Razor Language Server suddenly fails with DirectoryNotFound exception after moving some files.

Issue Description

Razor Language Server looks for files in directories no longer present and throws DirectoryNotFound exception. The location of the files is not referred to in any .csproj, and the project builds and runs just fine.

Environment data

dotnet --info output:

.NET Core SDK (reflecting any global.json):
 Version:   3.1.300
 Commit:    b2475c1295

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.15
 OS Platform: Darwin
 RID:         osx.10.15-x64
 Base Path:   /usr/local/share/dotnet/sdk/3.1.300/

Host (useful for support):
  Version: 3.1.4
  Commit:  0c2e69caa6

.NET Core SDKs installed:
  3.1.300 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.App 3.1.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

VS Code version: 1.45.1

C# Extension version: 1.22.0

OmniSharp log — Razor

Unhandled exception. System.IO.DirectoryNotFoundException: Could not find a part of the path '/Users/nikolaidamm/Repos/Work/BusinessUMLCreator/src/UI/BlazorSVG/Debugging/DebugGrid.razor'.
   at Interop.ThrowExceptionForIoErrno(ErrorInfo errorInfo, String path, Boolean isDirectory, Func`2 errorRewriter)
   at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String path, OpenFlags flags, Int32 mode)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
   at Microsoft.AspNetCore.Razor.LanguageServer.Common.DefaultRemoteTextLoaderFactory.RemoteTextLoader.LoadTextAndVersionAsync(Workspace workspace, DocumentId documentId, CancellationToken cancellationToken) in /_/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer.Common/DefaultRemoteTextLoaderFactory.cs:line 62
   at Microsoft.CodeAnalysis.Razor.ProjectSystem.DefaultProjectSnapshotManager.<>c__DisplayClass17_0.<DocumentAdded>b__0() in /_/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DefaultProjectSnapshotManager.cs:line 152
   at Microsoft.CodeAnalysis.Razor.ProjectSystem.DocumentState.GetTextVersionAsync() in /_/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DocumentState.cs:line 131
   at Microsoft.CodeAnalysis.Razor.ProjectSystem.DocumentState.ComputedStateTracker.GetGeneratedOutputAndVersionCoreAsync(DefaultProjectSnapshot project, DocumentSnapshot document) in /_/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DocumentState.cs:line 352
   at Microsoft.CodeAnalysis.Razor.ProjectSystem.DefaultDocumentSnapshot.GetGeneratedOutputAsync() in /_/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DefaultDocumentSnapshot.cs:line 63
   at Microsoft.AspNetCore.Razor.LanguageServer.RazorDiagnosticsPublisher.PublishDiagnosticsAsync(DocumentSnapshot document) in /_/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorDiagnosticsPublisher.cs:line 161
   at Microsoft.AspNetCore.Razor.LanguageServer.RazorDiagnosticsPublisher.WorkTimer_Tick(Object state) in /_/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/RazorDiagnosticsPublisher.cs:line 204
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__139_1(Object state)
   at System.Threading.QueueUserWorkItemCallbackDefaultContext.Execute()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
[Error - 2:21:35 PM] Connection to server got closed. Server will not be restarted.

Steps to reproduce

1. Open VSCode
2. Open workspace with the project that fails
3. Wait
4. Razor Language Server fails five times and closes.

I can add the directories and empty files, after which the problem will disappear, but if I delete them again, the problem resurfaces immediately.

Expected behavior

I’d expect the language server not to look for those files after I have moved them. It seems some data is cached, and I can’t figure out how to clean it, so it looks at the project structure as is, and not as was.

Actual behavior

It looks for files even though I have moved them, and fails when it can’t find them.

[devantler]

The problem still happens way too often. It seems to be triggered by changing branches. It, for example, occurs when I switch from a branch that has one specific folder structure to one with changes to that folder structure.

The result is still the error above as the Razor Language Server fails to find the folder/file, as it has changed location on the new branch.

A way to reset the Language Server to its initial state (the one it has when opening a “brand new” project) would be helpful until this has been stabilized.

[devantler]

Deleting the project from disk, and cloning it from GitHub fixed the issue.