[NETSDKE2E] Deleting an open razor file crashes LSP

[vsccarl]

Describe the Issue

Using C# and C# Dev Kit extensions, if I open a razor file, then delete it using solution explorer, I get a project load error.

Steps To Reproduce

Using the latest main builds of C# and C# Dev Kit with .NET 8 or .NET 9

1. Open a folder with a razor/blazor solution
2. Open a razor file in the editor
3. Delete the currently open file using Solution Explorer

Actual:

2025-08-04 23:34:40.878 [info] [Error - 11:34:40 PM] [razor/documentClosed] [LSP] System.InvalidOperationException: Expected 'requestContext.DocumentUri' to be non-null.
 File='/_/src/Razor/src/Microsoft.VisualStudioCode.RazorExtension/Endpoints/RazorDocumentClosedEndpoint.cs', Line=33
   at Microsoft.AspNetCore.Razor.ThrowHelper.ThrowInvalidOperationException(String message)
   at Microsoft.AspNetCore.Razor.Assumed.ThrowInvalidOperation(String message, String path, Int32 line)
   at Microsoft.AspNetCore.Razor.NullableExtensions.AssumeNotNull[T](T value, String message, String valueExpression, String path, Int32 line)
   at Microsoft.VisualStudioCode.RazorExtension.Endpoints.RazorDocumentClosedEndpoint.HandleRequestAsync(TextDocumentIdentifier textDocument, RazorCohostRequestContext requestContext, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost.AbstractRazorCohostRequestHandler`2.Microsoft.CommonLanguageServerProtocol.Framework.IRequestHandler<TRequestType,TResponseType,Microsoft.CodeAnalysis.LanguageServer.Handler.RequestContext>.HandleRequestAsync(TRequestType request, RequestContext context, CancellationToken cancellationToken) in /_/src/Tools/ExternalAccess/Razor/Features/Cohost/AbstractRazorRequestHandler.cs:line 21
   at Microsoft.CommonLanguageServerProtocol.Framework.QueueItem`1.StartRequestAsync[TRequest,TResponse](TRequest request, TRequestContext context, IMethodHandler handler, String language, CancellationToken cancellationToken) in /_/src/LanguageServer/Microsoft.CommonLanguageServerProtocol.Framework/QueueItem.cs:line 191
2025-08-04 23:34:40.884 [error] Error making razor/documentClosed request Expected 'requestContext.DocumentUri' to be non-null.

Expected Behavior

The language server does not crash.

Environment Information

OS: Win x64 and MacOS x64/arm64
.NET 8 or .NET 9 latest public releases

[claudiaregio]

@vsccarl Do you see the same behavior with VS?

[vsccarl]

@claudiaregio I do not see this happening in VS.

[claudiaregio]

@dibarbet or @Michael-Eng to take a look here

[dibarbet]

The stack is in the language server, but from Razor, moving over to them, cc @davidwengier

[davidwengier]

That's a weird stack, I would have expected it to fail in GetTextDocumentIdentifier before this. Nevermind, silly little mistake, easy fix.