[Concurrency] TaskGroup with task names

Author: ktoso

stdlib/public/Concurrency/Task.swift

@@ -704,6 +704,7 @@ extension Task where Failure == Never {
   @available(SwiftStdlib 6.2, *)
   public init(
     name: String? = nil,
+    // TaskExecutor is unavailable in embedded
     priority: TaskPriority? = nil,
     @_inheritActorContext @_implicitSelfCapture operation: sending @escaping () async -> Success
   ) {
@@ -762,7 +763,8 @@ extension Task where Failure == Never {
     // Create the asynchronous task.
     let builtinSerialExecutor =
       Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
-    let task: Builtin.NativeObject
+
+    var task: Builtin.NativeObject?
     #if $BuiltinCreateAsyncTaskName
     if var name {
       task =
@@ -773,21 +775,17 @@ extension Task where Failure == Never {
             taskName: nameBytes.baseAddress?._rawValue,
             operation: operation).0
       }
-    } else {
-      task = Builtin.createTask(
-        flags: flags,
-        initialSerialExecutor: builtinSerialExecutor,
-        operation: operation).0
     }
-    #else
-    task = Builtin.createTask(
+    #endif
+    if task == nil {
+      // either no task name was set, or names are unsupported
+      task = Builtin.createTask(
       flags: flags,
-      // unsupported names, so we drop it.
       initialSerialExecutor: builtinSerialExecutor,
       operation: operation).0
-    #endif
+    }
 
-    self._task = task
+    self._task = task!
   }
 #endif
 }

stdlib/public/Concurrency/TaskGroup.swift

@@ -362,12 +362,72 @@ public struct TaskGroup<ChildTaskResult: Sendable> {
     // Create the task in this group.
     let builtinSerialExecutor =
       Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
+
     _ = Builtin.createTask(flags: flags,
                            initialSerialExecutor: builtinSerialExecutor,
                            taskGroup: _group,
                            operation: operation)
   }
 
+  /// Adds a child task to the group.
+  ///
+  /// - Parameters:
+  ///   - name: Human readable name of this task.
+  ///   - priority: The priority of the operation task.
+  ///     Omit this parameter or pass `.unspecified`
+  ///     to set the child task's priority to the priority of the group.
+  ///   - operation: The operation to execute as part of the task group.
+  @_alwaysEmitIntoClient
+  public mutating func addTask(
+    name: String? = nil,
+    priority: TaskPriority? = nil,
+    operation: sending @escaping @isolated(any) () async -> ChildTaskResult
+  ) {
+    #if SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY
+    let enqueueJob = false
+    #else
+    let enqueueJob = true
+    #endif
+
+    let flags = taskCreateFlags(
+      priority: priority, isChildTask: true, copyTaskLocals: false,
+      inheritContext: false, enqueueJob: enqueueJob,
+      addPendingGroupTaskUnconditionally: true,
+      isDiscardingTask: false
+    )
+
+    // Create the task in this group.
+    let builtinSerialExecutor =
+      Builtin.extractFunctionIsolation(operation)?.unownedExecutor.executor
+
+    var task: Builtin.NativeObject?
+    #if $BuiltinCreateAsyncTaskName
+    if var name {
+      task =
+        name.withUTF8 { nameBytes in
+          Builtin.createTask(
+            flags: flags,
+            initialSerialExecutor: builtinSerialExecutor,
+            taskGroup: _group,
+            taskName: nameBytes.baseAddress?._rawValue,
+            operation: operation).0
+        }
+    }
+    #endif
+
+    if task == nil {
+      // either no task name was set, or names are unsupported
+      task = Builtin.createTask(
+        flags: flags,
+        // unsupported names, so we drop it.
+        initialSerialExecutor: builtinSerialExecutor,
+        operation: operation).0
+    }
+
+    // task was enqueued to the group, no need to store the 'task' ref itself
+    assert(task != nil, "Expected task to be created!")
+  }
+
   /// Adds a child task to the group, unless the group has been canceled.
   ///
   /// - Parameters:

test/Concurrency/Runtime/async_task_naming.swift

@@ -22,9 +22,17 @@ func test() async {
 //    return 12
 //  }.value
 
-//  _ = await withTaskGroup(of: Int.self) { g in
-//    g.addTask(name: "Caplin the TaskGroup Task") {
-//      // CHECK: Task.name = Caplin the TaskGroup Task
+  _ = await withTaskGroup(of: Int.self) { g in
+    g.addTask(name: "Caplin the TaskGroup Task") {
+      // CHECK: Task.name = Caplin the TaskGroup Task
+      print("Task.name = \(Task.name ?? "NONE")")
+      return 12
+    }
+  }
+
+//  _ = await withThrowingTaskGroup(of: Int.self) { g in
+//    g.addTask(name: "Caplin the ThrowingTaskGroup Task") {
+//      // CHECK: Task.name = Caplin the ThrowingTaskGroup Task
 //      print("Task.name = \(Task.name ?? "NONE")")
 //      return 12
 //    }