Reland "[vm] Fix some async* semantics issues: Only run generator if there's active subscription (not paused/cancelled)"
This fixes an issue where VM would run the async* generator after a
`yield` / `yield*` even though the subscription may be paused or
cancelled.
Furthermore this fixes an issue where `StackTrace.current` used
in async* generator crashes VM and/or produces truncated stack
trace.
This fixes the following existing tests that were failing before:
* co19/Language/Statements/Yield_and_Yield_Each/Yield_Each/execution_async_t08
* co19/Language/Statements/Yield_and_Yield_Each/Yield_Each/execution_async_t09
* co19/Language/Statements/Yield_and_Yield_Each/Yield_Each/execution_async_t10
* language/async_star/async_star_cancel_test
* language/async_star/pause_test
New in reland: Allow the generator to to cause cancelling it's own consumer.
This addresses the issue of original revert
-> see https://github.com/flutter/flutter/issues/101514
Issue https://github.com/flutter/flutter/issues/100441
Issue https://github.com/dart-lang/sdk/issues/48695
Issue https://github.com/dart-lang/sdk/issues/34775
TEST=vm/dart{,_2}/causal_stacks/flutter_regress_100441_test
Change-Id: I091b7159d59ea15fc31162b4b6b17260d523d7cb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/242400
Reviewed-by: Lasse Nielsen <lrn@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
diff --git a/pkg/front_end/testcases/general/async_function.dart.weak.transformed.expect b/pkg/front_end/testcases/general/async_function.dart.weak.transformed.expect
index 373a8d8..aea2b09 100644
--- a/pkg/front_end/testcases/general/async_function.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/general/async_function.dart.weak.transformed.expect
@@ -121,10 +121,10 @@
return null;
else
[yield] null;
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::asyncStarString2()){(asy::Stream<core::String>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::asyncStarString2()){(asy::Stream<core::String>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
[yield] let dynamic #t1 = asy::_awaitHelper(self::asyncString(), :async_op_then, :async_op_error) in null;
if(:controller.{asy::_AsyncStarStreamController::add}(_in::unsafeCast<core::String>(:result_or_exception)){(core::String) → core::bool})
return null;
diff --git a/pkg/front_end/testcases/general/await_complex.dart.weak.transformed.expect b/pkg/front_end/testcases/general/await_complex.dart.weak.transformed.expect
index d3d1139..7af3671 100644
--- a/pkg/front_end/testcases/general/await_complex.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/general/await_complex.dart.weak.transformed.expect
@@ -652,10 +652,10 @@
#L16:
{
[yield] let dynamic #t55 = asy::_awaitHelper(func<asy::Stream<core::int>>(self::intStream()){(asy::Stream<core::int>) → FutureOr<asy::Stream<core::int>>}, :async_op_then, :async_op_error) in null;
- if(:controller.{asy::_AsyncStarStreamController::addStream}(_in::unsafeCast<asy::Stream<core::int>>(:result_or_exception)){(asy::Stream<core::int>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(_in::unsafeCast<asy::Stream<core::int>>(:result_or_exception)){(asy::Stream<core::int>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/front_end/testcases/general/statements.dart.weak.transformed.expect b/pkg/front_end/testcases/general/statements.dart.weak.transformed.expect
index 012142b..2db299f 100644
--- a/pkg/front_end/testcases/general/statements.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/general/statements.dart.weak.transformed.expect
@@ -44,10 +44,10 @@
return null;
else
[yield] null;
- if(:controller.{asy::_AsyncStarStreamController::addStream}(x as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Stream<dynamic>){(asy::Stream<dynamic>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(x as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Stream<dynamic>){(asy::Stream<dynamic>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
}
else
diff --git a/pkg/front_end/testcases/inference/block_bodied_lambdas_async_star.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/block_bodied_lambdas_async_star.dart.weak.transformed.expect
index 2e127fbc..5730a20 100644
--- a/pkg/front_end/testcases/inference/block_bodied_lambdas_async_star.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/block_bodied_lambdas_async_star.dart.weak.transformed.expect
@@ -2,6 +2,7 @@
import self as self;
import "dart:async" as asy;
import "dart:core" as core;
+import "dart:_internal" as _in;
import "dart:async";
@@ -25,10 +26,10 @@
else
[yield] null;
asy::Stream<core::double*>* s;
- if(:controller.{asy::_AsyncStarStreamController::addStream}(s){(asy::Stream<core::num*>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(s){(asy::Stream<core::num*>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart.weak.transformed.expect
index 7f9840f..02bca84 100644
--- a/pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart.weak.transformed.expect
@@ -29,6 +29,7 @@
import self as self;
import "dart:core" as core;
import "dart:async" as asy;
+import "dart:_internal" as _in;
import "dart:async";
@@ -109,18 +110,18 @@
return null;
else
[yield] null;
- if(:controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart:17:64: Error: A value of type 'List<dynamic>' can't be assigned to a variable of type 'Stream<List<int>>'.
