Make --sync-async the default for the VM.

Change-Id: Ic6d7bbc27835ea7b197cccf05724adb99e95dd51
Reviewed-on: https://dart-review.googlesource.com/57580
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>

CHANGELOG.md

@@ -13,6 +13,9 @@
 
 ### Dart VM
 
+* The VM now uses `--sync-async` by default. Users can still opt out by
+  providing the `--no-sync-async` flag.
+
 ### Tool Changes
 
 #### Analyzer

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart

@@ -533,15 +533,17 @@ abstract class DartCompletionContributorTest extends AbstractContextTest {
   }
 
   Future<E> performAnalysis<E>(int times, Completer<E> completer) async {
+    // Await a microtask. Otherwise the futures are chained and would
+    // resolve linearly using up the stack.
+    await null;
     if (completer.isCompleted) {
       return completer.future;
     }
     // We use a delayed future to allow microtask events to finish. The
-    // Future.value or Future() constructors use scheduleMicrotask themselves and
-    // would therefore not wait for microtask callbacks that are scheduled after
-    // invoking this method.
-    return new Future.delayed(
-        Duration.zero, () => performAnalysis(times - 1, completer));
+    // Future.value or Future.microtask() constructors use scheduleMicrotask
+    // themselves and would therefore not wait for microtask callbacks that
+    // are scheduled after invoking this method.
+    return new Future(() => performAnalysis(times - 1, completer));
   }
 
   void resolveSource(String path, String content) {

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -1939,6 +1939,8 @@ class AnalysisDriverScheduler {
    * priority first.
    */
   Future<Null> _run() async {
+    // Give other microtasks the time to run before doing the analysis cycle.
+    await null;
     Stopwatch timer = new Stopwatch()..start();
     PerformanceLogSection analysisSection;
     while (true) {

pkg/front_end/tool/_fasta/command_line.dart

@@ -212,7 +212,7 @@ const Map<String, dynamic> optionSpecification = const <String, dynamic>{
   "--sdk": Uri,
   "--strong": "--strong-mode",
   "--strong-mode": false,
-  "--sync-async": false,
+  "--sync-async": true,
   "--target": String,
   "--verbose": false,
   "--verify": false,

pkg/vm/bin/gen_kernel.dart

@@ -28,7 +28,8 @@ final ArgParser _argParser = new ArgParser(allowTrailingOptions: true)
           'Produce kernel file for AOT compilation (enables global transformations).',
       defaultsTo: false)
   ..addFlag('strong-mode', help: 'Enable strong mode', defaultsTo: true)
-  ..addFlag('sync-async', help: 'Start `async` functions synchronously')
+  ..addFlag('sync-async',
+      help: 'Start `async` functions synchronously', defaultsTo: true)
   ..addFlag('embed-sources',
       help: 'Embed source files in the generated kernel component',
       defaultsTo: true)

pkg/vm/lib/frontend_server.dart

@@ -48,7 +48,7 @@ ArgParser argParser = new ArgParser(allowTrailingOptions: true)
       help: 'Run compiler in strong mode (uses strong mode semantics)',
       defaultsTo: false)
   ..addFlag('sync-async',
-      help: 'Start `async` functions synchronously.', defaultsTo: false)
+      help: 'Start `async` functions synchronously.', defaultsTo: true)
   ..addFlag('tfa',
       help:
           'Enable global type flow analysis and related transformations in AOT mode.',

pkg/vm/test/frontend_server_test.dart

@@ -69,16 +69,16 @@ Future<int> main() async {
       )).captured;
       expect(capturedArgs.single['sdk-root'], equals('sdkroot'));
       expect(capturedArgs.single['strong'], equals(true));
-      expect(capturedArgs.single['sync-async'], equals(false));
+      expect(capturedArgs.single['sync-async'], equals(true));
     });
 
