Add default implementations to LanguageService for methods that are not expected to be implemented by all language services

With the introduction of secondary language services, we don’t expect every language service to implement every request anymore. To simplify the addition of language services like `DocumentationLanguageService` add default implementations for methods that satisfy the following criteria:
 - `SourceKitLSPServer` does not expect side effects to happen when they are called
 - The method can throw or there is a reasonable default value
 - It is reasonable to expect that not all language services need to implement it

Author: ahoppen

Sources/ClangLanguageService/ClangLanguageService.swift

@@ -229,7 +229,7 @@ package actor ClangLanguageService: LanguageService, MessageHandler {
         // Theoretically they could have changed and we would need to inform SourceKitLSPServer about them.
         // But since SourceKitLSPServer more or less ignores them right now anyway, this should be fine for now.
         _ = try await self.initialize(initializeRequest)
-        self.clientInitialized(InitializedNotification())
+        await self.clientInitialized(InitializedNotification())
         if let sourceKitLSPServer {
           await sourceKitLSPServer.reopenDocuments(for: self)
         } else {
@@ -309,7 +309,7 @@ package actor ClangLanguageService: LanguageService, MessageHandler {
       logger.fault(
         "Did not receive reply from clangd after \(self.options.semanticServiceRestartTimeoutOrDefault, privacy: .public). Terminating and restarting clangd."
       )
-      self.crash()
+      await self.crash()
       throw error
     }
   }
@@ -318,7 +318,7 @@ package actor ClangLanguageService: LanguageService, MessageHandler {
     return nil
   }
 
-  package func crash() {
+  package func crash() async {
     clangdProcess?.terminateImmediately()
   }
 }
@@ -383,7 +383,7 @@ extension ClangLanguageService {
     return result
   }
 
-  package func clientInitialized(_ initialized: InitializedNotification) {
+  package func clientInitialized(_ initialized: InitializedNotification) async {
     clangd.send(initialized)
   }
 
@@ -430,11 +430,11 @@ extension ClangLanguageService {
     clangd.send(notification)
   }
 
-  package func willSaveDocument(_ notification: WillSaveTextDocumentNotification) {
+  package func willSaveDocument(_ notification: WillSaveTextDocumentNotification) async {
 
   }
 
-  package func didSaveDocument(_ notification: DidSaveTextDocumentNotification) {
+  package func didSaveDocument(_ notification: DidSaveTextDocumentNotification) async {
     clangd.send(notification)
   }
 
@@ -458,7 +458,7 @@ extension ClangLanguageService {
     }
   }
 
-  package func documentDependenciesUpdated(_ uris: Set<DocumentURI>) {
+  package func documentDependenciesUpdated(_ uris: Set<DocumentURI>) async {
     for uri in uris {
       // In order to tell clangd to reload an AST, we send it an empty `didChangeTextDocument`
       // with `forceRebuild` set in case any missing header files have been added.
@@ -510,20 +510,6 @@ extension ClangLanguageService {
     return try await forwardRequestToClangd(req)
   }
 
-  package func symbolGraph(
-    forOnDiskContentsOf symbolDocumentUri: DocumentURI,
-    at location: SymbolLocation
-  ) async throws -> String {
-    throw ResponseError.internalError("Symbol graph is currently not supported for clang files")
-  }
-
-  package func symbolGraph(
-    for snapshot: SourceKitLSP.DocumentSnapshot,
-    at position: LanguageServerProtocol.Position
-  ) async throws -> (symbolGraph: String, usr: String, overrideDocComments: [String]) {
-    throw ResponseError.internalError("Symbol graph is currently not supported for clang files")
-  }
-
   package func documentSymbolHighlight(_ req: DocumentHighlightRequest) async throws -> [DocumentHighlight]? {
     return try await forwardRequestToClangd(req)
   }
@@ -630,15 +616,6 @@ extension ClangLanguageService {
     return try await forwardRequestToClangd(req)
   }
 
-  package func openGeneratedInterface(
-    document: DocumentURI,
-    moduleName: String,
-    groupName: String?,
-    symbolUSR symbol: String?
-  ) async throws -> GeneratedInterfaceDetails? {
-    throw ResponseError.unknown("unsupported method")
-  }
-
   package func indexedRename(_ request: IndexedRenameRequest) async throws -> WorkspaceEdit? {
     return try await forwardRequestToClangd(request)
   }
@@ -649,10 +626,6 @@ extension ClangLanguageService {
     return try await forwardRequestToClangd(req)
   }
 
-  package func getReferenceDocument(_ req: GetReferenceDocumentRequest) async throws -> GetReferenceDocumentResponse {
-    throw ResponseError.unknown("unsupported method")
-  }
-
   package func rename(_ renameRequest: RenameRequest) async throws -> (edits: WorkspaceEdit, usr: String?) {
     async let edits = forwardRequestToClangd(renameRequest)
     let symbolInfoRequest = SymbolInfoRequest(
@@ -663,7 +636,10 @@ extension ClangLanguageService {
     return (try await edits ?? WorkspaceEdit(), symbolDetail?.usr)
   }
 
