After installing extension in VS, Blend hits NullReferenceException when loading solution

[angusgraham]

• GitHub Extension for Visual Studio version: 2.5.1.2234
• Visual Studio version: 15.6.6
  Note that GitHub appears in the list of extensions for VS, but not for Blend.

When loading a WPF solution Blend I hit an exception.
Here are the relevant parts of the Blend ActivityLog.xaml:

194 2018/04/20 17:14:08.602 Error Microsoft.VisualStudio.CommonIDE.ExtensibilityHosting.VsShellComponentModelHost Still unable to load MEF component DLL: Could not load file or assembly 'Microsoft.TeamFoundation.Git.Provider, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\PROFESSIONAL\COMMON7\IDE\EXTENSIONS\GITHUB\GITHUB\GitHub.TeamFoundation.14.dll 379 2018/04/20 17:14:08.702 Information Extension Manager Successfully loaded extension... C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\PROFESSIONAL\COMMON7\IDE\EXTENSIONS\GITHUB\GITHUB\ 380 2018/04/20 17:14:08.702 Information Extension Manager Extension is enabled... C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\PROFESSIONAL\COMMON7\IDE\EXTENSIONS\GITHUB\GITHUB\ 514 2018/04/20 17:14:13.841 Error Editor or Editor Extension System.NullReferenceException: Object reference not set to an instance of an object. at GitHub.InlineReviews.InlineCommentMarginProvider.IsMarginDisabled(IWpfTextViewHost textViewHost) in C:\projects\visualstudio\src\GitHub.InlineReviews\InlineCommentMarginProvider.cs:line 98 at GitHub.InlineReviews.InlineCommentMarginProvider.CreateMargin(IWpfTextViewHost wpfTextViewHost, IWpfTextViewMargin parent) in C:\projects\visualstudio\src\GitHub.InlineReviews\InlineCommentMarginProvider.cs:line 70 at Microsoft.VisualStudio.Text.Utilities.ContainerMargin.<AddMargins>b__25_1(IWpfTextViewMarginProvider mp) at Microsoft.VisualStudio.Text.Utilities.GuardedOperations.InstantiateExtension[TExtension,TMetadata,TExtensionInstance](Object errorSource, Lazy`2 provider, Func`2 getter) --- End of stack trace from previous location where exception was thrown --- at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)

[meaghanlewis]

Hi @angusgraham thanks for reporting this issue. I was able to reproduce it while trying to use the GitHub extension with Blend. It looks like the same issue was reported in the past: #951.

Our team put out a fix it, so this looks like a regression. What do you think @jcansdale?

[xperiandri]

Exception in Team Explorer on Connect page

Microsoft.VisualStudio.Composition.CompositionFailedException: An exception was thrown while initializing part "GitHub.VisualStudio.Base.TeamExplorerServiceHolder". ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at GitHub.VisualStudio.Base.TeamExplorerServiceHolder.UpdateActiveRepo() in C:\projects\visualstudio\src\GitHub.TeamFoundation.14\Base\TeamExplorerServiceHolder.cs:line 138
   at GitHub.VisualStudio.Base.TeamExplorerServiceHolder..ctor(IVSGitExt gitService) in C:\projects\visualstudio\src\GitHub.TeamFoundation.14\Base\TeamExplorerServiceHolder.cs:line 37
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
   --- End of inner exception stack trace ---
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState)
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose()
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.<>c__DisplayClass15_0.<GetExportedValueHelper>b__0()
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportElement(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import, RuntimeExport export, Func`3 lazyFactory)
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportSite(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import)
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.<CreateValue>b__10_0(RuntimeImport import)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState)
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose()
   at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass53_0.<CreateExport>b__0()
   at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass55_0.<CreateExportFactoryExport>b__1()
   at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass54_0.<CreateExportFactory>b__0()
   at Microsoft.VisualStudio.Composition.DelegateServices.<>c__DisplayClass2_0`1.<As>b__0()
   at System.ComponentModel.Composition.ExportFactory`1.CreateExport()
   at Microsoft.VisualStudio.Composition.NetFxAdapters.MefV1ExportProvider.ComposablePartDefinitionForExportFactory.CreatePart()
   at System.ComponentModel.Composition.ReflectionModel.ExportFactoryCreator.LifetimeContext.GetExportLifetimeContextFromExport[T](Export export)
   at System.ComponentModel.Composition.ReflectionModel.ExportFactoryCreator.<>c__DisplayClass6_0`2.<CreateStronglyTypedExportFactoryOfTM>b__0()
   at System.ComponentModel.Composition.ExportFactory`1.CreateExport()
   at Microsoft.TeamFoundation.Controls.WPF.TeamExplorer.Framework.TeamExplorerSectionHost.Create()

[jcansdale]

@angusgraham I'm surprised you're seeing this. The InlineCommentMarginProvider component should only be loaded when the process is called devenv (in Visual Studio).

17:14:13.841 Error Editor or Editor Extension System.NullReferenceException: Object reference not set to an instance of an object.
at GitHub.InlineReviews.InlineCommentMarginProvider.IsMarginDisabled(IWpfTextViewHost textViewHost)
in C:\projects\visualstudio\src\GitHub.InlineReviews\InlineCommentMarginProvider.cs:line 98 at 

I'll work with @meaghanlewis next week to fix it.

