Fix Duplicate Links in Auto Curated API Collections (#1021)

* Remove extra commas from MixedLanguageFramework.symbols.json fixtures

* DocumentationContext#registerSymbols passes a unique set of
relationships to GeneratedDocumentationTopics.createInheritedSymbolsAPICollections.

* Rewrite unit test, avoiding manual changes
to symbol graph fixture files

rdar://133964293

Author: patshaughnessy

Sources/SwiftDocC/Infrastructure/DocumentationContext.swift

@@ -1092,7 +1092,9 @@ public class DocumentationContext: DocumentationContextDataProviderDelegate {
         // Making sure that we correctly let decoding memory get released, do not remove the autorelease pool.
         try autoreleasepool {
             /// We need only unique relationships so we'll collect them in a set.
-            var combinedRelationships = [UnifiedSymbolGraph.Selector: Set<SymbolGraph.Relationship>]()
+            var combinedRelationshipsBySelector = [UnifiedSymbolGraph.Selector: Set<SymbolGraph.Relationship>]()
+            /// Also track the unique relationships across all languages and platforms
+            var uniqueRelationships = Set<SymbolGraph.Relationship>()
             /// Collect symbols from all symbol graphs.
             var combinedSymbols = [String: UnifiedSymbolGraph.Symbol]()
 
@@ -1106,7 +1108,8 @@ public class DocumentationContext: DocumentationContextDataProviderDelegate {
             documentLocationMap.reserveCapacity(symbolReferences.count)
             topicGraph.nodes.reserveCapacity(symbolReferences.count)
             topicGraph.edges.reserveCapacity(symbolReferences.count)
-            combinedRelationships.reserveCapacity(symbolReferences.count)
+            combinedRelationshipsBySelector.reserveCapacity(symbolReferences.count)
+            uniqueRelationships.reserveCapacity(symbolReferences.count)
             combinedSymbols.reserveCapacity(symbolReferences.count)
 
             // Iterate over batches of symbol graphs, each batch describing one module.
@@ -1207,15 +1210,17 @@ public class DocumentationContext: DocumentationContextDataProviderDelegate {
                 combinedSymbols.merge(unifiedSymbolGraph.symbols, uniquingKeysWith: { $1 })
 
                 for (selector, relationships) in unifiedSymbolGraph.relationshipsByLanguage {
-                    combinedRelationships[selector, default: []].formUnion(relationships)
+                    combinedRelationshipsBySelector[selector, default: []].formUnion(relationships)
+                    uniqueRelationships.formUnion(relationships)
                 }
 
                 // Keep track of relationships that refer to symbols that are absent from the symbol graph, so that
                 // we can diagnose them.
-                combinedRelationships[
+                combinedRelationshipsBySelector[
                     .init(interfaceLanguage: "unknown", platform: nil),
                     default: []
                 ].formUnion(unifiedSymbolGraph.orphanRelationships)
+                uniqueRelationships.formUnion(unifiedSymbolGraph.orphanRelationships)
             }
 
             try shouldContinueRegistration()
@@ -1305,10 +1310,10 @@ public class DocumentationContext: DocumentationContextDataProviderDelegate {
             }
             emitWarningsForSymbolsMatchedInMultipleDocumentationExtensions(with: symbolsWithMultipleDocumentationExtensionMatches)
             symbolsWithMultipleDocumentationExtensionMatches.removeAll()
-            
+
             // Create inherited API collections
             try GeneratedDocumentationTopics.createInheritedSymbolsAPICollections(
-                relationships: combinedRelationships.flatMap(\.value),
+                relationships: uniqueRelationships,
                 context: self,
                 bundle: bundle
             )
@@ -1350,9 +1355,9 @@ public class DocumentationContext: DocumentationContextDataProviderDelegate {
             preResolveExternalLinks(references: Array(moduleReferences.values) + combinedSymbols.keys.compactMap({ documentationCache.reference(symbolID: $0) }), localBundleID: bundle.identifier)
 
             // Look up and add symbols that are _referenced_ in the symbol graph but don't exist in the symbol graph.
-            try resolveExternalSymbols(in: combinedSymbols, relationships: combinedRelationships)
+            try resolveExternalSymbols(in: combinedSymbols, relationships: combinedRelationshipsBySelector)
 
-            for (selector, relationships) in combinedRelationships {
+            for (selector, relationships) in combinedRelationshipsBySelector {
                 // Build relationships in the completed graph
                 buildRelationships(relationships, selector: selector, bundle: bundle)
                 // Merge into target symbols the member symbols that get rendered on the same page as target.

