Allow publishing to fail, and just report that we're not synchronized

src/Razor/src/Microsoft.CodeAnalysis.Razor.CohostingShared/HtmlDocumentServices/HtmlDocumentSynchronizer.cs

@@ -162,8 +162,8 @@ private async Task<SynchronizationResult> PublishHtmlDocumentAsync(TextDocument
 
         try
         {
-            var result = new SynchronizationResult(true, requestedVersion.Checksum);
-            await _htmlDocumentPublisher.PublishAsync(document, result, htmlText, cancellationToken).ConfigureAwait(false);
+            var synchronized = await _htmlDocumentPublisher.TryPublishAsync(document, requestedVersion.Checksum, htmlText, cancellationToken).ConfigureAwait(false);
+            var result = new SynchronizationResult(Synchronized: synchronized, requestedVersion.Checksum);
 
             // If we were cancelled, we can't trust that the publish worked.
             if (cancellationToken.IsCancellationRequested)

src/Razor/src/Microsoft.CodeAnalysis.Razor.CohostingShared/HtmlDocumentServices/IHtmlDocumentPublisher.cs

@@ -4,10 +4,11 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 
 namespace Microsoft.VisualStudio.Razor.LanguageClient.Cohost;
 
 internal interface IHtmlDocumentPublisher
 {
-    Task PublishAsync(TextDocument document, SynchronizationResult synchronizationResult, string htmlText, CancellationToken cancellationToken);
+    Task<bool> TryPublishAsync(TextDocument document, ChecksumWrapper checksum, string htmlText, CancellationToken cancellationToken);
 }

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/LanguageClient/Cohost/HtmlDocumentPublisher.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Immutable;
 using System.ComponentModel.Composition;
-using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
@@ -29,22 +28,19 @@ internal sealed class HtmlDocumentPublisher(
     private readonly TrackingLSPDocumentManager _documentManager = documentManager as TrackingLSPDocumentManager ?? throw new InvalidOperationException("Expected TrackingLSPDocumentManager");
     private readonly ILogger _logger = loggerFactory.GetOrCreateLogger<HtmlDocumentPublisher>();
 
-    public async Task PublishAsync(TextDocument document, SynchronizationResult synchronizationResult, string htmlText, CancellationToken cancellationToken)
+    public async Task<bool> TryPublishAsync(TextDocument document, ChecksumWrapper checksum, string htmlText, CancellationToken cancellationToken)
     {
-        Assumed.True(synchronizationResult.Synchronized);
-
         var uri = document.CreateUri();
         if (!_documentManager.TryGetDocument(uri, out var documentSnapshot) ||
             !documentSnapshot.TryGetVirtualDocument<HtmlVirtualDocumentSnapshot>(out var htmlDocument))
         {
-            Debug.Fail("Got an LSP text document update before getting informed of the VS buffer. Create on demand?");
-            _logger.LogError($"Couldn't get Html text for {document.FilePath}. Html document contents will be stale");
-            return;
+            _logger.LogDebug($"No {(documentSnapshot is null ? "" : "virtual")} document snapshot for {document.FilePath}.");
+            return false;
         }
 
         if (cancellationToken.IsCancellationRequested)
         {
-            return;
+            return false;
         }
 
         _logger.LogDebug($"The html document for {document.FilePath} is {htmlDocument.Uri}");
@@ -53,7 +49,7 @@ public async Task PublishAsync(TextDocument document, SynchronizationResult sync
 
         if (cancellationToken.IsCancellationRequested)
         {
-            return;
+            return false;
         }
 
         // We have a string for the Html text here, so its tempting to just overwrite the whole buffer, but that causes issues with
@@ -63,8 +59,10 @@ public async Task PublishAsync(TextDocument document, SynchronizationResult sync
         var newHtmlSourceText = SourceText.From(htmlText, currentHtmlSourceText.Encoding, currentHtmlSourceText.ChecksumAlgorithm);
         var textChanges = SourceTextDiffer.GetMinimalTextChanges(currentHtmlSourceText, newHtmlSourceText);
         var changes = textChanges.SelectAsArray(c => new VisualStudioTextChange(c.Span.Start, c.Span.Length, c.NewText.AssumeNotNull()));
-        _documentManager.UpdateVirtualDocument<HtmlVirtualDocument>(uri, changes, documentSnapshot.Version, state: synchronizationResult.Checksum);
+        _documentManager.UpdateVirtualDocument<HtmlVirtualDocument>(uri, changes, documentSnapshot.Version, state: checksum);
 