+ :controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/inference/downwards_inference_yield_yield_star.dart:17:64: Error: A value of type 'List<dynamic>' can't be assigned to a variable of type 'Stream<List<int>>'.
- 'List' is from 'dart:core'.
- 'Stream' is from 'dart:async'.
yield* /*error:YIELD_OF_INVALID_TYPE*/ /*@typeArgs=dynamic*/ [];
- ^" in core::_GrowableList::•<dynamic>(0) as{TypeError} asy::Stream<core::List<core::int*>*>*){(asy::Stream<core::List<core::int*>*>) → core::bool})
+ ^" in core::_GrowableList::•<dynamic>(0) as{TypeError} asy::Stream<core::List<core::int*>*>*){(asy::Stream<core::List<core::int*>*>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::MyStream::•<core::List<core::int*>*>()){(asy::Stream<core::List<core::int*>*>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::MyStream::•<core::List<core::int*>*>()){(asy::Stream<core::List<core::int*>*>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/front_end/testcases/inference/local_return_and_yield.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/local_return_and_yield.dart.weak.transformed.expect
index fbcd719..251c281 100644
--- a/pkg/front_end/testcases/inference/local_return_and_yield.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/local_return_and_yield.dart.weak.transformed.expect
@@ -10,6 +10,7 @@
import self as self;
import "dart:core" as core;
import "dart:async" as asy;
+import "dart:_internal" as _in;
import "dart:async";
@@ -129,10 +130,10 @@
try {
#L3:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(asy::Stream::fromIterable<(core::int*) →* core::int*>(core::_GrowableList::_literal1<(core::int*) →* core::int*>((core::int* x) → core::int* => x))){(asy::Stream<(core::int*) →* core::int*>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(asy::Stream::fromIterable<(core::int*) →* core::int*>(core::_GrowableList::_literal1<(core::int*) →* core::int*>((core::int* x) → core::int* => x))){(asy::Stream<(core::int*) →* core::int*>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/front_end/testcases/inference/top_level_return_and_yield.dart.weak.transformed.expect b/pkg/front_end/testcases/inference/top_level_return_and_yield.dart.weak.transformed.expect
index 84ea22c..3d5e979 100644
--- a/pkg/front_end/testcases/inference/top_level_return_and_yield.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/inference/top_level_return_and_yield.dart.weak.transformed.expect
@@ -10,6 +10,7 @@
import self as self;
import "dart:core" as core;
import "dart:async" as asy;
+import "dart:_internal" as _in;
import "dart:async";
@@ -128,10 +129,10 @@
try {
#L3:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(asy::Stream::fromIterable<(core::int*) →* core::int*>(core::_GrowableList::_literal1<(core::int*) →* core::int*>((core::int* x) → core::int* => x))){(asy::Stream<(core::int*) →* core::int*>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(asy::Stream::fromIterable<(core::int*) →* core::int*>(core::_GrowableList::_literal1<(core::int*) →* core::int*>((core::int* x) → core::int* => x))){(asy::Stream<(core::int*) →* core::int*>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/front_end/testcases/nnbd/issue41437c.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/issue41437c.dart.strong.transformed.expect
index cfc0b05..c8058e6 100644
--- a/pkg/front_end/testcases/nnbd/issue41437c.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/nnbd/issue41437c.dart.strong.transformed.expect
@@ -40,6 +40,7 @@
import self as self;
import "dart:async" as asy;
import "dart:core" as core;
+import "dart:_internal" as _in;
static method getNull() → dynamic
return null;
@@ -160,13 +161,13 @@
try {
#L4:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:21:10: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
+ :controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:21:10: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
- 'Stream' is from 'dart:async'.