Sources/SwiftDocC/Infrastructure/Symbol Graph/GeneratedDocumentationTopics.swift

@@ -231,7 +231,7 @@ enum GeneratedDocumentationTopics {
     ///   - symbolsURLHierarchy: A symbol graph hierarchy as created during symbol registration.
     ///   - context: A documentation context to update.
     ///   - bundle: The current documentation bundle.
-    static func createInheritedSymbolsAPICollections(relationships: [SymbolGraph.Relationship], context: DocumentationContext, bundle: DocumentationBundle) throws {
+    static func createInheritedSymbolsAPICollections(relationships: Set<SymbolGraph.Relationship>, context: DocumentationContext, bundle: DocumentationBundle) throws {
         var inheritanceIndex = InheritedSymbols()
 
         // Walk the symbol graph relationships and look for parent <-> child links that stem in a different module.

Tests/SwiftDocCTests/Infrastructure/AutomaticCurationTests.swift

@@ -448,7 +448,56 @@ class AutomaticCurationTests: XCTestCase {
             )
         }
     }
-    
+
+    func testNoAutoCuratedMixedLanguageDuplicates() throws {
+        let (_, bundle, context) = try testBundleAndContext(copying: "MixedLanguageFramework") { url in
+
+            // Load the existing Obj-C symbol graph from this fixture.
+            let path = "symbol-graphs/clang/MixedLanguageFramework.symbols.json"
+            var graph = try JSONDecoder().decode(SymbolGraph.self, from: Data(contentsOf: url.appendingPathComponent(path)))
+
+            // Add an Objective-C relationship between MixedLanguageClassConformingToProtocol.mixedLanguageMethod
+            // and the protocol requirement: MixedLanguageProtocol.mixedLanguageMethod. This matches an existing
+            // Swift relationship, causing duplicate memberOf relationships.
+            var relationship = SymbolGraph.Relationship(
+                source: "c:@CM@TestFramework@objc(cs)MixedLanguageClassConformingToProtocol(im)mixedLanguageMethod",
+                target: "c:@M@TestFramework@objc(cs)MixedLanguageClassConformingToProtocol",
+                kind: .memberOf,
+                targetFallback: nil
+            )
+            relationship.mixins["sourceOrigin"] = SymbolKit.SymbolGraph.Relationship.SourceOrigin(
+                identifier: "c:@M@TestFramework@objc(pl)MixedLanguageProtocol(im)mixedLanguageMethod",
+                displayName: "MixedLanguageProtocol.mixedLanguageMethod()"
+            )
+            graph.relationships.append(relationship)
+            let newGraphData = try JSONEncoder().encode(graph)
+            try newGraphData.write(to: url.appendingPathComponent("symbol-graphs/clang/MixedLanguageFramework.symbols.json"))
+        }
+
+        // Load the "MixedLanguageProtocol Implementations" API COllection
+        let protocolImplementationsNode = try context.entity(
+            with: ResolvedTopicReference(
+                bundleIdentifier: bundle.identifier,
+                path: "/documentation/MixedLanguageFramework/MixedLanguageClassConformingToProtocol/MixedLanguageProtocol-Implementations",
+                sourceLanguages: [.swift, .objectiveC]
+            )
+        )
+
+        // This page should contain an auto-curated "Instance Methods" task group.
+        let protocolImplementationsArticle = try XCTUnwrap(protocolImplementationsNode.semantic as? Article)
+        XCTAssertEqual(1, protocolImplementationsArticle.automaticTaskGroups.count)
+        let instanceMethodsTaskGroup = protocolImplementationsArticle.automaticTaskGroups.first!
+        XCTAssertEqual("Instance Methods", instanceMethodsTaskGroup.title)
+
+        // And this task group should contain only one reference, to a combined Swift/Obj-C child node.
+        XCTAssertEqual(1, instanceMethodsTaskGroup.references.count)
+        let ref = instanceMethodsTaskGroup.references.first!
+        XCTAssertEqual(
+            "doc://org.swift.MixedLanguageFramework/documentation/MixedLanguageFramework/MixedLanguageClassConformingToProtocol/mixedLanguageMethod()",
+            ref.absoluteString
+        )
+    }
+
     func testRelevantLanguagesAreAutoCuratedInMixedLanguageFramework() throws {
         let (bundle, context) = try testBundleAndContext(named: "MixedLanguageFramework")
 
@@ -465,7 +514,7 @@ class AutomaticCurationTests: XCTestCase {
             withTraits: [.swift],
             context: context
         )
-        
+
         XCTAssertEqual(
             swiftTopics.flatMap { taskGroup in
                 [taskGroup.title] + taskGroup.references.map(\.path)