-    test('compile from command line (sync-async)', () async {
+    test('compile from command line (no-sync-async)', () async {
       final List<String> args = <String>[
         'server.dart',
         '--sdk-root',
         'sdkroot',
         '--strong',
-        '--sync-async',
+        '--no-sync-async',
       ];
       final int exitcode = await starter(args, compiler: compiler);
       expect(exitcode, equals(0));
@@ -89,7 +89,7 @@ Future<int> main() async {
       )).captured;
       expect(capturedArgs.single['sdk-root'], equals('sdkroot'));
       expect(capturedArgs.single['strong'], equals(true));
-      expect(capturedArgs.single['sync-async'], equals(true));
+      expect(capturedArgs.single['sync-async'], equals(false));
     });
 
     test('compile from command line with link platform', () async {

runtime/observatory/tests/service/async_single_step_out_test.dart

@@ -1,7 +1,7 @@
 // Copyright (c) 2017, 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=--error_on_bad_type --error_on_bad_override  --verbose_debug --async_debugger
+// VMOptions=--error_on_bad_type --error_on_bad_override  --verbose_debug --async_debugger --no-sync-async
 
 import 'dart:developer';
 import 'service_test_common.dart';

runtime/observatory/tests/service/service.status

@@ -78,8 +78,12 @@ async_scope_test: Pass, Slow
 *: Skip
 
 [ ($compiler == none || $compiler == precompiler) && ($runtime == dart_precompiled || $runtime == vm) ]
+async_step_out_test: RuntimeError # Issue 29158, Async debugging
+awaiter_async_stack_contents_test: RuntimeError # Issue 29158, Async debugging
 evaluate_activation_test/instance: RuntimeError # http://dartbug.com/20047
 evaluate_activation_test/scope: RuntimeError # http://dartbug.com/20047
+regress_28980_test: RuntimeError # Issue 29158, Async debugging
+set_library_debuggable_test: RuntimeError # Issue 29158, Async debugging
 
 [ $arch != ia32 || $arch != x64 || $system != linux ]
 get_native_allocation_samples_test: Skip # Unsupported.

runtime/vm/dart_api_impl_test.cc

@@ -4408,43 +4408,6 @@ TEST_CASE(DartAPI_NegativeNativeFieldAccess) {
   EXPECT(Dart_IsError(result));
 }
 
-TEST_CASE(DartAPI_NegativeNativeFieldInIsolateMessage) {
-  const char* kScriptChars =
-      "import 'dart:isolate';\n"
-      "import 'dart:nativewrappers';\n"
-      "echo(msg) {\n"
-      "  var data = msg[0];\n"
-      "  var reply = msg[1];\n"
-      "  reply.send('echoing ${data(1)}}');\n"
-      "}\n"
-      "class Test extends NativeFieldWrapperClass2 {\n"
-      "  Test(this.i, this.j);\n"
-      "  int i, j;\n"
-      "}\n"
-      "main() {\n"
-      "  var port = new RawReceivePort();\n"
-      "  var obj = new Test(1,2);\n"
-      "  var msg = [obj, port.sendPort];\n"
-      "  var snd = Isolate.spawn(echo, msg);\n"
-      "  port.handler = (msg) {\n"
-      "    port.close();\n"
-      "    print('from worker ${msg}');\n"
-      "  };\n"
-      "}\n";
-
-  CHECK_API_SCOPE(thread);
-  HANDLESCOPE(thread);
-
-  // Create a test library and Load up a test script in it.
-  Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
-
-  // Invoke 'main' which should spawn an isolate and try to send an
-  // object with native fields over to the spawned isolate. This
-  // should result in an unhandled exception which is checked.
-  Dart_Handle retobj = Dart_Invoke(lib, NewString("main"), 0, NULL);
-  EXPECT(Dart_IsError(retobj));
-}
-
 TEST_CASE(DartAPI_GetStaticField_RunsInitializer) {
   const char* kScriptChars =
       "class TestClass  {\n"

runtime/vm/flag_list.h

@@ -152,7 +152,7 @@
   C(stress_async_stacks, false, false, bool, false,                            \
     "Stress test async stack traces")                                          \
   P(strong, bool, false, "Enable strong mode.")                                \
-  P(sync_async, bool, false, "Start `async` functions synchronously.")         \
+  P(sync_async, bool, true, "Start `async` functions synchronously.")          \
   R(support_ast_printer, false, bool, true, "Support the AST printer.")        \
   R(support_compiler_stats, false, bool, true, "Support compiler stats.")      \
   R(support_disassembler, false, bool, true, "Support the disassembler.")      \

runtime/vm/kernel_isolate.cc

@@ -88,7 +88,7 @@ class RunKernelTask : public ThreadPool::Task {
     api_flags.enable_error_on_bad_override = false;
     api_flags.reify_generic_functions = false;
     api_flags.strong = false;
-    api_flags.sync_async = false;
+    api_flags.sync_async = true;
 #if !defined(DART_PRECOMPILER) && !defined(TARGET_ARCH_DBC)
     api_flags.use_field_guards = true;
 #endif

tests/co19/co19-runtime.status

@@ -168,6 +168,7 @@ LibTest/typed_data/Int32List/buffer_A01_t02: Pass, Timeout # Flutter Issue 9109
 
