Merge pull request swiftlang#75250 from DougGregor/unsafe-inherit-executor-the-rest-6.0

[6.0] Extend _unsafeInheritExecutor_ to remaining @_unsafeInheritExecutor APIs

Author: DougGregor

lib/Sema/TypeCheckAttr.cpp

@@ -7213,7 +7213,10 @@ void AttributeChecker::visitUnsafeInheritExecutorAttr(
   auto fn = cast<FuncDecl>(D);
   if (!fn->isAsyncContext()) {
     diagnose(attr->getLocation(), diag::inherits_executor_without_async);
-  } else {
+  } else if (fn->getBaseName().isSpecial() ||
+             !fn->getParentModule()->getName().str().equals("_Concurrency") ||
+             !fn->getBaseIdentifier().str()
+                .startswith("_unsafeInheritExecutor_")) {
     bool inConcurrencyModule = D->getDeclContext()->getParentModule()->getName()
         .str().equals("_Concurrency");
     auto diag = fn->diagnose(diag::unsafe_inherits_executor_deprecated);

lib/Sema/TypeCheckConcurrency.cpp

@@ -2108,7 +2108,8 @@ void swift::introduceUnsafeInheritExecutorReplacements(
 
   auto isReplaceable = [&](ValueDecl *decl) {
     return isa<FuncDecl>(decl) && inConcurrencyModule(decl->getDeclContext()) &&
-        decl->getDeclContext()->isModuleScopeContext();
+        decl->getDeclContext()->isModuleScopeContext() &&
+        cast<FuncDecl>(decl)->hasAsync();
   };
 
   // Make sure at least some of the entries are functions in the _Concurrency
@@ -2163,7 +2164,8 @@ void swift::introduceUnsafeInheritExecutorReplacements(
     return;
 
   auto isReplaceable = [&](ValueDecl *decl) {
-    return isa<FuncDecl>(decl) && inConcurrencyModule(decl->getDeclContext());
+    return isa<FuncDecl>(decl) && inConcurrencyModule(decl->getDeclContext()) &&
+      cast<FuncDecl>(decl)->hasAsync();
   };
 
   // Make sure at least some of the entries are functions in the _Concurrency

stdlib/public/Concurrency/DiscardingTaskGroup.swift

@@ -94,11 +94,16 @@ public func withDiscardingTaskGroup<GroupResult>(
   #endif
 }
 
+// Note: hack to stage out @_unsafeInheritExecutor forms of various functions
+// in favor of #isolation. The _unsafeInheritExecutor_ prefix is meaningful
+// to the type checker.
+//
+// This function also doubles as an ABI-compatibility shim predating the
+// introduction of #isolation.
 @available(SwiftStdlib 5.9, *)
-@usableFromInline
 @_unsafeInheritExecutor // for ABI compatibility
 @_silgen_name("$ss23withDiscardingTaskGroup9returning4bodyxxm_xs0bcD0VzYaXEtYalF")
-internal func __abi_withDiscardingTaskGroup<GroupResult>(
+public func _unsafeInheritExecutor_withDiscardingTaskGroup<GroupResult>(
   returning returnType: GroupResult.Type = GroupResult.self,
   body: (inout DiscardingTaskGroup) async -> GroupResult
 ) async -> GroupResult {
@@ -769,10 +774,9 @@ public func withThrowingDiscardingTaskGroup<GroupResult>(
 }
 
 @available(SwiftStdlib 5.9, *)
-@usableFromInline
 @_unsafeInheritExecutor // for ABI compatibility
 @_silgen_name("$ss31withThrowingDiscardingTaskGroup9returning4bodyxxm_xs0bcdE0Vys5Error_pGzYaKXEtYaKlF")
-internal func __abi_withThrowingDiscardingTaskGroup<GroupResult>(
+public func _unsafeInheritExecutor_withThrowingDiscardingTaskGroup<GroupResult>(
     returning returnType: GroupResult.Type = GroupResult.self,
     body: (inout ThrowingDiscardingTaskGroup<Error>) async throws -> GroupResult
 ) async throws -> GroupResult {

stdlib/public/Concurrency/Task+TaskExecutor.swift

@@ -159,11 +159,17 @@ public func withTaskExecutorPreference<T, Failure>(
   return try await operation()
 }
 
