[Ironpython-users] clrtype.py duplicate type name within an assembly

[Jeff Hardy]

On Tue, Oct 30, 2012 at 8:13 PM, Jared Whitby <jwhitby at gmail.com> wrote:
> Hey guys,
>
> I've been trying to use IronPython as a scripting solution in a project I am
> working on. I am using clrtype.py from the clrtype sample to expose
> attributes on methods into c# so I can use reflection to register them with
> my application. The first time the script runs, everything works fine. But I
> want the users to be able to change the script while the application is
> running so I need to load and run the script again. When I try to load and
> run the script a second time I get a ArgumentException “Duplicate type name
> within an assembly”.
>
> ...
>
> Any ideas how to get around this? Am I doing something wrong that you can
> see?

It's a limitation of how IronPython generates code (and by extension,
clrtype.py). When it runs, it creates a dynamic assembly and creates
types in it, but it only does this once per process. Your use case is
interesting, and one that I don't think was ever considered - it was
assumed that the scripts (using clrtypes) would not be reloaded. One
potential issue is that I believe dynamic assemblies cannot be garbage
collected, although this may have changed in newer version of the CLR
(I can't keep track anymore!).

Would it be possible to not use reflection? Or does your system
require it for other reasons? You could potentially use the DLR APIs
to query the objects and then register them, which would avoid the use
of clrtypes at all.

- Jeff