[Ironruby-core] Problem with Marshal.load in Silverlight

Tomas Matousek Tomas.Matousek at microsoft.com
Mon Jul 26 21:40:07 EDT 2010

Filed a bug: http://ironruby.codeplex.com/workitem/4946

Jimmy has something almost ready for running tests on Silverlight.


From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Charles Strahan
Sent: Monday, July 26, 2010 6:26 PM
To: ironruby-core at rubyforge.org
Subject: Re: [Ironruby-core] Problem with Marshal.load in Silverlight

Alright, I know I'm not supposed to send in patch's for the runtime, but this is a bug in the Silverlight build.  Classes implemented in Ruby cannot be created using RubyUtils.CreateObject, as I mentioned in my previous email.  As a result, Marshal.load will fail when trying to deserialize classes implemented in Ruby, because the _underlyingSystemType will be RubyObject, which implements ISerializable. In the debugger, if I force the aforementioned CreateObject method to call the CreateObject(RubyClass/*!*/ theClass) overload, it works just fine.

We probably need to change this:
if (typeof(ISerializable).IsAssignableFrom(baseType)) {

to this:
if (typeof(ISerializable).IsAssignableFrom(baseType) && !(baseType is RubyObject)) {

Should I make this change to my fork?  Or would one of you core dev's make the appropriate change for us (Tomas :p)?


Would there be any interest in being able to mspec the Silverlight build?  I would bet that would make catching these little bugs much easier.  I could throw something together if it would help - something like a command line app called slmspec.



On Sun, Jul 25, 2010 at 4:25 AM, Charles Strahan <charles.c.strahan at gmail.com<mailto:charles.c.strahan at gmail.com>> wrote:
I've run into a problem when using Marshal.load in Silverlight - the following exception is thrown:

NotSupportedException: Class IronRuby.Builtins.RubyObject does not have a valid deserializing constructor

I tracked the code down to RubyUtils.CreateObject(RubyClass/*!*/ theclass, IEnumerable<KeyValuePair<string, object>>/*!*/ attributes).  I see that CreateObject will always throw in Silverlight when the type is assignable from ISerializable:

        public static object/*!*/ CreateObject(RubyClass/*!*/ theclass, IEnumerable<KeyValuePair<string, object>>/*!*/ attributes) {
            Assert.NotNull(theclass, attributes);

            Type baseType = theclass.GetUnderlyingSystemType();
            object obj;
            if (typeof(ISerializable).IsAssignableFrom(baseType)) {
#if !SILVERLIGHT // serialization
                BindingFlags bindingFlags = BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance;
                ConstructorInfo ci = baseType.GetConstructor(bindingFlags, null, _serializableTypeSignature, null);
                if (ci == null) {
                string message = String.Format("Class {0} does not have a valid deserializing constructor", baseType.FullName);
                    throw new NotSupportedException(message);
#if !SILVERLIGHT // serialization
                SerializationInfo info = new SerializationInfo(baseType, new FormatterConverter());
                info.AddValue(SerializationInfoClassKey, theclass);
                foreach (var pair in attributes) {
                    info.AddValue(pair.Key, pair.Value);
                obj = ci.Invoke(new object[2] { info, new StreamingContext(StreamingContextStates.Other, theclass) });
            } else {
                obj = CreateObject(theclass);
                foreach (var pair in attributes) {
                    theclass.Context.SetInstanceVariable(obj, pair.Key, pair.Value);
            return obj;

Is this a bug, perhaps? I'd love to step through the code and find for myself, but I can't seem to build IronRuby using the Silverlight3 and Silverlight4 build configurations (I get a ton of errors - any help getting it to build would rock!).


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