Support ItemDefaults.Data on completion lists

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Completion/Delegation/DelegatedCompletionListProvider.cs

@@ -117,7 +117,7 @@ internal class DelegatedCompletionListProvider(
             : DelegatedCompletionHelper.RewriteHtmlResponse(delegatedResponse, razorCompletionOptions);
 
         var completionCapability = clientCapabilities?.TextDocument?.Completion as VSInternalCompletionSetting;
-        var resolutionContext = new DelegatedCompletionResolutionContext(identifier, positionInfo.LanguageKind, rewrittenResponse.Data);
+        var resolutionContext = new DelegatedCompletionResolutionContext(identifier, positionInfo.LanguageKind, rewrittenResponse.Data ?? rewrittenResponse.ItemDefaults?.Data);
         var resultId = _completionListCache.Add(rewrittenResponse, resolutionContext);
         rewrittenResponse.SetResultId(resultId, completionCapability);
 

src/Razor/src/Microsoft.CodeAnalysis.Razor.CohostingShared/Completion/CohostDocumentCompletionEndpoint.cs

@@ -239,7 +239,7 @@ public ImmutableArray<Registration> GetRegistrations(VSInternalClientCapabilitie
         var completionCapability = _clientCapabilitiesService.ClientCapabilities.TextDocument?.Completion as VSInternalCompletionSetting;
 
         var razorDocumentIdentifier = new TextDocumentIdentifierAndVersion(request.TextDocument, Version: 0);
-        var resolutionContext = new DelegatedCompletionResolutionContext(razorDocumentIdentifier, RazorLanguageKind.Html, rewrittenResponse.Data);
+        var resolutionContext = new DelegatedCompletionResolutionContext(razorDocumentIdentifier, RazorLanguageKind.Html, rewrittenResponse.Data ?? rewrittenResponse.ItemDefaults?.Data);
         var resultId = _completionListCache.Add(rewrittenResponse, resolutionContext);
         rewrittenResponse.SetResultId(resultId, completionCapability);
 

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/CompletionListMerger.cs

@@ -45,6 +45,7 @@ internal static class CompletionListMerger
         // We don't fully support merging continue characters currently. Razor doesn't currently use them so delegated completion lists always win.
         var mergedContinueWithCharacters = razorCompletionList.ContinueCharacters ?? delegatedCompletionList.ContinueCharacters;
 
+        var mergedItemDefaultsData = MergeData(razorCompletionList.ItemDefaults?.Data, delegatedCompletionList.ItemDefaults?.Data);
         // We don't fully support merging edit ranges currently. Razor doesn't currently use them so delegated completion lists always win.
         var mergedItemDefaultsEditRange = razorCompletionList.ItemDefaults?.EditRange ?? delegatedCompletionList.ItemDefaults?.EditRange;
 
@@ -58,6 +59,7 @@ internal static class CompletionListMerger
             ContinueCharacters = mergedContinueWithCharacters,
             ItemDefaults = new CompletionListItemDefaults()
             {
+                Data = mergedItemDefaultsData,
                 EditRange = mergedItemDefaultsEditRange,
             }
         };
@@ -152,14 +154,16 @@ private static void TrySplitJsonElement(object data, ref PooledArrayBuilder<Json
 
     private static void EnsureMergeableData(RazorVSInternalCompletionList completionListA, RazorVSInternalCompletionList completionListB)
     {
-        if (completionListA.Data != completionListB.Data &&
-            (completionListA.Data is null || completionListB.Data is null))
+        var completionListAData = completionListA.Data ?? completionListA.ItemDefaults?.Data;
+        var completionListBData = completionListB.Data ?? completionListB.ItemDefaults?.Data;
+        if (completionListAData != completionListBData &&
+            (completionListAData is null || completionListBData is null))
         {
             // One of the completion lists have data while the other does not, we need to ensure that any non-data centric items don't get incorrect data associated
 
             // The candidate completion list will be one where we populate empty data for any `null` specifying data given we'll be merging
             // two completion lists together we don't want incorrect data to be inherited down
-            var candidateCompletionList = completionListA.Data is null ? completionListA : completionListB;
+            var candidateCompletionList = completionListAData is null ? completionListA : completionListB;
             for (var i = 0; i < candidateCompletionList.Items.Length; i++)
             {
                 var item = candidateCompletionList.Items[i];

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/RazorCompletionResolveData.cs

@@ -37,8 +37,17 @@ public static void Wrap(VSInternalCompletionList completionList, TextDocumentIde
 
         if (supportsCompletionListData)
         {
-            // Can set data at the completion list level
-            completionList.Data = data with { OriginalData = completionList.Data };
+            if (completionList.Data is not null)
+            {
+                // Can set data at the completion list level
+                completionList.Data = data with { OriginalData = completionList.Data };
+            }
+
+            if (completionList.ItemDefaults?.Data is not null)
+            {
+                // Set data for the item defaults
+                completionList.ItemDefaults.Data = data with { OriginalData = completionList.ItemDefaults.Data };
+            }
 
             // Set data for items that won't inherit the default
             foreach (var completionItem in completionList.Items.Where(static c => c.Data is not null))

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/VSInternalCompletionListExtensions.cs

@@ -4,6 +4,7 @@
 using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Nodes;
+using Microsoft.AspNetCore.Razor;
 
 namespace Microsoft.CodeAnalysis.Razor.Completion;
 
@@ -24,26 +25,31 @@ public static void SetResultId(
 
         if (completionSetting.SupportsCompletionListData())
         {
-            // Can set data at the completion list level
+            // Ensure there is data at the completion list level, but only if ItemDefaults isn't set by the delegated server,
+            // or if they've set both.
+            var hasDefaultsData = completionList.ItemDefaults?.Data is not null;
+            if (completionList.Data is not null || !hasDefaultsData)
+            {
+                completionList.Data = CompletionListMerger.MergeData(data, completionList.Data);
+            }
 
-            var mergedData = CompletionListMerger.MergeData(data, completionList.Data);
-            completionList.Data = mergedData;
+            if (hasDefaultsData)
+            {
+                completionList.ItemDefaults.AssumeNotNull().Data = CompletionListMerger.MergeData(data, completionList.ItemDefaults.Data);
+            }
 
             // Merge data for items that won't inherit the default
             foreach (var completionItem in completionList.Items.Where(c => c.Data is not null))
             {
-                mergedData = CompletionListMerger.MergeData(data, completionItem.Data);
-                completionItem.Data = mergedData;
+                completionItem.Data = CompletionListMerger.MergeData(data, completionItem.Data);
             }
         }
         else
         {
             // No CompletionList.Data support
-
             foreach (var completionItem in completionList.Items)
             {
-                var mergedData = CompletionListMerger.MergeData(data, completionItem.Data);
-                completionItem.Data = mergedData;
+                completionItem.Data = CompletionListMerger.MergeData(data, completionItem.Data);
             }
         }
     }

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/Completion/RemoteCompletionService.cs

@@ -236,7 +236,7 @@ private async ValueTask<Response> GetCompletionAsync(
 
         var completionCapability = clientCapabilities?.TextDocument?.Completion as VSInternalCompletionSetting;
 
-        var resolutionContext = new DelegatedCompletionResolutionContext(identifier, RazorLanguageKind.CSharp, rewrittenResponse.Data);
+        var resolutionContext = new DelegatedCompletionResolutionContext(identifier, RazorLanguageKind.CSharp, rewrittenResponse.Data ?? rewrittenResponse.ItemDefaults?.Data);
         var resultId = _completionListCache.Add(rewrittenResponse, resolutionContext);
         rewrittenResponse.SetResultId(resultId, completionCapability);