[Concurrency] add deprecated shim for Task.withGroup

Author: ktoso

stdlib/public/Concurrency/Task.swift

@@ -368,8 +368,8 @@ extension Task {
   @available(*, deprecated, message: "`Task.runDetached` was replaced by `detach` and will be removed shortly.")
   public func runDetached<T>(
     priority: Task.Priority = .unspecified,
-    operation: __owned @Sendable @escaping () async -> T
-  ) -> Task.Handle<T, Never> {
+    operation: __owned @Sendable @escaping () async throws -> T
+  ) -> Task.Handle<T, Error> {
     detach(priority: priority, operation: operation)
   }
 
@@ -519,6 +519,22 @@ extension Task {
 
 // ==== UnsafeCurrentTask ------------------------------------------------------
 
+@available(macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, *)
+extension Task {
+
+  @available(*, deprecated, message: "`Task.unsafeCurrent` was replaced by `withUnsafeCurrentTask { task in ... }`, and will be removed soon.")
+  public static var unsafeCurrent: UnsafeCurrentTask? {
+    guard let _task = _getCurrentAsyncTask() else {
+      return nil
+    }
+    // FIXME: This retain seems pretty wrong, however if we don't we WILL crash
+    //        with "destroying a task that never completed" in the task's destroy.
+    //        How do we solve this properly?
+    _swiftRetain(_task)
+    return UnsafeCurrentTask(_task)
+  }
+}
+
 /// Calls the given closure with the with the "current" task in which this
 /// function was invoked.
 ///

stdlib/public/Concurrency/TaskGroup.swift

@@ -15,6 +15,24 @@ import Swift
 
 // ==== TaskGroup --------------------------------------------------------------
 
+@available(macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, *)
+extension Task {
+  @available(*, deprecated, message: "`Task.Group` was replaced by `ThrowingTaskGroup` and `TaskGroup` and will be removed shortly.")
+  public typealias Group<TaskResult: Sendable> = ThrowingTaskGroup<TaskResult, Error>
+
+  @available(*, deprecated, message: "`Task.withGroup` was replaced by `withThrowingTaskGroup` and `withTaskGroup` and will be removed shortly.")
+  public static func withGroup<TaskResult, BodyResult>(
+      resultType: TaskResult.Type,
+      returning returnType: BodyResult.Type = BodyResult.self,
+      body: (inout Task.Group<TaskResult>) async throws -> BodyResult
+  ) async rethrows -> BodyResult {
+    try await withThrowingTaskGroup(of: resultType) { group in
+      try await body(&group)
+    }
+  }
+}
+
+
 /// Starts a new task group which provides a scope in which a dynamic number of
 /// tasks may be spawned.
 ///
@@ -206,8 +224,19 @@ public struct TaskGroup<ChildTaskResult: Sendable> {
     self._task = task
     self._group = group
   }
-  
-  /// Add a child task to the group.
+
+  @available(*, deprecated, message: "`Task.Group.add` has been replaced by `TaskGroup.spawn` or `TaskGroup.spawnUnlessCancelled` and will be removed shortly.")
+  public mutating func add(
+      priority: Task.Priority = .unspecified,
+      operation: __owned @Sendable @escaping () async -> ChildTaskResult
+  ) async -> Bool {
+    return try await self.spawnUnlessCancelled(priority: priority) {
+      try! await operation()
+    }
+  }
+
+
+/// Add a child task to the group.
   ///
   /// ### Error handling
   /// Operations are allowed to `throw`, in which case the `try await next()`
@@ -446,6 +475,16 @@ public struct ThrowingTaskGroup<ChildTaskResult: Sendable, Failure: Error> {
     self._group = group
   }
 
+  @available(*, deprecated, message: "`Task.Group.add` has been replaced by `(Throwing)TaskGroup.spawn` or `(Throwing)TaskGroup.spawnUnlessCancelled` and will be removed shortly.")
+  public mutating func add(
+    priority: Task.Priority = .unspecified,
+    operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
+  ) async -> Bool {
+    return try await self.spawnUnlessCancelled(priority: priority) {
+      try await operation()
+    }
+  }
+
   /// Spawn, unconditionally, a child task in the group.
   ///
   /// ### Error handling