Allow injection of build systems into SourceKitLSP

Sources/BuildSystemIntegration/BuildSystemManager.swift

@@ -145,7 +145,7 @@ private extension BuildSystemSpec {
   private static func createBuiltInBuildSystemAdapter(
     projectRoot: URL,
     messagesToSourceKitLSPHandler: any MessageHandler,
-    buildSystemTestHooks: BuildSystemTestHooks,
+    buildSystemHooks: BuildSystemHooks,
     _ createBuildSystem: @Sendable (_ connectionToSourceKitLSP: any Connection) async throws -> BuiltInBuildSystem?
   ) async -> BuildSystemAdapter? {
     let connectionToSourceKitLSP = LocalConnection(
@@ -164,7 +164,7 @@ private extension BuildSystemSpec {
     let buildSystemAdapter = BuiltInBuildSystemAdapter(
       underlyingBuildSystem: buildSystem,
       connectionToSourceKitLSP: connectionToSourceKitLSP,
-      buildSystemTestHooks: buildSystemTestHooks
+      buildSystemHooks: buildSystemHooks
     )
     let connectionToBuildSystem = LocalConnection(
       receiverName: "\(type(of: buildSystem)) for \(projectRoot.lastPathComponent)"
@@ -178,7 +178,7 @@ private extension BuildSystemSpec {
   func createBuildSystemAdapter(
     toolchainRegistry: ToolchainRegistry,
     options: SourceKitLSPOptions,
-    buildSystemTestHooks testHooks: BuildSystemTestHooks,
+    buildSystemHooks: BuildSystemHooks,
     messagesToSourceKitLSPHandler: any MessageHandler
   ) async -> BuildSystemAdapter? {
     switch self.kind {
@@ -199,7 +199,7 @@ private extension BuildSystemSpec {
       return await Self.createBuiltInBuildSystemAdapter(
         projectRoot: projectRoot,
         messagesToSourceKitLSPHandler: messagesToSourceKitLSPHandler,
-        buildSystemTestHooks: testHooks
+        buildSystemHooks: buildSystemHooks
       ) { connectionToSourceKitLSP in
         CompilationDatabaseBuildSystem(
           projectRoot: projectRoot,
@@ -214,26 +214,26 @@ private extension BuildSystemSpec {
       return await Self.createBuiltInBuildSystemAdapter(
         projectRoot: projectRoot,
         messagesToSourceKitLSPHandler: messagesToSourceKitLSPHandler,
-        buildSystemTestHooks: testHooks
+        buildSystemHooks: buildSystemHooks
       ) { connectionToSourceKitLSP in
         try await SwiftPMBuildSystem(
           projectRoot: projectRoot,
           toolchainRegistry: toolchainRegistry,
           options: options,
           connectionToSourceKitLSP: connectionToSourceKitLSP,
-          testHooks: testHooks.swiftPMTestHooks
+          testHooks: buildSystemHooks.swiftPMTestHooks
         )
       }
       #else
       return nil
       #endif
-    case .testBuildSystem:
+    case .injected(let injector):
       return await Self.createBuiltInBuildSystemAdapter(
         projectRoot: projectRoot,
         messagesToSourceKitLSPHandler: messagesToSourceKitLSPHandler,
-        buildSystemTestHooks: testHooks
+        buildSystemHooks: buildSystemHooks
       ) { connectionToSourceKitLSP in
-        TestBuildSystem(projectRoot: projectRoot, connectionToSourceKitLSP: connectionToSourceKitLSP)
+        await injector.createBuildSystem(projectRoot: projectRoot, connectionToSourceKitLSP: connectionToSourceKitLSP)
       }
     }
   }
@@ -275,19 +275,6 @@ package actor BuildSystemManager: QueueBasedMessageHandler {
     }
   }
 
-  /// If the underlying build system is a `TestBuildSystem`, return it. Otherwise, `nil`
-  ///
-  /// - Important: For testing purposes only.
-  package var testBuildSystem: TestBuildSystem? {
-    get async {
-      switch buildSystemAdapter {
-      case .builtIn(let builtInBuildSystemAdapter, _): return await builtInBuildSystemAdapter.testBuildSystem
-      case .external: return nil
-      case nil: return nil
-      }
-    }
-  }
-
   /// Provider of file to main file mappings.
   private var mainFilesProvider: MainFilesProvider?
 