+// Note: hack to stage out @_unsafeInheritExecutor forms of various functions
+// in favor of #isolation. The _unsafeInheritExecutor_ prefix is meaningful
+// to the type checker.
+//
+// This function also doubles as an ABI-compatibility shim predating the
+// introduction of #isolation.
 @_unavailableInEmbedded
 @available(SwiftStdlib 6.0, *)
 @_unsafeInheritExecutor // for ABI compatibility
 @_silgen_name("$ss26withTaskExecutorPreference_9operationxSch_pSg_xyYaYbKXEtYaKs8SendableRzlF")
-public func __abi__withTaskExecutorPreference<T: Sendable>(
+public func _unsafeInheritExecutor_withTaskExecutorPreference<T: Sendable>(
   _ taskExecutor: (any TaskExecutor)?,
   operation: @Sendable () async throws -> T
 ) async rethrows -> T {

stdlib/public/Concurrency/TaskGroup.swift

@@ -90,11 +90,17 @@ public func withTaskGroup<ChildTaskResult, GroupResult>(
   #endif
 }
 
+// Note: hack to stage out @_unsafeInheritExecutor forms of various functions
+// in favor of #isolation. The _unsafeInheritExecutor_ prefix is meaningful
+// to the type checker.
+//
+// This function also doubles as an ABI-compatibility shim predating the
+// introduction of #isolation.
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("$ss13withTaskGroup2of9returning4bodyq_xm_q_mq_ScGyxGzYaXEtYar0_lF")
 @_unsafeInheritExecutor // for ABI compatibility
 @inlinable
-public func withTaskGroup<ChildTaskResult, GroupResult>(
+public func _unsafeInheritExecutor_withTaskGroup<ChildTaskResult, GroupResult>(
   of childTaskResultType: ChildTaskResult.Type,
   returning returnType: GroupResult.Type = GroupResult.self,
   body: (inout TaskGroup<ChildTaskResult>) async -> GroupResult
@@ -228,11 +234,16 @@ public func withThrowingTaskGroup<ChildTaskResult, GroupResult>(
   #endif
 }
 
+// Note: hack to stage out @_unsafeInheritExecutor forms of various functions
+// in favor of #isolation. The _unsafeInheritExecutor_ prefix is meaningful
+// to the type checker.
+//
+// This function also doubles as an ABI-compatibility shim predating the
+// introduction of #isolation.
 @available(SwiftStdlib 5.1, *)
 @_silgen_name("$ss21withThrowingTaskGroup2of9returning4bodyq_xm_q_mq_Scgyxs5Error_pGzYaKXEtYaKr0_lF")
 @_unsafeInheritExecutor // for ABI compatibility
-@usableFromInline
-internal func withThrowingTaskGroup<ChildTaskResult, GroupResult>(
+public func _unsafeInheritExecutor_withThrowingTaskGroup<ChildTaskResult, GroupResult>(
   of childTaskResultType: ChildTaskResult.Type,
   returning returnType: GroupResult.Type = GroupResult.self,
   body: (inout ThrowingTaskGroup<ChildTaskResult, Error>) async throws -> GroupResult

stdlib/public/Concurrency/TaskLocal.swift

@@ -265,14 +265,16 @@ public final class TaskLocal<Value: Sendable>: Sendable, CustomStringConvertible
     return try await operation()
   }
 
+  @_silgen_name("$ss9TaskLocalC13withValueImpl_9operation4file4lineqd__xn_qd__yYaKXESSSutYaKlF")
   @inlinable
   @discardableResult
   @_unsafeInheritExecutor // internal for backwards compatibility; though may be able to be removed safely?
   @available(SwiftStdlib 5.1, *)
-  @backDeployed(before: SwiftStdlib 5.9)
-  internal func withValueImpl<R>(_ valueDuringOperation: __owned Value,
-                                 operation: () async throws -> R,
-                                 file: String = #fileID, line: UInt = #line) async rethrows -> R {
+  internal func _unsafeInheritExecutor_withValueImpl<R>(
+    _ valueDuringOperation: __owned Value,
+    operation: () async throws -> R,
+    file: String = #fileID, line: UInt = #line
+  ) async rethrows -> R {
     _taskLocalValuePush(key: key, value: consume valueDuringOperation)
     defer { _taskLocalValuePop() }
 

test/Concurrency/unsafe_inherit_executor.swift

@@ -88,8 +88,12 @@ enum TL {
   static var string: String = "<undefined>"
 }
 
+enum MyError: Error {
+case fail
+}
+
 @_unsafeInheritExecutor
-func unsafeCallerAvoidsNewLoop() async throws {
+func unsafeCallerAvoidsNewLoop(clock: some Clock) async throws {
   // expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}
 
