VS: crash or hang when accessing F# Text Editor options

[majocha]

Current main installed on 17.10 preview 2:

Repro steps

Open settings, go to Text Editor -> F# -> Advanced ( or any other F# page).

VS either hangs or crashes and restarts.

Attempting to debug this in experimental instance I get:

Managed Debugging Assistant 'FatalExecutionEngineError' : 'The runtime has encountered a fatal error. The address of the error was at 0x423bffe8, on thread 0x763c. The error code is 0x80131623. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack.'

[brianrourkeboll]

I've seen this as well.

[majocha]

Possibly it's some VS platform / WPF bug.
It happens around setting DataContext for the view, the options window just breaks:

[majocha]

Original version released with 17.10 preview i.e:
Visual F# Tools 17.10.0-beta.24127.3+b57dee7cec971021547a7b8a36a46d7271fea99e
works fine.

[vzarytovskii]

I bet it's translation.

[vzarytovskii]

Ok, maybe not

Microsoft.VisualStudio.Composition.CompositionFailedException: Expected 1 export(s) with contract name "Microsoft.VisualStudio.FSharp.Editor.SettingsStore+ISettingsStore" but found 0 after applying applicable constraints.
   at Microsoft.VisualStudio.Composition.ExportProvider.GetExports(ImportDefinition importDefinition)
   at Microsoft.VisualStudio.Composition.ExportProvider.GetExports[T,TMetadataView](String contractName, ImportCardinality cardinality)
   at Microsoft.VisualStudio.Composition.ExportProvider.GetExport[T,TMetadataView](String contractName)
   at Microsoft.VisualStudio.Composition.ExportProvider.GetExportedValue[T]()
   at Microsoft.VisualStudio.ComponentModelHost.ComponentModel.GetService[T]()
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at Microsoft.VisualStudio.FSharp.Editor.OptionsUIHelpers.AbstractOptionPage`1.OnActivate(CancelEventArgs _arg1) in C:\Users\vlza\code\fsharp\vsintegration\src\FSharp.Editor\Options\UIHelpers.fs:line 37
   at Microsoft.VisualStudio.Shell.DialogPage.DialogSubclass.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at Microsoft.Internal.VisualStudio.Shell.Interop.IVsToolsOptionsPrivate2.ShowToolsOptions(Guid selectedPageId)
   at Microsoft.VisualStudio.Services.UnifiedSettings.VsCommands.ToolsOptionsCommand.<>c__DisplayClass6_0.<<Execute>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Shell.VsTaskLibraryHelper.<>c.<<FileAndForget>b__35_0>d.MoveNext()

[majocha]

@vzarytovskii this call stack looks helpful! I got it to work again at least in debug. I'll post what I got soon.

[majocha]

Nah, now I just can't repro this at all, on main without any changes. It just comes and goes. At least not in the experimental VS instance.

[vzarytovskii]

Nah, now I just can't repro this at all, on main without any changes. It just comes and goes.

My "fix" in PR seems to work for me 5/5 times (when VSIX is deployed). It looks like something is wrong with MEF, I have 2 working theories:

1. There's a race condition between when we registering it in the EditorOptions type (via properly attribute).
2. Something changed with registering it + visibility.

It seems I can't figure out for sure what's happening.

[majocha]

@vzarytovskii I can't repro in debug at all now, but I'll test your fix on my VS installation in a moment.

[vzarytovskii]

@vzarytovskii I can't repro in debug at all now, but I'll test your fix on my VS installation in a moment.

I couldn't reproduce in debug either

[majocha]

Works!