[Ironruby-core] Returning a Clr type in IronRuby

Tomas Matousek Tomas.Matousek at microsoft.com
Tue Mar 3 12:55:12 EST 2009


The problem is that CLR/Mono assembly loader loads the assembly twice into 2 different contexts: "LoadNeither" and "Default".
Therefore there are actually 2 different types "BuildMetaData" in system.

require 'Horn.Core.DSL.Domain' uses Assembly.LoadFrom to load the assembly, which loads it to one context.
A static assembly reference (in C#) is loaded via Assembly.Load, which loads to a different context.

You can use Kernel#load_assembly or require '<full assembly name>' to invoke Assembly.Load.

Tomas

From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Paul Cowan
Sent: Tuesday, March 03, 2009 6:53 AM
To: ironruby-core at rubyforge.org
Subject: [Ironruby-core] Returning a Clr type in IronRuby

Hi,
I am trying to return a CLR object from Iron Ruby.

I have the following CLR type defined in C#

public class BuildMetaData
{
    public string Description { get; set; }
}

I have the following IronRuby file:
$:.unshift(File.dirname(__FILE__) + '/../bin/Debug')
require 'mscorlib'
require 'Horn.Core.DSL.Domain'
class MetaDataFactory
    def return_meta_data()
        meta = Horn::Core::DSL::Domain::BuildMetaData.new
        meta.Description = "A description of sorts"
        meta
    end
end

I have the following test that is failing:
[Fact]
public void Then_a_build_metadata_object_is_returned()
{
   var engine = Ruby.CreateEngine();
   engine.Runtime.LoadAssembly(typeof (BuildMetaData).Assembly);
   engine.ExecuteFile(buildFile);
   var klass = engine.Runtime.Globals.GetVariable("MetaDataFactory");
   var instance = (RubyObject)engine.Operations.CreateInstance(klass);
   var metaData = (BuildMetaData)engine.Operations.InvokeMember(instance, "return_meta_data");
   Assert.Equal(metaData.Description, "A description of sorts");
}

It fails when trying to cast the object returned from IronRuby with the following error.
System.InvalidCastException : [A]Horn.Core.DSL.Domain.BuildMetaData cannot be cast to [B]Horn.Core.DSL.Domain.BuildMetaData. Type A originates from 'Horn.Core.DSL.Domain, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' in the context 'LoadNeither' at location 'C:\Projects\horn\branches\rubydsl\src\Horn.Dsl.Specificatioin\bin\Debug\Horn.Core.DSL.Domain.dll'. Type B originates from 'Horn.Core.DSL.Domain, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' in the context 'Default' at location 'C:\Users\paul.cowan\AppData\Local\Temp\gjpo5svj.0zd\Horn.Dsl.Specificatioin\assembly\dl3\6d8ae49c\7acadf2b_c798c901\Horn.Core.DSL.Domain.DLL'.

The only way I can access the members of the BuildMetaData is using reflection.

If you look at the error message, both types are created in different locations.

Is this possible in IronRuby yet?

Cheers

Paul
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