Deserialization fail after switching PrefixStyle to Fixed32 - protocol-buffers

Question

I have a test suite for a communication library I'm developing using protobuf-net that is running okay. All tests pass. But if I change the PrefixStyle from Base128 to Fixed32, the deserialization fail.
The exception I receive from the TryDeserializeWithLengthPrefix function is:
System.ArgumentNullException was caught
Message="Value cannot be null.\r\nParameter name: type"
Source="protobuf-net"
ParamName="type"
Everything just works if I simple keep the PrefixStyle.Base128 when serializing and deserializing the message.
Does anyone know what may be happening?

Answer 1

Hohum, yup looks like a bug (now logged); repeatable example below. I'll see if I can fix it on the train (shortly). Sorry 'bout that:
using System;
using System.IO;
using ProtoBuf;
[ProtoContract]
public class Strange // test entity
{
[ProtoMember(1)]
public string Foo { get; set; } // test prop
[ProtoMember(2)]
public int Bar { get; set; } // test prop
static void Main() {
var original = new Strange { Foo = "abc", Bar = 123 };
// serialize and deserialize with base-128
using (MemoryStream ms = new MemoryStream()) {
Serializer.SerializeWithLengthPrefix(ms, original, PrefixStyle.Base128,1);
ms.Position = 0;
object obj;
Serializer.NonGeneric.TryDeserializeWithLengthPrefix(ms,
PrefixStyle.Base128, i => typeof(Strange),out obj);
var clone = (Strange)obj;
Console.WriteLine("Foo via Base128: " + clone.Foo); // works fine
Console.WriteLine("Bar via Base128: " + clone.Bar);
}
// serialize and deserialize with fixed-32
using (MemoryStream ms = new MemoryStream())
{
Serializer.SerializeWithLengthPrefix(ms, original, PrefixStyle.Fixed32,1);
ms.Position = 0;
object obj;
// BOOM here; oh how embarrassing
Serializer.NonGeneric.TryDeserializeWithLengthPrefix(ms,
PrefixStyle.Fixed32, i => typeof(Strange), out obj);
var clone = (Strange)obj;
Console.WriteLine("Foo via Fixed32: " + clone.Foo);
Console.WriteLine("Bar via Fixed32: " + clone.Bar);
}
}
}