Minor RazorProjectService cleanup (#10342)

With recent changes, this is unnecessary because a document add event
will do the same job, but better.

Author: davidwengier

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/RazorProjectService.cs

@@ -68,16 +68,6 @@ private void AddDocumentToMiscProjectCore(ProjectSnapshotManager.Updater updater
         _logger.LogInformation($"Adding document '{filePath}' to project '{miscFilesProject.Key}'.");
 
         updater.DocumentAdded(miscFilesProject.Key, hostDocument, textLoader);
-
-        // Adding a document to a project could also happen because a target was added to a project, or we're moving a document
-        // from Misc Project to a real one, and means the newly added document could actually already be open.
-        // If it is, we need to make sure we start generating it so we're ready to handle requests that could start coming in.
-        if (_projectManager.IsDocumentOpen(textDocumentPath) &&
-            _projectManager.TryGetLoadedProject(miscFilesProject.Key, out var project) &&
-            project.GetDocument(textDocumentPath) is { } document)
-        {
-            document.GetGeneratedOutputAsync().Forget();
-        }
     }
 
     public Task OpenDocumentAsync(string filePath, SourceText sourceText, int version, CancellationToken cancellationToken)

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/OpenDocumentGeneratorTest.cs

@@ -27,6 +27,37 @@ public class OpenDocumentGeneratorTest(ITestOutputHelper testOutput) : LanguageS
     private readonly HostProject _hostProject1 = new("c:/Test1/Test1.csproj", "c:/Test1/obj", RazorConfiguration.Default, "TestRootNamespace");
     private readonly HostProject _hostProject2 = new("c:/Test2/Test2.csproj", "c:/Test2/obj", RazorConfiguration.Default, "TestRootNamespace");
 
+    [Fact]
+    public async Task DocumentAdded_ProcessesOpenDocument()
+    {
+        // Arrange
+        var projectManager = CreateProjectSnapshotManager(new LspProjectEngineFactoryProvider(TestRazorLSPOptionsMonitor.Create()));
+        var listener = new TestDocumentProcessedListener();
+        using var generator = CreateOpenDocumentGenerator(projectManager, listener);
+
+        await projectManager.UpdateAsync(updater =>
+        {
+            updater.ProjectAdded(_hostProject1);
+            updater.ProjectAdded(_hostProject2);
+            updater.DocumentAdded(_hostProject1.Key, _documents[0], null!);
+            updater.DocumentOpened(_hostProject1.Key, _documents[0].FilePath, SourceText.From(string.Empty));
+        });
+
+        await listener.GetProcessedDocumentAsync(cancelAfter: TimeSpan.FromSeconds(10));
+        listener.Reset();
+
+        await projectManager.UpdateAsync(updater =>
+        {
+            updater.DocumentRemoved(_hostProject1.Key, _documents[0]);
+            updater.DocumentAdded(_hostProject2.Key, _documents[0], null!);
+        });
+
+        // Assert
+        var document = await listener.GetProcessedDocumentAsync(cancelAfter: TimeSpan.FromSeconds(10));
+        Assert.Equal(_hostProject2.Key, document.Project.Key);
+        Assert.Equal(_documents[0].FilePath, document.FilePath);
+    }
+
     [Fact]
     public async Task DocumentAdded_IgnoresClosedDocument()
     {
@@ -152,7 +183,7 @@ private OpenDocumentGenerator CreateOpenDocumentGenerator(
 
     private class TestDocumentProcessedListener : IDocumentProcessedListener
     {
-        private readonly TaskCompletionSource<IDocumentSnapshot> _tcs;
+        private TaskCompletionSource<IDocumentSnapshot> _tcs;
 
         public TestDocumentProcessedListener()
         {
@@ -178,5 +209,10 @@ public void DocumentProcessed(RazorCodeDocument codeDocument, IDocumentSnapshot
         {
             _tcs.SetResult(document);
         }
+
+        internal void Reset()
+        {
+            _tcs = new TaskCompletionSource<IDocumentSnapshot>();
+        }
     }
 }