yield* getStreamNull(); // error
- ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → core::bool})
+ ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -203,10 +204,10 @@
try {
#L5:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -285,13 +286,13 @@
try {
#L8:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:38:12: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
+ :controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:38:12: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
- 'Stream' is from 'dart:async'.
yield* getStreamNull(); // error
- ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → core::bool})
+ ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -328,10 +329,10 @@
try {
#L9:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -402,10 +403,10 @@
try {
#L11:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamNull()){(asy::Stream<dynamic>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamNull()){(asy::Stream<dynamic>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -440,10 +441,10 @@
try {
#L12:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/front_end/testcases/nnbd/issue41437c.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/issue41437c.dart.weak.transformed.expect
index cfc0b05..c8058e6 100644
--- a/pkg/front_end/testcases/nnbd/issue41437c.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/nnbd/issue41437c.dart.weak.transformed.expect
@@ -40,6 +40,7 @@
import self as self;
import "dart:async" as asy;
import "dart:core" as core;
+import "dart:_internal" as _in;
static method getNull() → dynamic
return null;
@@ -160,13 +161,13 @@
try {
#L4:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:21:10: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
+ :controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:21:10: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
- 'Stream' is from 'dart:async'.
yield* getStreamNull(); // error
- ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → core::bool})
+ ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -203,10 +204,10 @@
try {
#L5:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -285,13 +286,13 @@
try {
#L8:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:38:12: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
+ :controller.{asy::_AsyncStarStreamController::addStream}(invalid-expression "pkg/front_end/testcases/nnbd/issue41437c.dart:38:12: Error: A value of type 'Stream<dynamic>' can't be assigned to a variable of type 'Stream<bool>'.
- 'Stream' is from 'dart:async'.
yield* getStreamNull(); // error
- ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → core::bool})
+ ^" in self::getStreamNull() as{TypeError,ForNonNullableByDefault} asy::Stream<core::bool>){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -328,10 +329,10 @@
try {
#L9:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -402,10 +403,10 @@
try {
#L11:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamNull()){(asy::Stream<dynamic>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamNull()){(asy::Stream<dynamic>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
@@ -440,10 +441,10 @@
try {
#L12:
{
- if(:controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → core::bool})
+ :controller.{asy::_AsyncStarStreamController::addStream}(self::getStreamBool()){(asy::Stream<core::bool>) → void};
+ [yield] null;
+ if(_in::unsafeCast<core::bool>(:result_or_exception))
return null;
- else
- [yield] null;
}
return;
}