@@ -367,7 +354,7 @@ package actor BuildSystemManager: QueueBasedMessageHandler {
     toolchainRegistry: ToolchainRegistry,
     options: SourceKitLSPOptions,
     connectionToClient: BuildSystemManagerConnectionToClient,
-    buildSystemTestHooks: BuildSystemTestHooks
+    buildSystemHooks: BuildSystemHooks
   ) async {
     self.toolchainRegistry = toolchainRegistry
     self.options = options
@@ -376,7 +363,7 @@ package actor BuildSystemManager: QueueBasedMessageHandler {
     self.buildSystemAdapter = await buildSystemSpec?.createBuildSystemAdapter(
       toolchainRegistry: toolchainRegistry,
       options: options,
-      buildSystemTestHooks: buildSystemTestHooks,
+      buildSystemHooks: buildSystemHooks,
       messagesToSourceKitLSPHandler: WeakMessageHandler(self)
     )
 
@@ -432,7 +419,7 @@ package actor BuildSystemManager: QueueBasedMessageHandler {
         let adapter = BuiltInBuildSystemAdapter(
           underlyingBuildSystem: legacyBuildServer,
           connectionToSourceKitLSP: legacyBuildServer.connectionToSourceKitLSP,
-          buildSystemTestHooks: buildSystemTestHooks
+          buildSystemHooks: buildSystemHooks
         )
         let connectionToBuildSystem = LocalConnection(receiverName: "Legacy BSP server")
         connectionToBuildSystem.start(handler: adapter)

Sources/BuildSystemIntegration/BuildSystemTestHooks.swift

@@ -12,8 +12,10 @@
 
 #if compiler(>=6)
 package import LanguageServerProtocol
+package import Foundation
 #else
 import LanguageServerProtocol
+import Foundation
 #endif
 
 package struct SwiftPMTestHooks: Sendable {
@@ -29,19 +31,29 @@ package struct SwiftPMTestHooks: Sendable {
   }
 }
 
-package struct BuildSystemTestHooks: Sendable {
+/// When running SourceKit-LSP in-process, allows the creator of `SourceKitLSPServer` to create the build system instead
+/// of SourceKit-LSP creating build systems as needed.
+package protocol BuildSystemInjector: Sendable {
+  func createBuildSystem(projectRoot: URL, connectionToSourceKitLSP: any Connection) async -> BuiltInBuildSystem
+}
+
+package struct BuildSystemHooks: Sendable {
   package var swiftPMTestHooks: SwiftPMTestHooks
 
   /// A hook that will be executed before a request is handled by a `BuiltInBuildSystem`.
   ///
   /// This allows requests to be artificially delayed.
-  package var handleRequest: (@Sendable (any RequestType) async -> Void)?
+  package var preHandleRequest: (@Sendable (any RequestType) async -> Void)?
+
+  package var buildSystemInjector: BuildSystemInjector?
 
   package init(
     swiftPMTestHooks: SwiftPMTestHooks = SwiftPMTestHooks(),
-    handleRequest: (@Sendable (any RequestType) async -> Void)? = nil
+    preHandleRequest: (@Sendable (any RequestType) async -> Void)? = nil,
+    buildSystemInjector: BuildSystemInjector? = nil
   ) {
     self.swiftPMTestHooks = swiftPMTestHooks
-    self.handleRequest = handleRequest
+    self.preHandleRequest = preHandleRequest
+    self.buildSystemInjector = buildSystemInjector
   }
 }

Sources/BuildSystemIntegration/BuiltInBuildSystemAdapter.swift

@@ -30,7 +30,7 @@ package struct BuildSystemSpec {
     case buildServer
     case compilationDatabase
     case swiftPM
-    case testBuildSystem
+    case injected(BuildSystemInjector)
   }
 
   package var kind: Kind
@@ -59,25 +59,18 @@ actor BuiltInBuildSystemAdapter: QueueBasedMessageHandler {
   /// The connection with which messages are sent to `BuildSystemManager`.
   private let connectionToSourceKitLSP: LocalConnection
 
