[NMock2-Dev] Exception when mocking an interface with generic methods

[Michael A. <at...@am...>]

We recently upgraded to NMock2 RC2 but found a regression when mocking an
interface with a generic method. Attempting to generate a mock for an
interface like:

    public interface IWithGenericMethods
    {
        T ReadVariable<T>(string name);
        void SetVariable<T>(string name, T val);
    }

throws the following exception:

failed: System.TypeLoadException : Signature of the body and declaration in
a method implementation do not match.  Type: 'MockObjectType1'.  Assembly:
'MockObjects, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'.
    at System.Reflection.Emit.TypeBuilder._TermCreateClass(Int32 handle,
Module module)
    at System.Reflection.Emit.TypeBuilder.CreateTypeNoLock()
    at System.Reflection.Emit.TypeBuilder.CreateType()

C:\Software\RIA\ThirdPartyLibraries\NMock2\nmock2\src\NMock2\Monitoring\MockObjectFactory.cs(153,0):
at NMock2.Monitoring.MockObjectFactory.CreateType(String typeName, Type
mockedType)
    C:\nmock2\src\NMock2\Monitoring\MockObjectFactory.cs(137,0): at
NMock2.Monitoring.MockObjectFactory.GetMockedType(TypeId id1, Type
mockedType)
    C:\nmock2\src\NMock2\Monitoring\MockObjectFactory.cs(120,0): at
NMock2.Monitoring.MockObjectFactory.CreateMockObject(Mockery mockery, Type
mockedType, String name)
    C:\nmock2\src\NMock2\Mockery.cs(53,0): at NMock2.Mockery.NewMock(Type
mockedType, String name)

The exception occurs because
NMock2.Monitoring.MockObjectFactory.PrepareMethodGenerator() does not define
the generic parameters on the MethodBuilder for needed for generic methods.
I was able to patch a local copy to correct this problem using an example
from the Spring.NET project. The relevant code is on line 195-219 of
http://springnet.cvs.sourceforge.net/springnet/Spring.Net/src/Spring/Spring.Core/Proxy/AbstractProxyMethodBuilder.cs?revision=1.6&view=markup
(The ReflectionUtils.GetGenericParameterNames() method referenced by that
code simply returns an array of strings built from the Type.Name array
passed in)

Hopefully the NMock2 source can be patched to correct this problem before
the next release.

Thanks for all of the recent improvements,
    Mike Attili
    Amaxo, Inc.