@xperiandri I noticed a similar exception to the one you reported when running VS 2017 in "Safe Mode". Blend has the equivalent of "Safe Mode" enabled all the time and only loads known Microsoft packages. Could you try this build (from #1649) and let me know if you notice any more issues?
https://ci.appveyor.com/api/buildjobs/six3ggdgltlr8jbr/artifacts/2.5.1.2369%2FGitHub.VisualStudio.vsix

[bberrevoets]

Same problem here, but when I am reverting back to version 2.2.0.10 of the GitHub extension, then everything is ok.

[xperiandri]

@jcansdale, same thing

Microsoft.VisualStudio.Composition.CompositionFailedException: An exception was thrown while initializing part "GitHub.VisualStudio.Base.TeamExplorerServiceHolder". ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at GitHub.VisualStudio.Base.TeamExplorerServiceHolder..ctor(IVSGitExt gitService) in C:\projects\visualstudio\src\GitHub.TeamFoundation.14\Base\TeamExplorerServiceHolder.cs:line 38
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
   --- End of inner exception stack trace ---
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState)
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose()
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.<>c__DisplayClass15_0.<GetExportedValueHelper>b__0()
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportElement(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import, RuntimeExport export, Func`3 lazyFactory)
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.GetValueForImportSite(RuntimePartLifecycleTracker importingPartTracker, RuntimeImport import)
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.<CreateValue>b__10_0(RuntimeImport import)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState)
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose()
   at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass53_0.<CreateExport>b__0()
   at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass55_0.<CreateExportFactoryExport>b__1()
   at Microsoft.VisualStudio.Composition.ExportProvider.<>c__DisplayClass54_0.<CreateExportFactory>b__0()
   at Microsoft.VisualStudio.Composition.DelegateServices.<>c__DisplayClass2_0`1.<As>b__0()
   at System.ComponentModel.Composition.ExportFactory`1.CreateExport()
   at Microsoft.VisualStudio.Composition.NetFxAdapters.MefV1ExportProvider.ComposablePartDefinitionForExportFactory.CreatePart()
   at System.ComponentModel.Composition.ReflectionModel.ExportFactoryCreator.LifetimeContext.GetExportLifetimeContextFromExport[T](Export export)
   at System.ComponentModel.Composition.ReflectionModel.ExportFactoryCreator.<>c__DisplayClass6_0`2.<CreateStronglyTypedExportFactoryOfTM>b__0()
   at System.ComponentModel.Composition.ExportFactory`1.CreateExport()
   at Microsoft.TeamFoundation.Controls.WPF.TeamExplorer.Framework.TeamExplorerSectionHost.Create()

[jcansdale]

@xperiandri Thanks for the stack trace.

It appears to be throwing on this line:

VisualStudio/src/GitHub.TeamFoundation.14/Base/TeamExplorerServiceHolder.cs

Line 38 in 0b7f956

gitService.ActiveRepositoriesChanged += UpdateActiveRepo;

which means this is returning null:

VisualStudio/src/GitHub.VisualStudio/GitHubPackage.cs

Line 132 in 0b7f956

public IVSGitExt VSGitExt => GetService<IVSGitExt>();

This would be expected on Blend because all non-MS services are disabled (IVSGitExt is one of ours).

The [ExportForProcess(typeof(IVSGitExt), ProcessName)] attribute should mean IVSGitExt only gets exported when running inside a process called devenv (ProcessName == "devenv").

I wonder if the Blend process has recently changed to be called devenv (the same as Visual Studio)? This would explain the NullReferenceException. 😕

[jcansdale]

@xperiandri, could you see if you have any more joy with this build:
https://ci.appveyor.com/api/buildjobs/kdj5vkh5xne35oiu/artifacts/2.5.1.2372%2FGitHub.VisualStudio.vsix

[jcansdale]

Oops, prematurely closed. #1649 is a step in the right direction, but I don't think it's a complete fix.

[jcansdale]

I'm still seeing the following with the build from #1649:

Microsoft.VisualStudio.Composition.CompositionFailedException: An exception was thrown while initializing part "GitHub.Services.VSGitServices". ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at GitHub.Services.VSGitServices..ctor(IGitHubServiceProvider serviceProvider) in C:\projects\visualstudio\src\GitHub.TeamFoundation.14\Services\VSGitServices.cs:line 54
   --- End of inner exception stack trace ---
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.RuntimePartLifecycleTracker.CreateValue()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.Create()
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.MoveNext(PartLifecycleState nextState)
   at Microsoft.VisualStudio.Composition.ExportProvider.PartLifecycleTracker.GetValueReadyToExpose()
   at Microsoft.VisualStudio.Composition.RuntimeExportProviderFactory.RuntimeExportProvider.<>c__DisplayClass15_0.<GetExportedValueHelper>b__0()

[jcansdale]

Hi folks. I've got a fix for you to try (from #1651). This one works with Blend 2017 on my machine. There was a regression.
https://ci.appveyor.com/api/buildjobs/ert9i2yy9ie27y8i/artifacts/2.5.1.2385%2FGitHub.VisualStudio.vsix

Let me know how you get on. Feel free to comment on the PR.