-  private let buildSystemTestHooks: BuildSystemTestHooks
-
-  /// If the underlying build system is a `TestBuildSystem`, return it. Otherwise, `nil`
-  ///
-  /// - Important: For testing purposes only.
-  var testBuildSystem: TestBuildSystem? {
-    return underlyingBuildSystem as? TestBuildSystem
-  }
+  private let buildSystemHooks: BuildSystemHooks
 
   /// Create a `BuiltInBuildSystemAdapter` form an existing `BuiltInBuildSystem` and connection to communicate messages
   /// from the build system to SourceKit-LSP.
   init(
     underlyingBuildSystem: BuiltInBuildSystem,
     connectionToSourceKitLSP: LocalConnection,
-    buildSystemTestHooks: BuildSystemTestHooks
+    buildSystemHooks: BuildSystemHooks
   ) {
     self.underlyingBuildSystem = underlyingBuildSystem
     self.connectionToSourceKitLSP = connectionToSourceKitLSP
-    self.buildSystemTestHooks = buildSystemTestHooks
+    self.buildSystemHooks = buildSystemHooks
   }
 
   deinit {
@@ -124,7 +117,7 @@ actor BuiltInBuildSystemAdapter: QueueBasedMessageHandler {
     reply: @Sendable @escaping (LSPResult<Request.Response>) -> Void
   ) async {
     let request = RequestAndReply(request, reply: reply)
-    await buildSystemTestHooks.handleRequest?(request.params)
+    await buildSystemHooks.preHandleRequest?(request.params)
     switch request {
     case let request as RequestAndReply<BuildShutdownRequest>:
       await request.reply { VoidResponse() }

Sources/BuildSystemIntegration/DetermineBuildSystem.swift

@@ -36,8 +36,13 @@ import struct TSCBasic.AbsolutePath
 /// Returns `nil` if no build system can handle this workspace folder.
 package func determineBuildSystem(
   forWorkspaceFolder workspaceFolder: DocumentURI,
-  options: SourceKitLSPOptions
+  options: SourceKitLSPOptions,
+  hooks: BuildSystemHooks
 ) -> BuildSystemSpec? {
+  if let workspaceURL = workspaceFolder.fileURL, let buildSystemInjector = hooks.buildSystemInjector {
+    return BuildSystemSpec(kind: .injected(buildSystemInjector), projectRoot: workspaceURL)
+  }
+
   var buildSystemPreference: [WorkspaceType] = [
     .buildServer, .swiftPM, .compilationDatabase,
   ]

Sources/InProcessClient/InProcessSourceKitLSPClient.swift

@@ -10,30 +10,22 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if compiler(>=6)
 import BuildSystemIntegration
 public import Foundation
 public import LanguageServerProtocol
 import LanguageServerProtocolExtensions
-package import SKOptions
-import SourceKitLSP
 import SwiftExtensions
-import ToolchainRegistry
 import TSCExtensions
+import ToolchainRegistry
 
 import struct TSCBasic.AbsolutePath
+
+#if compiler(>=6)
+package import SKOptions
+package import SourceKitLSP
 #else
-import BuildSystemIntegration
-import Foundation
-import LanguageServerProtocol
-import LanguageServerProtocolExtensions
 import SKOptions
 import SourceKitLSP
-import SwiftExtensions
-import ToolchainRegistry
-import TSCExtensions
-
-import struct TSCBasic.AbsolutePath
 #endif
 
 /// Launches a `SourceKitLSPServer` in-process and allows sending messages to it.
@@ -63,6 +55,7 @@ public final class InProcessSourceKitLSPClient: Sendable {
   package init(
     toolchainPath: URL?,
     options: SourceKitLSPOptions = SourceKitLSPOptions(),
+    hooks: Hooks = Hooks(),
     capabilities: ClientCapabilities = ClientCapabilities(),
     workspaceFolders: [WorkspaceFolder],
     messageHandler: any MessageHandler
@@ -72,7 +65,7 @@ public final class InProcessSourceKitLSPClient: Sendable {
       client: serverToClientConnection,
       toolchainRegistry: ToolchainRegistry(installPath: toolchainPath),
       options: options,
-      testHooks: TestHooks(),
+      hooks: hooks,
       onExit: {
         serverToClientConnection.close()
       }