diff --git a/pkg/vm/lib/transformations/continuation.dart b/pkg/vm/lib/transformations/continuation.dart
index 455b281..f158e8e 100644
--- a/pkg/vm/lib/transformations/continuation.dart
+++ b/pkg/vm/lib/transformations/continuation.dart
@@ -1329,10 +1329,21 @@
functionType: addMethodFunctionType)
..fileOffset = stmt.fileOffset;
- statements.add(new IfStatement(
- addExpression,
- new ReturnStatement(new NullLiteral()),
- createContinuationPoint()..fileOffset = stmt.fileOffset));
+ if (stmt.isYieldStar) {
+ statements.add(ExpressionStatement(addExpression));
+ statements.add(createContinuationPoint()..fileOffset = stmt.fileOffset);
+ final wasCancelled = StaticInvocation(
+ helper.unsafeCast,
+ Arguments(<Expression>[VariableGet(expressionRewriter!.asyncResult)],
+ types: <DartType>[helper.coreTypes.boolNonNullableRawType]));
+ statements
+ .add(IfStatement(wasCancelled, ReturnStatement(NullLiteral()), null));
+ } else {
+ statements.add(new IfStatement(
+ addExpression,
+ new ReturnStatement(new NullLiteral()),
+ createContinuationPoint()..fileOffset = stmt.fileOffset));
+ }
return removalSentinel ?? EmptyStatement();
}
diff --git a/runtime/tests/vm/dart/causal_stacks/flutter_regress_100441_test.dart b/runtime/tests/vm/dart/causal_stacks/flutter_regress_100441_test.dart
new file mode 100644
index 0000000..b5ff8ad
--- /dev/null
+++ b/runtime/tests/vm/dart/causal_stacks/flutter_regress_100441_test.dart
@@ -0,0 +1,77 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// VMOptions=--lazy-async-stacks
+
+import 'dart:async';
+
+import 'package:expect/expect.dart';
+
+import 'utils.dart' show assertStack;
+
+String effectOrder = '';
+StackTrace? stackAfterYield = null;
+
+void emit(String m) => effectOrder += m;
+
+main() async {
+ emit('1');
+ await for (final value in produce()) {
+ emit('5');
+ Expect.equals('|value|', value);
+ }
+ emit('8');
+ Expect.equals('12345678', effectOrder);
+
+ assertStack(const <String>[
+ r'^#0 produceInner .*$',
+ r'^<asynchronous suspension>$',
+ r'^#1 produce .*$',
+ r'^<asynchronous suspension>$',
+ r'^#2 main .*$',
+ r'^<asynchronous suspension>$',
+ ], stackAfterYield!);
+
+ effectOrder = '';
+
+ emit('1');
+ await for (final value in produceYieldStar()) {
+ emit('5');
+ Expect.equals('|value|', value);
+ break;
+ }
+ emit('6');
+ Expect.equals('123456', effectOrder);
+}
+
+Stream<dynamic> produce() async* {
+ emit('2');
+ await for (String response in produceInner()) {
+ emit('4');
+ yield response;
+ }
+ emit('7');
+}
+
+Stream produceInner() async* {
+ emit('3');
+ yield '|value|';
+ emit('6');
+ stackAfterYield = StackTrace.current;
+}
+
+Stream<dynamic> produceYieldStar() async* {
+ emit('2');
+ await for (String response in produceInner()) {
+ emit('4');
+ yield response;
+ }
+ emit('x');
+}
+
+Stream produceInnerYieldStar() async* {
+ emit('3');
+ yield* Stream.fromIterable(['|value|', '|value2|']);
+ emit('x');
+}
diff --git a/runtime/tests/vm/dart/flutter_regress_101514_test.dart b/runtime/tests/vm/dart/flutter_regress_101514_test.dart
new file mode 100644
index 0000000..6c78710
--- /dev/null
+++ b/runtime/tests/vm/dart/flutter_regress_101514_test.dart
@@ -0,0 +1,21 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:expect/expect.dart';
+
+late StreamSubscription sub;
+
+main() async {
+ sub = foo().listen((_) => throw 'unexpected item');
+}
+
+Stream<int> foo() async* {
+ // While the generator (i.e. this funtion) runs, we cancel the consumer and
+ // try to yield more.
