[ConvertService] Set metadata.remoteSource

When using ConvertService to generate documentation, makes DocC set the
symbol's declaration file path and line to the `metadata.remoteSource`
property.

rdar://104049149

Author: franklinsch

Sources/SwiftDocC/Model/Rendering/RenderNodeTranslator.swift

@@ -1297,12 +1297,22 @@ public struct RenderNodeTranslator: SemanticVisitor {
             )
         )
 
+        var sourceRepository = sourceRepository
+        
         if shouldEmitSymbolSourceFileURIs {
             node.metadata.sourceFileURIVariants = VariantCollection<String?>(
                 from: symbol.locationVariants
             ) { _, location in
                 location.uri
             } ?? .init(defaultValue: nil)
+            
+            // If a source repository is not set, set the device's
+            // filesystem as the source repository. This causes
+            // the `metadata.remoteSource` property to link to the
+            // file's location on disk.
+            if sourceRepository == nil {
+                sourceRepository = .localFilesystem()
+            }
         }
 
         if let sourceRepository = sourceRepository {

Sources/SwiftDocC/SourceRepository/SourceRepository.swift

@@ -89,4 +89,16 @@ public extension SourceRepository {
             formatLineNumber: { line in "lines-\(line)" }
         )
     }
+    
+    /// Creates a source repository hosted by the device's filesystem.
+    ///
+    /// Use this source repository to format `file://` links to files on the
+    /// device where documentation is being presented.
+    static func localFilesystem() -> SourceRepository {
+        SourceRepository(
+            checkoutPath: "",
+            sourceServiceBaseURL: URL(fileURLWithPath: "/"),
+            formatLineNumber: { line in "L\(line)" }
+        )
+    }
 }

Tests/SwiftDocCTests/DocumentationService/ConvertService/ConvertServiceTests.swift

@@ -152,6 +152,47 @@ class ConvertServiceTests: XCTestCase {
         }
     }
 
+    func testIncludesRemoteSourceInformationForSymbol() throws {
+        let symbolGraphFile = Bundle.module.url(
+            forResource: "mykit-one-symbol",
+            withExtension: "symbols.json",
+            subdirectory: "Test Resources"
+        )!
+        
+        let symbolGraph = try Data(contentsOf: symbolGraphFile)
+        
+        let request = ConvertRequest(
+            bundleInfo: testBundleInfo,
+            externalIDsToConvert: ["s:5MyKit0A5ClassC10myFunctionyyF"],
+            documentPathsToConvert: [],
+            symbolGraphs: [symbolGraph],
+            markupFiles: [],
+            miscResourceURLs: []
+        )
+        
+        try processAndAssert(request: request) { message in
+            XCTAssertEqual(message.type, "convert-response")
+            XCTAssertEqual(message.identifier, "test-identifier-response")
+            
+            let renderNodes = try JSONDecoder().decode(
+                ConvertResponse.self, from: XCTUnwrap(message.payload)).renderNodes
+            
+            XCTAssertEqual(renderNodes.count, 1)
+            let data = try XCTUnwrap(renderNodes.first)
+            let renderNode = try JSONDecoder().decode(RenderNode.self, from: data)
+            
+            XCTAssertEqual(
+                renderNode.metadata.remoteSource?.fileName,
+                "test.swift"
+            )
+            
+            XCTAssertEqual(
+                renderNode.metadata.remoteSource?.url.absoluteString,
+                "file:///private/tmp/test.swift#L2"
+            )
+        }
+    }
+    
     func testConvertSinglePageWithUnrelatedDocumentationExtension() throws {
         let symbolGraphFile = Bundle.module.url(
             forResource: "mykit-one-symbol",

Tests/SwiftDocCTests/SourceRepository/SourceRepositoryTests.swift

@@ -83,4 +83,12 @@ class SourceRepositoryTests: XCTestCase {
             URL(string: "https://example.com/source/file#lines-5")!
         )
     }
+    
+    func testLocalFileSystemFormatting() {
+        XCTAssertEqual(
+            SourceRepository.localFilesystem()
+                .format(sourceFileURL: URL(string: "file:///path/to/file")!, lineNumber: 5),
+            URL(string: "file:///path/to/file#L5")!
+        )
+    }
 }