NHibernate 1.2 in a .NET 4.0 solution

Question

Hello,
I have some projects based on NHibernate 1.2 and I'd like to add them to a .NET 4.0 solution, but I get an AmbiguousMatchException.
No matter if these projects are targeted to 2.0 or 4.0 framework.
It works if I add them to a .NET 3.5 solution.

Does anyone have experience with that?

Here is the exception:

[AmbiguousMatchException: Ambiguous match found.]
   System.RuntimeType.GetMethodImpl(String name, BindingFlags bindingAttr, Binder binder, CallingConventions callConv, Type[] types, ParameterModifier[] modifiers) +9607924
   System.Type.GetMethod(String name) +29
   Castle.DynamicProxy.Builder.CodeBuilder.SimpleAST.LockBlockExpression.Emit(IEasyMember member, ILGenerator gen) +192
   Castle.DynamicProxy.Builder.CodeBuilder.SimpleAST.ExpressionStatement.Emit(IEasyMember member, ILGenerator gen) +52
   Castle.DynamicProxy.Builder.CodeBuilder.AbstractCodeBuilder.Generate(IEasyMember member, ILGenerator il) +370
   Castle.DynamicProxy.Builder.CodeBuilder.EasyMethod.Generate() +71
   Castle.DynamicProxy.Builder.CodeBuilder.AbstractEasyType.EnsureBuildersAreInAValidState() +706
   Castle.DynamicProxy.Builder.CodeBuilder.AbstractEasyType.BuildType() +90
   Castle.DynamicProxy.Builder.CodeGenerators.BaseCodeGenerator.CreateType() +55
   Castle.DynamicProxy.Builder.CodeGenerators.ClassProxyGenerator.GenerateCode(Type baseClass, Type[] interfaces) +573
   Castle.DynamicProxy.Builder.DefaultProxyBuilder.CreateClassProxy(Type theClass, Type[] interfaces) +87
   Castle.DynamicProxy.ProxyGenerator.CreateClassProxy(Type baseClass, Type[] interfaces, IInterceptor interceptor, Boolean checkAbstract, Object[] argumentsForConstructor) +116
   NHibernate.Proxy.CastleProxyFactory.GetProxy(Object id, ISessionImplementor session) +136

[HibernateException: Creating a proxy instance failed]
   NHibernate.Proxy.CastleProxyFactory.GetProxy(Object id, ISessionImplementor session) +270
   NHibernate.Persister.Entity.AbstractEntityPersister.CreateProxy(Object id, ISessionImplementor session) +17
   NHibernate.Impl.SessionImpl.DoLoadByClass(Type clazz, Object id, Boolean checkDeleted, Boolean allowProxyCreation) +354
   NHibernate.Impl.SessionImpl.InternalLoad(Type clazz, Object id, Boolean eager, Boolean isNullable) +52
   NHibernate.Type.EntityType.ResolveIdentifier(Object id, ISessionImplementor session) +37
   NHibernate.Type.EntityType.ResolveIdentifier(Object id, ISessionImplementor session, Object owner) +55
   NHibernate.Impl.SessionImpl.InitializeEntity(Object obj) +187
   NHibernate.Loader.Loader.InitializeEntitiesAndCollections(IList hydratedObjects, Object resultSetId, ISessionImplementor session) +229
   NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies) +702
   NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies) +62
   NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters) +51
   NHibernate.Loader.Loader.ListIgnoreQueryCache(ISessionImplementor session, QueryParameters queryParameters) +18
   NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet querySpaces, IType[] resultTypes) +81
   NHibernate.Loader.Criteria.CriteriaLoader.List(ISessionImplementor session) +36
   NHibernate.Impl.SessionImpl.Find(CriteriaImpl criteria, IList results) +315
   NHibernate.Impl.SessionImpl.Find(CriteriaImpl criteria) +66
   NHibernate.Impl.CriteriaImpl.List() +54  
   [my code calling Criteria.List()]

Answer 1

NHibernate 1.x is completely unsupported at this point. You should upgrade at least to 2.1.2.

In any case, it's clear from the error message that the problem is not in NHibernate itself, but in Castle DynamicProxy.

Answer 2

Following Rup's comment, I resolved changing the sources of Castle DynamicProxy 1.1.5 and recompiling.
The problem is invoking with reflection the method System.Threading.Monitor.Enter without specifying arguments (that's because in .NET 2.0 there is only 1 signature), but since .NET 4.0 that method has 2 overloads.

I've modified the class Castle.DynamicProxy.Builder.CodeBuilder.SimpleAST.LockBlockExpression, changing the row

gen.Emit(OpCodes.Call, typeof(Monitor).GetMethod("Enter"));

with the row

gen.Emit(OpCodes.Call, typeof(Monitor).GetMethod("Enter", new Type[] { typeof(object) }));

I've got the sources of NHibernate 1.2 from SourceForge while I disassembled the code of Castle DynamicProxy 1.1.5 with Reflector.