+ sub.cancel();
+ yield* Stream.fromIterable([1, 2, 3]);
+ throw 'should not run';
+}
diff --git a/runtime/tests/vm/dart_2/causal_stacks/flutter_regress_100441_test.dart b/runtime/tests/vm/dart_2/causal_stacks/flutter_regress_100441_test.dart
new file mode 100644
index 0000000..2d4d2ef
--- /dev/null
+++ b/runtime/tests/vm/dart_2/causal_stacks/flutter_regress_100441_test.dart
@@ -0,0 +1,78 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// VMOptions=--lazy-async-stacks
+
+// @dart = 2.9
+import 'dart:async';
+
+import 'package:expect/expect.dart';
+
+import 'utils.dart' show assertStack;
+
+String effectOrder = '';
+StackTrace stackAfterYield = null;
+
+void emit(String m) => effectOrder += m;
+
+main() async {
+ emit('1');
+ await for (final value in produce()) {
+ emit('5');
+ Expect.equals('|value|', value);
+ }
+ emit('8');
+ Expect.equals('12345678', effectOrder);
+
+ assertStack(const <String>[
+ r'^#0 produceInner .*$',
+ r'^<asynchronous suspension>$',
+ r'^#1 produce .*$',
+ r'^<asynchronous suspension>$',
+ r'^#2 main .*$',
+ r'^<asynchronous suspension>$',
+ ], stackAfterYield);
+
+ effectOrder = '';
+
+ emit('1');
+ await for (final value in produceYieldStar()) {
+ emit('5');
+ Expect.equals('|value|', value);
+ break;
+ }
+ emit('6');
+ Expect.equals('123456', effectOrder);
+}
+
+Stream<dynamic> produce() async* {
+ emit('2');
+ await for (String response in produceInner()) {
+ emit('4');
+ yield response;
+ }
+ emit('7');
+}
+
+Stream produceInner() async* {
+ emit('3');
+ yield '|value|';
+ emit('6');
+ stackAfterYield = StackTrace.current;
+}
+
+Stream<dynamic> produceYieldStar() async* {
+ emit('2');
+ await for (String response in produceInner()) {
+ emit('4');
+ yield response;
+ }
+ emit('x');
+}
+
+Stream produceInnerYieldStar() async* {
+ emit('3');
+ yield* Stream.fromIterable(['|value|', '|value2|']);
+ emit('x');
+}
diff --git a/runtime/tests/vm/dart_2/flutter_regress_101514_test.dart b/runtime/tests/vm/dart_2/flutter_regress_101514_test.dart
new file mode 100644
index 0000000..44d029a
--- /dev/null
+++ b/runtime/tests/vm/dart_2/flutter_regress_101514_test.dart
@@ -0,0 +1,23 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.9
+
+import 'dart:async';
+
+import 'package:expect/expect.dart';
+
+StreamSubscription sub;
+
+main() async {
+ sub = foo().listen((_) => throw 'unexpected item');
+}
+
+Stream<int> foo() async* {
+ // While the generator (i.e. this funtion) runs, we cancel the consumer and
+ // try to yield more.
+ sub.cancel();
+ yield* Stream.fromIterable([1, 2, 3]);
+ throw 'should not run';
+}
diff --git a/runtime/vm/stack_trace.cc b/runtime/vm/stack_trace.cc
index 4c7cbcf..eee21f8 100644
--- a/runtime/vm/stack_trace.cc
+++ b/runtime/vm/stack_trace.cc
@@ -71,7 +71,7 @@
future_listener_class(Class::Handle(zone)),
async_start_stream_controller_class(Class::Handle(zone)),
stream_controller_class(Class::Handle(zone)),
- async_stream_controller_class(Class::Handle(zone)),
+ sync_stream_controller_class(Class::Handle(zone)),
controller_subscription_class(Class::Handle(zone)),
buffering_stream_subscription_class(Class::Handle(zone)),
stream_iterator_class(Class::Handle(zone)),
@@ -100,9 +100,9 @@
stream_controller_class =
async_lib.LookupClassAllowPrivate(Symbols::_StreamController());
ASSERT(!stream_controller_class.IsNull());
- async_stream_controller_class =
- async_lib.LookupClassAllowPrivate(Symbols::_AsyncStreamController());
- ASSERT(!async_stream_controller_class.IsNull());
+ sync_stream_controller_class =
+ async_lib.LookupClassAllowPrivate(Symbols::_SyncStreamController());
+ ASSERT(!sync_stream_controller_class.IsNull());
controller_subscription_class =
async_lib.LookupClassAllowPrivate(Symbols::_ControllerSubscription());
ASSERT(!controller_subscription_class.IsNull());
@@ -171,7 +171,7 @@
const Instance& controller = Instance::Cast(context_entry_);
controller_ = controller.GetField(controller_controller_field);
ASSERT(!controller_.IsNull());
- ASSERT(controller_.GetClassId() == async_stream_controller_class.id());
+ ASSERT(controller_.GetClassId() == sync_stream_controller_class.id());
// Get the _StreamController._state field.
state_ = Instance::Cast(controller_).GetField(state_field);
@@ -209,7 +209,7 @@
// contains the iterator's value. In that case we cannot unwind anymore.
