René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":".Net core 3.1 using netstandard polyfill causes error.","articleBody":"### Environment\r\n\r\n-   Pythonnet version: NuGet v 2.5.1  (pythonnet_netstandard_py37_linux)\r\n-   Python version: 3.7\r\n-   Operating System: Linux (ubuntu 18.04)\r\n\r\n### Details\r\n\r\n-   Trying to embed python in a c# core 3.1 console app.  Within python I wanted to attach a delegate to an event on a c# object.  The creation of the delegate type in DelegateManager.cs GetDispatcher calls TypeBuilder.CreateType.  In .net standard, this calls the polyfill.  Under core 3.1 a polyfill shouldn't be necessary.  However, this polyfill appears to be defined incorrectly.  It's defined as: \r\n```\r\npublic static Type CreateType(this TypeBuilder typeBuilder)\r\n{\r\n    return typeBuilder.GetTypeInfo().GetType();\r\n}\r\n```\r\nHowever, the actual method in 3.1 is this:\r\n```public Type CreateType() =\u003e (Type) this.CreateTypeInfo();```\r\n\r\nThe difference being that the extra GetType() results in us returning the equivalent of typeof(System.Reflection.Emit.TypeBuilder).  Which then fails to create with the arguments of a delegate.  \r\n\r\n-   What commands did you run to trigger this issue? If you can provide a\r\n    [Minimal, Complete, and Verifiable example](http://stackoverflow.com/help/mcve)\r\n    this will help us understand the issue.\r\n\r\nI don't have one offhand, but I will work on a pull reqeust unless someone has some advise for how to avoid the issue.  For a pull request, my plan is to #if the polyfill for !NETCOREAPP3_1\r\n\r\n-   If there was a crash, please include the traceback here.\r\n\r\nNot quite as useful as what I have above, but here is the traceback:\r\n```\r\nUnhandled exception. System.MissingMethodException: Constructor on type 'System.Reflection.Emit.TypeBuilder' not found.\r\n   at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture)\r\n   at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)\r\n   at System.Activator.CreateInstance(Type type, Object[] args)\r\n   at Python.Runtime.DelegateManager.GetDelegate(Type dtype, IntPtr callable)\r\n   at Python.Runtime.EventObject.AddEventHandler(IntPtr target, IntPtr handler)\r\n   at Python.Runtime.EventBinding.nb_inplace_add(IntPtr ob, IntPtr arg)\r\n   at Python.Runtime.Runtime.PyRun_String(String code, IntPtr st, IntPtr globals, IntPtr locals)\r\n   at Python.Runtime.PyScope.Exec(String code, IntPtr _globals, IntPtr _locals)\r\n   at Python.Runtime.PyScope.Exec(String code, PyDict locals)\r\n   at Oreo.Middleware.Calibration.Program.Main(String[] args) in /home/user/dev/Oreo/Oreo/src/Oreo.Middleware.Calibration/Program.cs:line 24\r\n```\r\nNote that I'm trying to create a delegate, and it's having a hard time finding the appropriate constructor on System.Reflection.Emit.TypeBuilder.","author":{"url":"https://github.com/shadowbane1000","@type":"Person","name":"shadowbane1000"},"datePublished":"2020-09-16T20:50:25.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/1228/pythonnet/issues/1228"}