoReader reader, Type type, Object value, Boolean noAutoCreate) in C:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 582
  at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type, SerializationContext context) in C:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 506
  at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type) in C:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 488
  at ProtoBuf.Serializer.Deserialize[T](Stream source) in C:\Dev\protobuf-net\protobuf-net\Serializer.cs:line 69
  at OsmParserDemo.MainWindow.OsmParse() in C:\Users\crussell\Documents\Visual Studio 2010\Projects\OsmParseMadness\OsmParserDemo\MainWindow.xaml.cs:line 57
  at OsmParserDemo.MainWindow..ctor() in C:\Users\crussell\Documents\Visual Studio 2010\Projects\OsmParseMadness\OsmParserDemo\MainWindow.xaml.cs:line 28

So in comparing the code structure to that of the protobuf-net example I get the impression that I may be missing something in regards to identifying each member. Is this correct, or am I way out in space on this one? Any help or hints are greatly appreciated!

Edit: Here's a snippet of BlockHeader from the generated FileFormat.cs class:

BlockHeader

Answer 1

With your addition of the code file, all becomes clear. The library you are using, based on the stack-trace, is protobuf-net; but that .cs file has nothing to do with protobuf-net. Well, very little.

You see, there are (at least) 2 c#/.net protobuf implementations, and I think you're mixing them up:

• protobuf-csharp-port is by Jon Skeet, and is a direct port of the Java version, meaning: it follows the same design principles and API. Tempting if you work in both C# and Java.
• protobuf-net is by me, and is a from-first-principles implementation that aims to be idiomatic .NET, meaning: it can work code-first, against your existing types (basically, like XmlSerializer, DataContractSerializer, etc can), but also supports usage from .proto if you want

Confusingly, both of them feature a code-generation tool called "protogen". AFAIK, this naming coincidence was just natural convergence/coincidence, rather than planning (good or malign).

A c# file generated from protobuf-csharp-port's protogen will work with the protobuf-csharp-port library

A c# file generated from protobuf-net's protogen will work with the protobuf-net library

Here's the protobuf-net generated version, including BlockHeader:

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

// Generated from: Foo.proto
namespace ConsoleApplication9
{
  [global::System.Serializable, global::ProtoBuf.ProtoContract(Name=@"Blob")]
  public partial class Blob : global::ProtoBuf.IExtensible
  {
    public Blob() {}


    private byte[] _raw = null;
    [global::ProtoBuf.ProtoMember(1, IsRequired = false, Name=@"raw", DataFormat = global::ProtoBuf.DataFormat.Default)]
    [global::System.ComponentModel.DefaultValue(null)]
    public byte[] raw
    {
      get { return _raw; }
      set { _raw = value; }
    }

    private int _raw_size = default(int);
    [global::ProtoBuf.ProtoMember(2, IsRequired = false, Name=@"raw_size", DataFormat = global::ProtoBuf.DataFormat.TwosComplement)]
    [global::System.ComponentModel.DefaultValue(default(int))]
    public int raw_size
    {
      get { return _raw_size; }
      set { _raw_size = value; }
    }

    private byte[] _zlib_data = null;
    [global::ProtoBuf.ProtoMember(3, IsRequired = false, Name=@"zlib_data", DataFormat = global::ProtoBuf.DataFormat.Default)]
    [global::System.ComponentModel.DefaultValue(null)]
    public byte[] zlib_data
    {
      get { return _zlib_data; }
      set { _zlib_data = value; }
    }

    private byte[] _lzma_data = null;
    [global::ProtoBuf.ProtoMember(4, IsRequired = false, Name=@"lzma_data", DataFormat = global::ProtoBuf.DataFormat.Default)]
    [global::System.ComponentModel.DefaultValue(null)]
    public byte[] lzma_data
    {
      get { return _lzma_data; }
      set { _lzma_data = value; }
    }

    private byte[] _bzip2_data = null;
    [global::ProtoBuf.ProtoMember(5, IsRequired = false, Name=@"bzip2_data", DataFormat = global::ProtoBuf.DataFormat.Default)]
    [global::System.ComponentModel.DefaultValue(null)]
    public byte[] bzip2_data
    {
      get { return _bzip2_data; }
      set { _bzip2_data = value; }
    }
    private global::ProtoBuf.IExtension extensionObject;
    global::ProtoBuf.IExtension global::ProtoBuf.IExtensible.GetExtensionObject(bool createIfMissing)
      { return global::ProtoBuf.Extensible.GetExtensionObject(ref extensionObject, createIfMissing); }
  }

  [global::System.Serializable, global::ProtoBuf.ProtoContract(Name=@"BlockHeader")]
  public partial class BlockHeader : global::ProtoBuf.IExtensible
  {
    public BlockHeader() {}

    private string _type;
    [global::ProtoBuf.ProtoMember(1, IsRequired = true, Name=@"type", DataFormat = global::ProtoBuf.DataFormat.Default)]
    public string type
    {
      get { return _type; }
      set { _type = value; }
    }

    private byte[] _indexdata = null;
    [global::ProtoBuf.ProtoMember(2, IsRequired = false, Name=@"indexdata", DataFormat = global::ProtoBuf.DataFormat.Default)]
    [global::System.ComponentModel.DefaultValue(null)]
    public byte[] indexdata
    {
      get { return _indexdata; }
      set { _indexdata = value; }
    }
    private int _datasize;
    [global::ProtoBuf.ProtoMember(3, IsRequired = true, Name=@"datasize", DataFormat = global::ProtoBuf.DataFormat.TwosComplement)]
    public int datasize
    {
      get { return _datasize; }
      set { _datasize = value; }
    }
    private global::ProtoBuf.IExtension extensionObject;
    global::ProtoBuf.IExtension global::ProtoBuf.IExtensible.GetExtensionObject(bool createIfMissing)
      { return global::ProtoBuf.Extensible.GetExtensionObject(ref extensionObject, createIfMissing); }
  }

}

Conclusion:

Either use the protobuf-net protogen, or use the protobuf-csharp-port library. No mix and match.