//
// Notice: With correct async* semantics this may never be true: The async*
- // generator should only be invoked to produce a vaue if there's an
+ // generator should only be invoked to produce a value if there's an
// in-progress `await streamIterator.moveNext()` call. Once such call has
// finished the async* generator should be paused/yielded until the next
// such call - and being paused/yielded means it should not appear in stack
diff --git a/runtime/vm/stack_trace.h b/runtime/vm/stack_trace.h
index 0683cf7..58a4cba 100644
--- a/runtime/vm/stack_trace.h
+++ b/runtime/vm/stack_trace.h
@@ -78,7 +78,7 @@
Class& future_listener_class;
Class& async_start_stream_controller_class;
Class& stream_controller_class;
- Class& async_stream_controller_class;
+ Class& sync_stream_controller_class;
Class& controller_subscription_class;
Class& buffering_stream_subscription_class;
Class& stream_iterator_class;
diff --git a/runtime/vm/symbols.h b/runtime/vm/symbols.h
index 52ec048..f96d8d3 100644
--- a/runtime/vm/symbols.h
+++ b/runtime/vm/symbols.h
@@ -278,7 +278,6 @@
V(Values, "values") \
V(WeakSerializationReference, "WeakSerializationReference") \
V(_AsyncStarStreamController, "_AsyncStarStreamController") \
- V(_AsyncStreamController, "_AsyncStreamController") \
V(_BufferingStreamSubscription, "_BufferingStreamSubscription") \
V(_ByteBuffer, "_ByteBuffer") \
V(_ByteBufferDot_New, "_ByteBuffer._New") \
@@ -381,6 +380,7 @@
V(_StreamIterator, "_StreamIterator") \
V(_String, "String") \
V(_SyncIterator, "_SyncIterator") \
+ V(_SyncStreamController, "_SyncStreamController") \
V(_TransferableTypedDataImpl, "_TransferableTypedDataImpl") \
V(_Type, "_Type") \
V(_FunctionType, "_FunctionType") \
diff --git a/sdk/lib/_internal/vm/lib/async_patch.dart b/sdk/lib/_internal/vm/lib/async_patch.dart
index 2e322f1..3d4b20b 100644
--- a/sdk/lib/_internal/vm/lib/async_patch.dart
+++ b/sdk/lib/_internal/vm/lib/async_patch.dart
@@ -117,6 +117,13 @@
bool isSuspendedAtYield = false;
_Future? cancellationFuture = null;
+ /// Argument passed to the generator when it is resumed after an addStream.
+ ///
+ /// `true` if the generator should exit after `yield*` resumes.
+ /// `false` if the generator should continue after `yield*` resumes.
+ /// `null` otherwies.
+ bool? continuationArgument = null;
+
Stream<T> get stream {
final Stream<T> local = controller.stream;
if (local is _StreamImpl<T>) {
@@ -128,7 +135,9 @@
void runBody() {
isScheduled = false;
isSuspendedAtYield = false;
- asyncStarBody(null, null);
+ final bool? argument = continuationArgument;
+ continuationArgument = null;
+ asyncStarBody(argument, null);
}
void scheduleGenerator() {
@@ -152,11 +161,11 @@
bool add(T event) {
if (!onListenReceived) _fatal("yield before stream is listened to");
if (isSuspendedAtYield) _fatal("unexpected yield");
- // If stream is cancelled, tell caller to exit the async generator.
+ controller.add(event);
if (!controller.hasListener) {
return true;
}
- controller.add(event);
+
scheduleGenerator();
isSuspendedAtYield = true;
return false;
@@ -165,22 +174,41 @@
// Adds the elements of stream into this controller's stream.
// The generator will be scheduled again when all of the
// elements of the added stream have been consumed.
- // Returns true if the caller should terminate
- // execution of the generator.
- bool addStream(Stream<T> stream) {
+ void addStream(Stream<T> stream) {
if (!onListenReceived) _fatal("yield before stream is listened to");
- // If stream is cancelled, tell caller to exit the async generator.