Sources/SKTestSupport/MultiFileTestProject.swift

@@ -133,7 +133,7 @@ package class MultiFileTestProject {
     initializationOptions: LSPAny? = nil,
     capabilities: ClientCapabilities = ClientCapabilities(),
     options: SourceKitLSPOptions = .testDefault(),
-    testHooks: TestHooks = TestHooks(),
+    hooks: Hooks = Hooks(),
     enableBackgroundIndexing: Bool = false,
     usePullDiagnostics: Bool = true,
     preInitialization: ((TestSourceKitLSPClient) -> Void)? = nil,
@@ -145,7 +145,7 @@ package class MultiFileTestProject {
 
     self.testClient = try await TestSourceKitLSPClient(
       options: options,
-      testHooks: testHooks,
+      hooks: hooks,
       initializationOptions: initializationOptions,
       capabilities: capabilities,
       usePullDiagnostics: usePullDiagnostics,

Sources/SKTestSupport/SwiftPMTestProject.swift

@@ -197,7 +197,7 @@ package class SwiftPMTestProject: MultiFileTestProject {
     initializationOptions: LSPAny? = nil,
     capabilities: ClientCapabilities = ClientCapabilities(),
     options: SourceKitLSPOptions = .testDefault(),
-    testHooks: TestHooks = TestHooks(),
+    hooks: Hooks = Hooks(),
     enableBackgroundIndexing: Bool = false,
     usePullDiagnostics: Bool = true,
     pollIndex: Bool = true,
@@ -238,7 +238,7 @@ package class SwiftPMTestProject: MultiFileTestProject {
       initializationOptions: initializationOptions,
       capabilities: capabilities,
       options: options,
-      testHooks: testHooks,
+      hooks: hooks,
       enableBackgroundIndexing: enableBackgroundIndexing,
       usePullDiagnostics: usePullDiagnostics,
       preInitialization: preInitialization,

Sources/SKTestSupport/TestSourceKitLSPClient.swift

@@ -146,7 +146,7 @@ package final class TestSourceKitLSPClient: MessageHandler, Sendable {
   ///     needed.
   package init(
     options: SourceKitLSPOptions = .testDefault(),
-    testHooks: TestHooks = TestHooks(),
+    hooks: Hooks = Hooks(),
     initialize: Bool = true,
     initializationOptions: LSPAny? = nil,
     capabilities: ClientCapabilities = ClientCapabilities(),
@@ -177,7 +177,7 @@ package final class TestSourceKitLSPClient: MessageHandler, Sendable {
       client: serverToClientConnection,
       toolchainRegistry: ToolchainRegistry.forTesting,
       options: options,
-      testHooks: testHooks,
+      hooks: hooks,
       onExit: {
         serverToClientConnection.close()
       }

Sources/SourceKitLSP/Clang/ClangLanguageService.swift

@@ -113,7 +113,7 @@ actor ClangLanguageService: LanguageService, MessageHandler {
     sourceKitLSPServer: SourceKitLSPServer,
     toolchain: Toolchain,
     options: SourceKitLSPOptions,
-    testHooks: TestHooks,
+    hooks: Hooks,
     workspace: Workspace
   ) async throws {
     guard let clangdPath = toolchain.clangd else {

Sources/SourceKitLSP/Documentation/DocumentationLanguageService.swift

@@ -29,7 +29,7 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
     sourceKitLSPServer: SourceKitLSPServer,
     toolchain: Toolchain,
     options: SourceKitLSPOptions,
-    testHooks: TestHooks,
+    hooks: Hooks,
     workspace: Workspace
   ) async throws {}
 

Sources/SourceKitLSP/LanguageService.swift

@@ -109,7 +109,7 @@ package protocol LanguageService: AnyObject, Sendable {
     sourceKitLSPServer: SourceKitLSPServer,
     toolchain: Toolchain,
     options: SourceKitLSPOptions,
-    testHooks: TestHooks,
+    hooks: Hooks,
     workspace: Workspace
   ) async throws