IronLanguages / IronLanguages/ironpython3

IronPython3 PlatformNotSupportedException in .NET WASM

Open
#1,952 2 comments 1 reaction 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
C#
Stars
2.8k
Forks
316
Avg merge
1d 9h
Merged PRs (30d)
1

Description

Maybe this is a regression based on the PR here, seemingly indicating that it was the fix to make IronPython3 work with Blazor: https://github.com/IronLanguages/dlr/pull/256
Though this issue remained open on IronPython2 (but again indicated the scenario should work in IronPython3): https://github.com/IronLanguages/ironpython2/issues/769

I'm in an Uno Platform WASM context (should be the same as Blazor). And when I tried to call CreateEngine I got this exception (which looks like it's trying to find the console, though that was what the above PR was supposed to fix?):

System.Reflection.TargetInvocationException: Failed to load language 'IronPython 3.4.2': Operation is not supported on this platform.
 ---> System.PlatformNotSupportedException: Operation is not supported on this platform.
   at System.ConsolePal.get_InputEncoding()
   at System.Console.get_InputEncoding()
   at Microsoft.Scripting.Runtime.SharedIO.InitializeInput()
   at Microsoft.Scripting.Runtime.SharedIO.get_InputEncoding()
   at IronPython.Modules.PythonIOModule.CreateConsole(PythonContext context, SharedIO io, ConsoleStreamType type, String name, StreamBox& sio)
   at IronPython.Runtime.PythonContext.SetStandardIO()
   at IronPython.Runtime.PythonContext.InitializeSystemState()
   at IronPython.Runtime.PythonContext..ctor(ScriptDomainManager manager, IDictionary`2 options)
   at System.Object.InvokeStub_PythonContext..ctor(Object , Span`1 )
   at System.Reflection.MethodBaseInvoker.InvokeWithFewArgs(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   --- End of inner exception stack trace ---
   at Microsoft.Scripting.Runtime.LanguageConfiguration.LoadLanguageContext(ScriptDomainManager domainManager, Boolean& alreadyLoaded)
   at Microsoft.Scripting.Runtime.DlrConfiguration.LoadLanguageContext(ScriptDomainManager manager, LanguageConfiguration config)
   at Microsoft.Scripting.Runtime.DlrConfiguration.TryLoadLanguage(ScriptDomainManager manager, AssemblyQualifiedTypeName& providerName, LanguageContext& language)
   at Microsoft.Scripting.Runtime.ScriptDomainManager.GetLanguageByTypeName(String providerAssemblyQualifiedTypeName)
   at Microsoft.Scripting.Hosting.ScriptRuntime.GetEngineByTypeName(String assemblyQualifiedTypeName)
   at IronPython.Hosting.Python.GetEngine(ScriptRuntime runtime)
   at IronPython.Hosting.Python.CreateEngine()

Perhaps some similar try/catch fallback helper logic to https://github.com/IronLanguages/dlr/pull/256 needs to be implemented here?

https://github.com/IronLanguages/ironpython3/blob/71a8f5ca374ae6ebe7d746d674090e51b5160ab3/src/core/IronPython/Runtime/PythonContext.cs#L1862-L1868

I don't need input in my scenario, and plan to redirect the output already. Though not sure if there'd be other blockers beyond this.

Already been poking at this too late today, but will see if I can build the repo and investigate, VS doesn't seem to let me step-in to the function in the WASM debug context for some reason.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the CreateEngine failure in the reported Uno Platform WASM context and read PythonContext.cs at lines 1862-1868, then compare the fallback logic in DLR PR 256. Reproduce the PlatformNotSupportedException and determine whether engine creation can complete without console input; done means the reported WASM scenario no longer fails at this point.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp, python, wasm
Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
38/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.