- if (!controller.hasListener) return true;
+
+ if (exitAfterYieldStarIfCancelled()) return;
+
isAdding = true;
- var whenDoneAdding = controller.addStream(stream, cancelOnError: false);
+ final whenDoneAdding = controller.addStream(stream, cancelOnError: false);
whenDoneAdding.then((_) {
isAdding = false;
- scheduleGenerator();
- if (!isScheduled) isSuspendedAtYield = true;
+ if (exitAfterYieldStarIfCancelled()) return;
+ resumeNormallyAfterYieldStar();
});
+ }
+
+ /// Schedules the generator to exit after `yield*` if stream was cancelled.
+ ///
+ /// Returns `true` if generator is told to exit and `false` otherwise.
+ bool exitAfterYieldStarIfCancelled() {
+ // If consumer cancelled subscription we should tell async* generator to
+ // finish (i.e. run finally clauses and return).
+ if (!controller.hasListener) {
+ continuationArgument = true;
+ scheduleGenerator();
+ return true;
+ }
return false;
}
+ /// Schedules the generator to resume normally after `yield*`.
+ void resumeNormallyAfterYieldStar() {
+ continuationArgument = false;
+ scheduleGenerator();
+ if (!isScheduled) isSuspendedAtYield = true;
+ }
+
void addError(Object error, StackTrace stackTrace) {
// TODO(40614): Remove once non-nullability is sound.
ArgumentError.checkNotNull(error, "error");
@@ -211,7 +239,7 @@
}
_AsyncStarStreamController(this.asyncStarBody)
- : controller = new StreamController() {
+ : controller = new StreamController(sync: true) {
controller.onListen = this.onListen;
controller.onResume = this.onResume;
controller.onCancel = this.onCancel;
diff --git a/tests/language/async_star/pause2_test.dart b/tests/language/async_star/pause2_test.dart
index a240d3d..3df0223 100644
--- a/tests/language/async_star/pause2_test.dart
+++ b/tests/language/async_star/pause2_test.dart
@@ -72,8 +72,8 @@
f() async* {
int i = 0;
while (true) {
- yield i;
list.add(i);
+ yield i;
i++;
}
}
diff --git a/tests/language/async_star/throw_in_catch_test.dart b/tests/language/async_star/throw_in_catch_test.dart
index 88982e5..7509a00 100644
--- a/tests/language/async_star/throw_in_catch_test.dart
+++ b/tests/language/async_star/throw_in_catch_test.dart
@@ -115,7 +115,7 @@
test() async {
// TODO(sigurdm): These tests are too dependent on scheduling, and buffering
// behavior.
- await runTest(foo1, "abcYdgC", null, true);
+ await runTest(foo1, "abcYgC", null, true);
await runTest(foo2, "abcX", "Error", false);
await runTest(foo3, "abcYX", "Error", false);
await runTest(foo4, "abcYdYefX", "Error2", false);
diff --git a/tests/language_2/async_star/pause2_test.dart b/tests/language_2/async_star/pause2_test.dart
index 11e0429..f6e8d5f 100644
--- a/tests/language_2/async_star/pause2_test.dart
+++ b/tests/language_2/async_star/pause2_test.dart
@@ -74,8 +74,8 @@
f() async* {
int i = 0;
while (true) {
- yield i;
list.add(i);
+ yield i;
i++;
}
}
diff --git a/tests/language_2/async_star/throw_in_catch_test.dart b/tests/language_2/async_star/throw_in_catch_test.dart
index 57b6b0e..6a26245 100644
--- a/tests/language_2/async_star/throw_in_catch_test.dart
+++ b/tests/language_2/async_star/throw_in_catch_test.dart
@@ -118,7 +118,7 @@
test() async {
// TODO(sigurdm): These tests are too dependent on scheduling, and buffering
// behavior.
- await runTest(foo1, "abcYdgC", null, true);
+ await runTest(foo1, "abcYgC", null, true);
await runTest(foo2, "abcX", "Error", false);
await runTest(foo3, "abcYX", "Error", false);
await runTest(foo4, "abcYdYefX", "Error2", false);