 [ $runtime == vm ]
 Language/Classes/Constructors/Generative_Constructors/execution_of_an_initializer_t02: MissingCompileTimeError # Issue 114
+Language/Expressions/Function_Invocation/async_invokation_t02: RuntimeError # sync-async is on by default.
 LibTest/isolate/Isolate/spawnUri_A01_t06: Pass, Fail # Issue 28269, These tests are timing dependent and should be non-flaky once the fix for https://github.com/dart-lang/co19/issues/86 is merged into master. (They are skipped on $runtime == pre_compiled below.)
 LibTest/isolate/Isolate/spawnUri_A01_t07: Pass, Fail # Issue 28269, These tests are timing dependent and should be non-flaky once the fix for https://github.com/dart-lang/co19/issues/86 is merged into master. (They are skipped on $runtime == pre_compiled below.)
 LibTest/isolate/Isolate/spawn_A04_t01: Pass, Fail # Issue 28269, These tests are timing dependent and should be non-flaky once the fix for https://github.com/dart-lang/co19/issues/86 is merged into master. (They are skipped on $runtime == pre_compiled below.)

tests/language/language.status

@@ -474,6 +474,10 @@ vm/causal_async_exception_stack_test: SkipByDesign # Causal async stacks are not
 
 [ $runtime == dart_precompiled || $runtime == vm ]
 arithmetic_test: CompileTimeError # Large integer literal
+async_await_test: RuntimeError # sync-async is on by default
+asyncstar_throw_in_catch_test: RuntimeError # sync-async is on by default
+await_nonfuture_test: RuntimeError # sync-async is on by default
+await_not_started_immediately_test: RuntimeError # sync-async is on by default
 bit_operations_test: CompileTimeError # Large integer literal
 deopt_inlined_function_lazy_test: CompileTimeError # Large integer literal
 guess_cid_test: CompileTimeError # Large integer literal

tests/lib/lib.status

@@ -153,6 +153,7 @@ typed_data/float32x4_test: Fail, Pass # Safari has an optimization bug (nightlie
 typed_data/int32x4_test: Fail, Pass # Safari has an optimization bug (nightlies are already fine).
 
 [ $runtime == vm ]
+async/async_await_sync_completer_test: RuntimeError # sync-async is on by default.
 convert/streamed_conversion_json_utf8_decode_test: Pass, Slow # Infrequent timeouts.
 
 [ !$checked ]

tests/lib_2/isolate/native_wrapper_message_test.dart

@@ -0,0 +1,34 @@
+// Copyright (c) 2018, 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:isolate';
+import 'dart:nativewrappers';
+import 'package:expect/expect.dart';
+import 'package:async_helper/async_helper.dart';
+
+echo(msg) {
+  var data = msg[0];
+  var reply = msg[1];
+  reply.send('echoing ${data(1)}}');
+}
+
+class Test extends NativeFieldWrapperClass2 {
+  Test(this.i, this.j);
+  int i, j;
+}
+
+main() {
+  var port = new RawReceivePort();
+  var obj = new Test(1, 2);
+  var msg = [obj, port.sendPort];
+  var snd = Isolate.spawn(echo, msg);
+
+  asyncStart();
+  snd.catchError((e) {
+    Expect.isTrue(e is ArgumentError);
+    Expect.isTrue("$e".contains("NativeWrapper"));
+    port.close();
+    asyncEnd();
+  });
+}

tests/lib_2/lib_2_vm.status

@@ -2,6 +2,9 @@
 # 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.
 
+[ $runtime != vm ]
+isolate/native_wrapper_message_test: Skip # A VM specific test.
+
 [ $arch == arm64 && $runtime == vm ]
 mirrors/immutable_collections_test: Pass, Slow # http://dartbug.com/33057