Port completion resolve to cohosting

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

@@ -0,0 +1,10 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.ComponentModel.Composition;
+using Microsoft.CodeAnalysis.Razor.Completion;
+
+namespace Microsoft.VisualStudio.Razor.LanguageClient.Cohost;
+
+[Export(typeof(CompletionListCache))]
+internal class CohostCompletionListCache : CompletionListCache;

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

@@ -43,6 +43,7 @@ internal sealed class CohostDocumentCompletionEndpoint(
     SnippetCompletionItemProvider snippetCompletionItemProvider,
     LanguageServerFeatureOptions languageServerFeatureOptions,
     LSPRequestInvoker requestInvoker,
+    CompletionListCache completionListCache,
     ILoggerFactory loggerFactory)
     : AbstractRazorCohostDocumentRequestHandler<RoslynCompletionParams, VSInternalCompletionList?>, IDynamicRegistrationProvider
 {
@@ -52,6 +53,7 @@ internal sealed class CohostDocumentCompletionEndpoint(
     private readonly SnippetCompletionItemProvider _snippetCompletionItemProvider = snippetCompletionItemProvider;
     private readonly CompletionTriggerAndCommitCharacters _triggerAndCommitCharacters = new(languageServerFeatureOptions);
     private readonly LSPRequestInvoker _requestInvoker = requestInvoker;
+    private readonly CompletionListCache _completionListCache = completionListCache;
     private readonly ILogger _logger = loggerFactory.GetOrCreateLogger<CohostDocumentCompletionEndpoint>();
 
     protected override bool MutatesSolutionState => false;
@@ -211,9 +213,10 @@ public ImmutableArray<Registration> GetRegistrations(VSInternalClientCapabilitie
             return null;
         }
 
+        var originalTdi = request.TextDocument;
         request.TextDocument = RoslynLspExtensions.WithUri(request.TextDocument, htmlDocument.Uri);
 
-        _logger.LogDebug($"Resolving auto-insertion edit for {htmlDocument.Uri}");
+        _logger.LogDebug($"Getting completion list for {htmlDocument.Uri} at {request.Position}");
 
         var result = await _requestInvoker.ReinvokeRequestOnServerAsync<RoslynCompletionParams, VSInternalCompletionList?>(
             htmlDocument.Buffer,
@@ -224,6 +227,14 @@ public ImmutableArray<Registration> GetRegistrations(VSInternalClientCapabilitie
 
         var rewrittenResponse = DelegatedCompletionHelper.RewriteHtmlResponse(result?.Response, razorCompletionOptions);
 
+        var completionCapability = _clientCapabilitiesService.ClientCapabilities.TextDocument?.Completion as VSInternalCompletionSetting;
+
+        var textDocument = JsonHelpers.ToVsLSP<TextDocumentIdentifier, RoslynTextDocumentIdentifier>(originalTdi).AssumeNotNull();
+        var razorDocumentIdentifier = new TextDocumentIdentifierAndVersion(textDocument, Version: 0);
+        var resolutionContext = new DelegatedCompletionResolutionContext(razorDocumentIdentifier, RazorLanguageKind.Html, rewrittenResponse.Data);
+        var resultId = _completionListCache.Add(rewrittenResponse, resolutionContext);
+        rewrittenResponse.SetResultId(resultId, completionCapability);
+
         return rewrittenResponse;
     }
 

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

@@ -584,13 +584,15 @@ private async Task VerifyCompletionListAsync(
         var snippetInfos = snippetLabels.Select(label => new SnippetInfo(label, label, label, string.Empty, SnippetLanguage.Html)).ToImmutableArray();
         snippetCompletionItemProvider.SnippetCache.Update(SnippetLanguage.Html, snippetInfos);
 
+        var completionListCache = new CompletionListCache();
         var endpoint = new CohostDocumentCompletionEndpoint(
             RemoteServiceInvoker,
             clientSettingsManager,
             TestHtmlDocumentSynchronizer.Instance,
             snippetCompletionItemProvider,
             TestLanguageServerFeatureOptions.Instance,
             requestInvoker,
+            completionListCache,
             LoggerFactory);
 
         var request = new RoslynCompletionParams()