         _logger.LogDebug($"Finished Html document generation for {document.FilePath} (into {htmlDocument.Uri})");
+
+        return true;
     }
 }

src/Razor/src/Microsoft.VisualStudioCode.RazorExtension/Services/HtmlDocumentPublisher.cs

@@ -20,14 +20,13 @@ internal sealed class HtmlDocumentPublisher(
 {
     private readonly RazorClientServerManagerProvider _razorClientServerManagerProvider = razorClientServerManagerProvider;
 
-    public async Task PublishAsync(TextDocument document, SynchronizationResult synchronizationResult, string htmlText, CancellationToken cancellationToken)
+    public async Task<bool> TryPublishAsync(TextDocument document, ChecksumWrapper checksum, string htmlText, CancellationToken cancellationToken)
     {
-        Assumed.True(synchronizationResult.Synchronized);
-
-        var request = new HtmlUpdateParameters(new TextDocumentIdentifier { DocumentUri = document.CreateDocumentUri() }, synchronizationResult.Checksum.ToString(), htmlText);
+        var request = new HtmlUpdateParameters(new TextDocumentIdentifier { DocumentUri = document.CreateDocumentUri() }, checksum.ToString(), htmlText);
 
         var clientConnection = _razorClientServerManagerProvider.ClientLanguageServerManager.AssumeNotNull();
         await clientConnection.SendRequestAsync("razor/updateHtml", request, cancellationToken).ConfigureAwait(false);
+        return true;
     }
 
     private record HtmlUpdateParameters(

src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Cohost/HtmlDocumentSynchronizerTest.cs

@@ -31,6 +31,18 @@ protected override void ConfigureWorkspace(AdhocWorkspace workspace)
         Assert.True(workspace.TryApplyChanges(document.Project.Solution));
     }
 
+    [Fact]
+    public async Task TrySynchronize_FailsIfPublishFails()
+    {
+        var document = Workspace.CurrentSolution.GetAdditionalDocument(_documentId).AssumeNotNull();
+
+        var publisher = new TestHtmlDocumentPublisher(publishResult: false);
+        var remoteServiceInvoker = new RemoteServiceInvoker(document);
+        var synchronizer = new HtmlDocumentSynchronizer(remoteServiceInvoker, publisher, LoggerFactory);
+
+        Assert.False((await synchronizer.TrySynchronizeAsync(document, DisposalToken)).Synchronized);
+    }
+
     [Fact]
     public async Task TrySynchronize_NewDocument_Generates()
     {

src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Cohost/TestHtmlDocumentPublisher.cs

@@ -9,13 +9,15 @@
 
 namespace Microsoft.VisualStudio.Razor.LanguageClient.Cohost;
 
-internal sealed class TestHtmlDocumentPublisher : IHtmlDocumentPublisher
+internal sealed class TestHtmlDocumentPublisher(bool publishResult = true) : IHtmlDocumentPublisher
 {
+    private readonly bool _publishResult = publishResult;
+
     public List<(TextDocument Document, string Text, ChecksumWrapper Checksum)> Publishes { get; } = [];
 
-    public Task PublishAsync(TextDocument document, SynchronizationResult synchronizationResult, string htmlText, CancellationToken cancellationToken)
+    public Task<bool> TryPublishAsync(TextDocument document, ChecksumWrapper checksum, string htmlText, CancellationToken cancellationToken)
     {
-        Publishes.Add((document, htmlText, synchronizationResult.Checksum));
-        return Task.CompletedTask;
+        Publishes.Add((document, htmlText, checksum));
+        return Task.FromResult(_publishResult);
     }
 }