NFW: InvalidOperationException: The project already references the target project.

[davkean]

This is the #4 highest non-fatal watson for the project-system, with 13% of all hits. This is a regression in 16.6-pre3.

Version Used:
16.6-pre3

Steps to Reproduce:

InvalidOperationException: The project already references the target project.
Microsoft.CodeAnalysis.Solution.AddProjectReferences(ProjectId,IEnumerable`1)
Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioProject.<>c__DisplayClass85_0.<OnBatchScopeDisposed>b__0(Solution)
Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioWorkspaceImpl.ApplyBatchChangeToWorkspace(Func`2)
Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioProject.OnBatchScopeDisposed()
Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.VisualStudioProject.BatchScope.Dispose()
Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem.CPS.CPSProject.EndBatch()
Microsoft.VisualStudio.ProjectSystem.LanguageServices.WorkspaceProjectContextHost.WorkspaceProjectContextHostInstance.<ApplyProjectChangesUnderLockAsync>d__19.MoveNext()
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.VisualStudio.Threading.ReentrantSemaphore.StackSemaphore.<>c__DisplayClass3_0.<<ExecuteAsync>b__0>d.MoveNext()
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.VisualStudio.Threading.AwaitExtensions.ExecuteContinuationSynchronouslyAwaiter.GetResult()
Microsoft.VisualStudio.Threading.ReentrantSemaphore.StackSemaphore.<ExecuteAsync>d__3.MoveNext()
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.VisualStudio.ProjectSystem.OnceInitializedOnceDisposedUnderLockAsync.<ExecuteUnderLockCoreAsync>d__7.MoveNext()
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.VisualStudio.ProjectSystem.DataReceivingBlockSlim`1.<ProcessInputQueueAsync>d__5.MoveNext()
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
Microsoft.VisualStudio.ProjectSystem.CommonProjectSystemTools.Rethrow(Exception)
Microsoft.VisualStudio.ProjectSystem.ProjectErrorReporting.<>c__DisplayClass6_0.<SubmitErrorReport>b__0()
Microsoft.VisualStudio.ProjectSystem.ExceptionFilter.<>c__DisplayClass2_0.<Guard>g__action|0()
GuardMethodClass.GuardMethod(Func`1,Func`2,Func`2)

[jasonmalinowski]

Is this a dupe of #39032?

[davkean]

Yes looks like it. We've started reporting it now, hence why showing up.

[davkean]

I think the EndBatch call was hiding this one, hence why its new for 16.3 pre3.

[davkean]

There might be a dump in dotnet/project-system#6141.

[davkean]

You'll need to pull uncollected exceptions off the stack/heap.