   _ = await withUnsafeContinuation { (continuation: UnsafeContinuation<Int, Never>) in
@@ -113,10 +117,62 @@ func unsafeCallerAvoidsNewLoop() async throws {
   } onCancel: {
   }
 
-  await TL.$string.withValue("hello") {
+  TL.$string.withValue("hello") {
+    print(TL.string)
+  }
+
+  try await TL.$string.withValue("hello") {
+    try await Task.sleep(nanoseconds: 500)
     print(TL.string)
   }
 
   func operation() async throws -> Int { 7 }
   try await TL.$string.withValue("hello", operation: operation)
+
+  // FIXME: Clock.measure does not currently support this hack.
+  // expected-error@+1{{#isolation (introduced by a default argument) cannot be used within an '@_unsafeInheritExecutor' function}}
+  _ = try! await clock.measure {
+    print("so very slow")
+    try await Task.sleep(nanoseconds: 500)
+  }
+
+  _ = await withDiscardingTaskGroup(returning: Int.self) { group in
+    group.addTask {
+      print("hello")
+    }
+
+    return 5
+  }
+
+  _ = try await withThrowingDiscardingTaskGroup(returning: Int.self) { group in
+    group.addTask {
+      print("hello")
+    }
+
+    return 5
+  }
+
+  _ = await withTaskExecutorPreference(nil) {
+    print("hello")
+  }
+
+  _ = await withTaskGroup(of: Int.self, returning: Int.self) { group in
+    group.addTask {
+      return 5
+    }
+
+    return 5
+  }
+
+  _ = try await withThrowingTaskGroup(of: Int.self, returning: Int.self) { group in
+    group.addTask {
+      throw MyError.fail
+    }
+
+    throw MyError.fail
+  }
 }
+
+@_unsafeInheritExecutor
+func _unsafeInheritExecutor_hacky() async { }
+// expected-warning@-1{{@_unsafeInheritExecutor attribute is deprecated; consider an 'isolated' parameter defaulted to '#isolation' instead}}

test/api-digester/stability-concurrency-abi.test

@@ -118,6 +118,12 @@ Func TaskLocal.withValue(_:operation:file:line:) has parameter 1 type change fro
 Func TaskLocal.withValue(_:operation:file:line:) has parameter 1 type change from () throws -> τ_1_0 to () async throws -> τ_1_0
 Func TaskLocal.withValue(_:operation:file:line:) has parameter 2 type change from Swift.String to (any _Concurrency.Actor)?
 Func TaskLocal.withValue(_:operation:file:line:) has parameter 3 type change from Swift.UInt to Swift.String
+Func withTaskGroup(of:returning:body:) has parameter 2 type change from (inout _Concurrency.TaskGroup<τ_0_0>) async -> τ_0_1 to (any _Concurrency.Actor)?
+Func withThrowingTaskGroup(of:returning:body:) has been renamed to Func withThrowingTaskGroup(of:returning:isolation:body:)
+Func withThrowingTaskGroup(of:returning:body:) has mangled name changing from '_Concurrency.withThrowingTaskGroup<A, B where A: Swift.Sendable>(of: A.Type, returning: B.Type, body: (inout Swift.ThrowingTaskGroup<A, Swift.Error>) async throws -> B) async throws -> B' to '_Concurrency.withThrowingTaskGroup<A, B where A: Swift.Sendable>(of: A.Type, returning: B.Type, isolation: isolated Swift.Optional<Swift.Actor>, body: (inout Swift.ThrowingTaskGroup<A, Swift.Error>) async throws -> B) async throws -> B'
+Func withThrowingTaskGroup(of:returning:body:) has parameter 2 type change from (inout _Concurrency.ThrowingTaskGroup<τ_0_0, any Swift.Error>) async throws -> τ_0_1 to (any _Concurrency.Actor)?
+Func withTaskGroup(of:returning:body:) has been renamed to Func withTaskGroup(of:returning:isolation:body:)
+Func withTaskGroup(of:returning:body:) has mangled name changing from '_Concurrency.withTaskGroup<A, B where A: Swift.Sendable>(of: A.Type, returning: B.Type, body: (inout Swift.TaskGroup<A>) async -> B) async -> B' to '_Concurrency.withTaskGroup<A, B where A: Swift.Sendable>(of: A.Type, returning: B.Type, isolation: isolated Swift.Optional<Swift.Actor>, body: (inout Swift.TaskGroup<A>) async -> B) async -> B'
 
 // *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment above.)