Populate declaration fragments in navigator metadata for external links

Now that the declaration fragments will be the abbreviated declaration fragments from `LinkDestinationSummary`, we can propagate those to the navigator metadata for them to be used to inform the title of the navigator item [1].

Fixes rdar://156488052.

[1]: https://github.com/swiftlang/swift-docc/blob/65aaf926ec079ddbd40f29540d4180a70af99e5e/Sources/SwiftDocC/Indexing/Navigator/RenderNode%2BNavigatorIndex.swift#L140

Author: anferbui

Sources/SwiftDocC/Infrastructure/Link Resolution/LinkResolver+NavigatorIndex.swift

@@ -117,7 +117,8 @@ struct NavigatorExternalRenderNode: NavigatorIndexableRenderNodeRepresentation {
             externalID: renderNode.externalIdentifier.identifier,
             role: renderNode.role,
             symbolKind: renderNode.symbolKind?.identifier,
-            images: renderNode.images
+            images: renderNode.images,
+            fragments: renderNode.fragmentsVariants.value(for: traits)
         )
     }
 }
@@ -130,19 +131,16 @@ struct ExternalRenderNodeMetadataRepresentation: NavigatorIndexableRenderMetadat
     var role: String?
     var symbolKind: String?
     var images: [TopicImage]
+    var fragments: [DeclarationRenderSection.Token]?
 
     // Values that we have insufficient information to derive.
     // These are needed to conform to the navigator indexable metadata protocol.
     //
-    // The fragments that we get as part of the external link are the full declaration fragments.
-    // These are too verbose for the navigator, so instead of using them, we rely on the title, navigator title and symbol kind instead.
-    //
     // The role heading is used to identify Property Lists.
     // The value being missing is used for computing the final navigator title.
     //
     // The platforms are used for generating the availability index,
     // but doesn't affect how the node is rendered in the sidebar.
-    var fragments: [DeclarationRenderSection.Token]? = nil
     var roleHeading: String? = nil
     var platforms: [AvailabilityRenderItem]? = nil
-}
+}

Tests/SwiftDocCTests/Indexing/ExternalRenderNodeTests.swift

@@ -13,7 +13,7 @@ import XCTest
 @_spi(ExternalLinks) @testable import SwiftDocC
 
 class ExternalRenderNodeTests: XCTestCase {
-    func generateExternalResover() -> TestMultiResultExternalReferenceResolver {
+    func generateExternalResolver() -> TestMultiResultExternalReferenceResolver {
         let externalResolver = TestMultiResultExternalReferenceResolver()
         externalResolver.bundleID = "com.test.external"
         externalResolver.entitiesToReturn["/path/to/external/swiftArticle"] = .success(
@@ -37,23 +37,32 @@ class ExternalRenderNodeTests: XCTestCase {
                 referencePath: "/path/to/external/swiftSymbol",
                 title: "SwiftSymbol",
                 kind: .class,
-                language: .swift
+                language: .swift,
+                declarationFragments: .init(declarationFragments: [
+                    .init(kind: .keyword, spelling: "class", preciseIdentifier: nil),
+                    .init(kind: .text, spelling: " ", preciseIdentifier: nil),
+                    .init(kind: .identifier, spelling: "SwiftSymbol", preciseIdentifier: nil)
+                ])
             )
         )
         externalResolver.entitiesToReturn["/path/to/external/objCSymbol"] = .success(
             .init(
                 referencePath: "/path/to/external/objCSymbol",
                 title: "ObjCSymbol",
                 kind: .function,
-                language: .objectiveC
+                language: .objectiveC,
+                declarationFragments: .init(declarationFragments: [
+                    .init(kind: .text, spelling: "- ", preciseIdentifier: nil),
+                    .init(kind: .identifier, spelling: "ObjCSymbol", preciseIdentifier: nil),
+                ])
             )
         )
         return externalResolver
     }
 
     func testExternalRenderNode() throws {
 
-        let externalResolver = generateExternalResover()
+        let externalResolver = generateExternalResolver()
         let (_, bundle, context) = try testBundleAndContext(
             copying: "MixedLanguageFramework",
             externalResolvers: [externalResolver.bundleID: externalResolver]
@@ -146,16 +155,18 @@ class ExternalRenderNodeTests: XCTestCase {
         )
         XCTAssertEqual(swiftNavigatorExternalRenderNode.metadata.title, swiftTitle)
         XCTAssertEqual(swiftNavigatorExternalRenderNode.metadata.navigatorTitle, navigatorTitle)
+        XCTAssertEqual(swiftNavigatorExternalRenderNode.metadata.fragments, fragments)
 
         let objcNavigatorExternalRenderNode = try XCTUnwrap(
             NavigatorExternalRenderNode(renderNode: externalRenderNode, trait: .interfaceLanguage("objc"))
         )
         XCTAssertEqual(objcNavigatorExternalRenderNode.metadata.title, occTitle)
         XCTAssertEqual(objcNavigatorExternalRenderNode.metadata.navigatorTitle, occNavigatorTitle)
+        XCTAssertEqual(objcNavigatorExternalRenderNode.metadata.fragments, occFragments)
     }
 
     func testNavigatorWithExternalNodes() throws {
-        let externalResolver = generateExternalResover()
+        let externalResolver = generateExternalResolver()
         let (_, bundle, context) = try testBundleAndContext(
             copying: "MixedLanguageFramework",
             externalResolvers: [externalResolver.bundleID: externalResolver]
@@ -204,14 +215,14 @@ class ExternalRenderNodeTests: XCTestCase {
         let occExternalNodes = renderIndex.interfaceLanguages["occ"]?.first { $0.path == "/documentation/mixedlanguageframework" }?.children?.filter { $0.path?.contains("/path/to/external") ?? false } ?? []
         XCTAssertEqual(swiftExternalNodes.count, 2)
         XCTAssertEqual(occExternalNodes.count, 2)
-        XCTAssertEqual(swiftExternalNodes.map(\.title), ["SwiftArticle", "SwiftSymbol"])
-        XCTAssertEqual(occExternalNodes.map(\.title), ["ObjCArticle", "ObjCSymbol"])
+        XCTAssertEqual(swiftExternalNodes.map(\.title), ["SwiftArticle", "class SwiftSymbol"])
+        XCTAssertEqual(occExternalNodes.map(\.title), ["ObjCArticle", "- ObjCSymbol"])
         XCTAssert(swiftExternalNodes.allSatisfy(\.isExternal))
         XCTAssert(occExternalNodes.allSatisfy(\.isExternal))
     }
 
     func testNavigatorWithExternalNodesOnlyAddsCuratedNodesToNavigator() throws {
-        let externalResolver = generateExternalResover()
+        let externalResolver = generateExternalResolver()
 
         let (_, bundle, context) = try testBundleAndContext(
             copying: "MixedLanguageFramework",
@@ -265,7 +276,7 @@ class ExternalRenderNodeTests: XCTestCase {
         XCTAssertEqual(swiftExternalNodes.count, 1)
         XCTAssertEqual(occExternalNodes.count, 1)
         XCTAssertEqual(swiftExternalNodes.map(\.title), ["SwiftArticle"])
-        XCTAssertEqual(occExternalNodes.map(\.title), ["ObjCSymbol"])
+        XCTAssertEqual(occExternalNodes.map(\.title), ["- ObjCSymbol"])
         XCTAssert(swiftExternalNodes.allSatisfy(\.isExternal))
         XCTAssert(occExternalNodes.allSatisfy(\.isExternal))
     }