runtimes in a multi threaded environment

[lysander12]

Hi,
We are using IronPython every day and we can solve every job with it.
However we would like to use unlimited number of IronPython runtimes in an application now and preload some runtimes on starting to be faster later.

I made a little demo for the bug we have found.
The traceback import is the most important part of the code.
Maybe the traceback module is made for CPython where I cannot image such a scenario but in IronPython it is possible to use multiple runtimes in an application.

The demo can result various misterious crashes.
The goal would be that it could run on a multi core PC.
Sometimes a Thread.Sleep(400) between the thread start methods helps sometimes does not.
Sometimes the bug appears only after a PC restart.

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        Thread t1 = new Thread(MakeRuntime);
        Thread t2 = new Thread(MakeRuntime);
        t1.Start();
        t2.Start();

    }
    void MakeRuntime() {
        try
        {
            Dictionary<string, object> options = new Dictionary<string, object>();
            options.Add("Debug", true);
            ScriptRuntime runtime = Python.CreateRuntime(options);
            ScriptEngine engine = runtime.GetEngine("py");

            List<string> paths = new List<string>();
            paths.Add(@"C:\Program Files (x86)\IronPython 2.7\Lib\");
            engine.SetSearchPaths(paths);
            ScriptScope scope = engine.CreateScope();
            engine.Execute("import sys;import traceback;", scope);
        }
        catch (Exception ex) {
            MessageBox.Show(ex.ToString());
        }
    }
}

Best Regards
David Fulop

[paweljasinski]

here are a couple of stack traces generated from slightly modified (no gui) code.

[jdhardy]

Weakref seems like the common thread (ahem) in this case. There must be a synchronization issue in the weakref code, and I think there might be a couple of other open issues that have a similar problem.

[jdhardy]

See also http://stackoverflow.com/q/28734990/81117.

[jdhardy]

This is probably related to #1187.