Use both URS and name to add symbols to the right language representation of their container symbol (#765)

rdar://119300362

Author: d-ronnqvist

Sources/SwiftDocC/Infrastructure/Link Resolution/PathHierarchy.swift

@@ -122,14 +122,18 @@ struct PathHierarchy {
 
             var topLevelCandidates = nodes
             for relationship in graph.relationships where relationship.kind.formsHierarchy {
-                guard let sourceNode = nodes[relationship.source] else {
+                guard let sourceNode = nodes[relationship.source], let expectedContainerName = sourceNode.symbol?.pathComponents.dropLast().last else {
                     continue
                 }
-                if let targetNode = nodes[relationship.target] {
+                // The relationship only specify the target symbol's USR but if the target symbol has different representations in different source languages the relationship
+                // alone doesn't specify which language representation the source symbol belongs to. We could check the source and target symbol's interface language but that
+                // would require that we redundantly create multiple nodes for the same symbol in many common cases and then merge them. To avoid doing that, we instead check
+                // the source symbol's path components to find the correct target symbol by matching its name.
+                if let targetNode = nodes[relationship.target], targetNode.name == expectedContainerName {
                     targetNode.add(symbolChild: sourceNode)
                     topLevelCandidates.removeValue(forKey: relationship.source)
                 } else if let targetNodes = allNodes[relationship.target] {
-                    for targetNode in targetNodes {
+                    for targetNode in targetNodes where targetNode.name == expectedContainerName {
                         targetNode.add(symbolChild: sourceNode)
                     }
                     topLevelCandidates.removeValue(forKey: relationship.source)

Tests/SwiftDocCTests/Infrastructure/PathHierarchyTests.swift

@@ -1575,7 +1575,7 @@ class PathHierarchyTests: XCTestCase {
         XCTAssertEqual(paths["X.Y2.Z.W"], "/Module/X/Y2/Z/W")
     }
 
-    func testMixedLanguageSymbolWithItsExtendingModule() throws {
+    func testMixedLanguageSymbolAndItsExtendingModule() throws {
         let containerID = "some-container-symbol-id"
         let memberID = "some-member-symbol-id"
 
@@ -1618,6 +1618,49 @@ class PathHierarchyTests: XCTestCase {
         XCTAssertEqual(paths[memberID], "/ModuleName/ContainerName/MemberName")
     }
 
+    func testMixedLanguageSymbolAndItsExtendingModuleWithDifferentContainerNames() throws {
+        let containerID = "some-container-symbol-id"
+        let memberID = "some-member-symbol-id"
+        
+        let exampleDocumentation = Folder(name: "unit-test.docc", content: [
+            Folder(name: "clang", content: [
+                JSONFile(name: "ModuleName.symbols.json", content: makeSymbolGraph(
+                    moduleName: "ModuleName",
+                    symbols: [
+                        (containerID, .objectiveC, ["ObjectiveCContainerName"])
+                    ]
+                )),
+            ]),
+            
+            Folder(name: "swift", content: [
+                JSONFile(name: "ModuleName.symbols.json", content: makeSymbolGraph(
+                    moduleName: "ModuleName",
+                    symbols: [
+                        (containerID, .swift, ["SwiftContainerName"])
+                    ]
+                )),
+                
+                JSONFile(name: "[email protected]", content: makeSymbolGraph(
+                    moduleName: "ExtendingModule",
+                    symbols: [
+                        (memberID, .swift, ["SwiftContainerName", "MemberName"])
+                    ],
+                    relationships: [
+                        .init(source: memberID, target: containerID, kind: .memberOf, targetFallback: nil)
+                    ]
+                )),
+            ])
+        ])
+        
+        let tempURL = try createTempFolder(content: [exampleDocumentation])
+        let (_, _, context) = try loadBundle(from: tempURL)
+        let tree = try XCTUnwrap(context.linkResolver.localResolver?.pathHierarchy)
+        
+        let paths = tree.caseInsensitiveDisambiguatedPaths()
+        XCTAssertEqual(paths[containerID], "/ModuleName/SwiftContainerName")
+        XCTAssertEqual(paths[memberID], "/ModuleName/SwiftContainerName/MemberName")
+    }
+    
     func testOptionalMemberUnderCorrectContainer() throws {
         let containerID = "some-container-symbol-id"
         let otherID = "some-other-symbol-id"