Feedback

Author: chsienki

src/Workspaces/Core/Portable/SourceGeneration/SourceGeneratorExtensions.cs

@@ -25,6 +25,7 @@ public static bool IsRequiredGenerator(this ISourceGenerator generator)
         // In the future we might want to expand this to e.g. run any generators with open generated files
         return generator.GetGeneratorType().FullName == "Microsoft.NET.Sdk.Razor.SourceGenerators.RazorSourceGenerator";
     }
+
     /// <summary>
     /// Determines the presence and type of source generators in the specified collection.
     /// </summary>
@@ -37,7 +38,7 @@ public static SourceGeneratorPresence GetSourceGeneratorPresence(this ImmutableA
 
         var hasRequiredGenerators = generators.Any(g => g.IsRequiredGenerator());
         return hasRequiredGenerators
-               ? SourceGeneratorPresence.ContainsRequiredSourceGenerators
-               : SourceGeneratorPresence.OnlyOptionalSourceGenerators;
+            ? SourceGeneratorPresence.ContainsRequiredSourceGenerators
+            : SourceGeneratorPresence.OnlyOptionalSourceGenerators;
     }
 }

src/Workspaces/Core/Portable/Workspace/Solution/SolutionCompilationState.RegularCompilationTracker_Generators.cs

@@ -36,10 +36,7 @@ private sealed partial class RegularCompilationTracker : ICompilationTracker
             Compilation? compilationWithStaleGeneratedTrees,
             CancellationToken cancellationToken)
         {
-            var canSkipRunningGenerators = creationPolicy.GeneratedDocumentCreationPolicy is GeneratedDocumentCreationPolicy.DoNotCreate
-                                           || (creationPolicy.GeneratedDocumentCreationPolicy is GeneratedDocumentCreationPolicy.CreateOnlyRequired
-                                               && !await HasRequiredGeneratorsAsync(compilationState, cancellationToken).ConfigureAwait(false));
-
+            var canSkipRunningGenerators = await CanSkipRunningGeneratorsAsync(creationPolicy, compilationState, cancellationToken).ConfigureAwait(false);
             if (canSkipRunningGenerators)
             {
                 // We're either frozen, or we only want required generators and know that there aren't any to run, so we
@@ -78,6 +75,23 @@ private sealed partial class RegularCompilationTracker : ICompilationTracker
                     cancellationToken).ConfigureAwait(false);
                 return (compilationWithGeneratedFiles, new(nextGeneratedDocuments, nextGeneratorDriver));
             }
+
+            async ValueTask<bool> CanSkipRunningGeneratorsAsync(CreationPolicy creationPolicy, SolutionCompilationState compilationState, CancellationToken cancellationToken)
+            {
+                // if we don't want to create generated documents, we can skip
+                if (creationPolicy.GeneratedDocumentCreationPolicy is GeneratedDocumentCreationPolicy.DoNotCreate)
+                    return true;
+
+                // if we only want required documents, we can skip if we don't have any required generators
+                if (creationPolicy.GeneratedDocumentCreationPolicy is GeneratedDocumentCreationPolicy.CreateOnlyRequired)
+                {
+                    var hasRequiredGenerators = await HasRequiredGeneratorsAsync(compilationState, cancellationToken).ConfigureAwait(false);
+                    return !hasRequiredGenerators;
+                }
+
+                // we need to run generators
+                return false;
+            }
         }
 
         private async Task<bool> HasRequiredGeneratorsAsync(SolutionCompilationState compilationState, CancellationToken cancellationToken)

src/Workspaces/Remote/ServiceHub/Services/SourceGeneration/RemoteSourceGenerationService.cs

@@ -123,21 +123,22 @@ public async ValueTask<SourceGeneratorPresence> GetSourceGeneratorPresenceAsync(
             () => assetProvider.GetAssetsArrayAsync<AnalyzerReference>(projectId, checksumCollection, cancellationToken),
             cancellationToken).ConfigureAwait(false);
 
+        // if we don't have any analyzer references then we don't have any generators
+        if (isolatedReferences.IsEmpty)
+            return SourceGeneratorPresence.NoSourceGenerators;
+
+        // see if any of the references have a required generator
         var (analyzerReferenceMap, callback) = s_languageToAnalyzerReferenceMap[language];
-        var hasGenerators = false;
         foreach (var analyzerReference in isolatedReferences)
         {
             var generatorPresence = analyzerReferenceMap.GetValue(analyzerReference, callback).Value;
 
             if (generatorPresence is SourceGeneratorPresence.ContainsRequiredSourceGenerators)
                 return SourceGeneratorPresence.ContainsRequiredSourceGenerators;
-
-            if (generatorPresence is SourceGeneratorPresence.OnlyOptionalSourceGenerators)
-                hasGenerators = true;
         }
 
-        return hasGenerators ? SourceGeneratorPresence.OnlyOptionalSourceGenerators
-                             : SourceGeneratorPresence.NoSourceGenerators;
+        // no required generators, all are optional
+        return SourceGeneratorPresence.OnlyOptionalSourceGenerators;
     }
 
     public ValueTask<ImmutableArray<SourceGeneratorIdentity>> GetSourceGeneratorIdentitiesAsync(