-  package func syntacticDocumentTests(for uri: DocumentURI, in workspace: Workspace) async -> [AnnotatedTestItem]? {
+  package func syntacticDocumentTests(
+    for uri: DocumentURI,
+    in workspace: Workspace
+  ) async throws -> [AnnotatedTestItem]? {
     return nil
   }
 

Sources/DocumentationLanguageService/DoccDocumentationHandler.swift

@@ -108,7 +108,7 @@ extension DocumentationLanguageService {
         let symbolOccurrence = try await index.primaryDefinitionOrDeclarationOccurrence(
           ofDocCSymbolLink: symbolLink,
           fetchSymbolGraph: { location in
-            guard let symbolWorkspace = try await workspaceForDocument(uri: location.documentUri) else {
+            guard let symbolWorkspace = await sourceKitLSPServer.workspaceForDocument(uri: location.documentUri) else {
               throw ResponseError.internalError("Unable to find language service for \(location.documentUri)")
             }
             let languageService = try await sourceKitLSPServer.primaryLanguageService(
@@ -126,7 +126,7 @@ extension DocumentationLanguageService {
         throw ResponseError.requestFailed(doccDocumentationError: .symbolNotFound(symbolName))
       }
       let symbolDocumentUri = symbolOccurrence.location.documentUri
-      guard let symbolWorkspace = try await workspaceForDocument(uri: symbolDocumentUri) else {
+      guard let symbolWorkspace = await sourceKitLSPServer.workspaceForDocument(uri: symbolDocumentUri) else {
         throw ResponseError.internalError("Unable to find language service for \(symbolDocumentUri)")
       }
       let languageService = try await sourceKitLSPServer.primaryLanguageService(
@@ -182,7 +182,7 @@ extension DocumentationLanguageService {
         catalogURL: catalogURL,
         for: symbolUSR,
         fetchSymbolGraph: { location in
-          guard let symbolWorkspace = try await workspaceForDocument(uri: location.documentUri) else {
+          guard let symbolWorkspace = await sourceKitLSPServer.workspaceForDocument(uri: location.documentUri) else {
             throw ResponseError.internalError("Unable to find language service for \(location.documentUri)")
           }
           let languageService = try await sourceKitLSPServer.primaryLanguageService(

Sources/DocumentationLanguageService/DocumentationLanguageService.swift

@@ -34,8 +34,6 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
     }
   }
 
-  package static var builtInCommands: [String] { [] }
-
   package static var experimentalCapabilities: [String: LSPAny] {
     return [
       DoccDocumentationRequest.method: .dictionary(["version": .int(1)])
@@ -53,13 +51,6 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
     self.documentationManager = DocCDocumentationManager(buildServerManager: workspace.buildServerManager)
   }
 
-  func workspaceForDocument(uri: DocumentURI) async throws -> Workspace? {
-    guard let sourceKitLSPServer else {
-      throw ResponseError.unknown("Connection to the editor closed")
-    }
-    return await sourceKitLSPServer.workspaceForDocument(uri: uri)
-  }
-
   package nonisolated func canHandle(workspace: Workspace, toolchain: Toolchain) -> Bool {
     return true
   }
@@ -72,10 +63,6 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
     )
   }
 
-  package func clientInitialized(_ initialized: InitializedNotification) async {
-    // Nothing to set up
-  }
-
   package func shutdown() async {
     // Nothing to tear down
   }
@@ -109,200 +96,4 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
   ) async {
     // The DocumentationLanguageService does not do anything with document events
   }
-
-  package func willSaveDocument(_ notification: WillSaveTextDocumentNotification) async {
-    // The DocumentationLanguageService does not do anything with document events
-  }
-
-  package func didSaveDocument(_ notification: DidSaveTextDocumentNotification) async {
-    // The DocumentationLanguageService does not do anything with document events
-  }
-
-  package func filesDidChange(_ events: [FileEvent]) async {
-    await documentationManager.filesDidChange(events)
-  }
-
-  package func documentUpdatedBuildSettings(_ uri: DocumentURI) async {
-    // The DocumentationLanguageService does not do anything with document events
-  }
-
-  package func documentDependenciesUpdated(_ uris: Set<DocumentURI>) async {
-    // The DocumentationLanguageService does not do anything with document events
-  }
-
-  package func completion(_ req: CompletionRequest) async throws -> CompletionList {
-    CompletionList(isIncomplete: false, items: [])
-  }
-
-  package func completionItemResolve(_ req: CompletionItemResolveRequest) async throws -> CompletionItem {
-    return req.item
-  }
-
-  package func hover(_ req: HoverRequest) async throws -> HoverResponse? {
-    nil
-  }
-
-  package func symbolInfo(_ request: SymbolInfoRequest) async throws -> [SymbolDetails] {
-    []
-  }
-
-  package func symbolGraph(
-    forOnDiskContentsOf symbolDocumentUri: DocumentURI,
-    at location: SymbolLocation
-  ) async throws -> String {
-    throw ResponseError.internalError("Not applicable")
-  }
-
-  package func symbolGraph(
-    for snapshot: SourceKitLSP.DocumentSnapshot,
-    at position: LanguageServerProtocol.Position
-  ) async throws -> (symbolGraph: String, usr: String, overrideDocComments: [String]) {
-    throw ResponseError.internalError("Not applicable")
-  }
-
-  package func openGeneratedInterface(
-    document: DocumentURI,
-    moduleName: String,
-    groupName: String?,
-    symbolUSR symbol: String?
-  ) async throws -> GeneratedInterfaceDetails? {
-    nil
-  }
-
-  package func definition(_ request: DefinitionRequest) async throws -> LocationsOrLocationLinksResponse? {
-    nil
-  }
-
-  package func declaration(_ request: DeclarationRequest) async throws -> LocationsOrLocationLinksResponse? {
-    nil
-  }
-
-  package func documentSymbolHighlight(_ req: DocumentHighlightRequest) async throws -> [DocumentHighlight]? {
-    nil
-  }
-
-  package func foldingRange(_ req: FoldingRangeRequest) async throws -> [FoldingRange]? {
-    nil
-  }
-
-  package func documentSymbol(_ req: DocumentSymbolRequest) async throws -> DocumentSymbolResponse? {
-    nil
-  }
-
-  package func documentColor(_ req: DocumentColorRequest) async throws -> [ColorInformation] {
-    []
-  }
-
-  package func documentSemanticTokens(
-    _ req: DocumentSemanticTokensRequest
-  ) async throws -> DocumentSemanticTokensResponse? {
-    nil
-  }
-
-  package func documentSemanticTokensDelta(
-    _ req: DocumentSemanticTokensDeltaRequest
-  ) async throws -> DocumentSemanticTokensDeltaResponse? {
-    nil
-  }
-
-  package func documentSemanticTokensRange(
-    _ req: DocumentSemanticTokensRangeRequest
-  ) async throws -> DocumentSemanticTokensResponse? {
-    nil
-  }
-
-  package func colorPresentation(_ req: ColorPresentationRequest) async throws -> [ColorPresentation] {
-    []
-  }
-
-  package func codeAction(_ req: CodeActionRequest) async throws -> CodeActionRequestResponse? {
-    nil
-  }
-
-  package func inlayHint(_ req: InlayHintRequest) async throws -> [InlayHint] {
-    []
-  }
-
-  package func codeLens(_ req: CodeLensRequest) async throws -> [CodeLens] {
-    []
-  }
-
-  package func documentDiagnostic(_ req: DocumentDiagnosticsRequest) async throws -> DocumentDiagnosticReport {
-    .full(RelatedFullDocumentDiagnosticReport(items: []))
-  }
-
-  package func documentFormatting(_ req: DocumentFormattingRequest) async throws -> [TextEdit]? {
-    nil
-  }
-
-  package func documentRangeFormatting(
-    _ req: LanguageServerProtocol.DocumentRangeFormattingRequest
-  ) async throws -> [LanguageServerProtocol.TextEdit]? {
-    return nil
-  }
-
-  package func documentOnTypeFormatting(_ req: DocumentOnTypeFormattingRequest) async throws -> [TextEdit]? {
-    return nil
-  }
-
-  package func rename(_ request: RenameRequest) async throws -> (edits: WorkspaceEdit, usr: String?) {
-    (edits: WorkspaceEdit(), usr: nil)
-  }
-
-  package func editsToRename(
-    locations renameLocations: [RenameLocation],
-    in snapshot: DocumentSnapshot,
-    oldName: CrossLanguageName,
-    newName: CrossLanguageName
-  ) async throws -> [TextEdit] {
-    []
-  }
-
-  package func prepareRename(
-    _ request: PrepareRenameRequest
-  ) async throws -> (prepareRename: PrepareRenameResponse, usr: String?)? {
-    nil
-  }
-
-  package func indexedRename(_ request: IndexedRenameRequest) async throws -> WorkspaceEdit? {
-    nil
-  }
-
-  package func editsToRenameParametersInFunctionBody(
-    snapshot: DocumentSnapshot,
-    renameLocation: RenameLocation,
-    newName: CrossLanguageName
-  ) async -> [TextEdit] {
-    []
-  }
-
-  package func executeCommand(_ req: ExecuteCommandRequest) async throws -> LSPAny? {
-    nil
-  }
-
-  package func getReferenceDocument(_ req: GetReferenceDocumentRequest) async throws -> GetReferenceDocumentResponse {
-    GetReferenceDocumentResponse(content: "")
-  }
-
-  package func syntacticDocumentTests(
-    for uri: DocumentURI,
-    in workspace: Workspace
-  ) async throws -> [AnnotatedTestItem]? {
-    nil
-  }
-
-  package static func syntacticTestItems(in uri: DocumentURI) async -> [AnnotatedTestItem] {
-    return []
-  }
-
-  package func canonicalDeclarationPosition(
-    of position: Position,
-    in uri: DocumentURI
-  ) async -> Position? {
-    nil
-  }
-
-  package func crash() async {
-    // There's no way to crash the DocumentationLanguageService
-  }
 }