Dart2js async-await. Propagate stacktraces from futures.

tests/compiler/dart2js_extra/async_stacktrace_test.dart

+// Copyright (c) 2015, 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";
+import "package:async_helper/async_helper.dart";
+
+class Tracer {
+  final String expected;
+  final String name;
+  String _trace = "";
+
+  Tracer(this.expected, [this.name]);
+
+  void trace(msg) {
+    if (name != null) {
+      print("Tracing $name: $msg");
+    }
+    _trace += msg;
+  }
+
+  void done() {
+    Expect.equals(expected, _trace);
+  }
+}
+
+test1(Tracer tracer) {
+  foo() async
+              * /// asyncStar: ok
+               {
+    var savedStackTrace;
+    try {
+      try {
+        tracer.trace("a");
+        throw "Error";
+      } catch (e, st) {
+        tracer.trace("b");
+        savedStackTrace = st;
+      }
+      tracer.trace("c");
+      await new Future.error("Error 2", savedStackTrace);
+      tracer.trace("d");
+    } catch (e, st) {
+      tracer.trace("e");
+      Expect.equals(savedStackTrace.toString(), st.toString());
+    }
+    tracer.trace("f");
+  }
+  return foo()
+      .toList() /// asyncStar: continued
+               ;
+}
+
+test2(Tracer tracer) {
+  var savedStackTrace;
+  foo() async
+              * /// asyncStar: continued
+               {
+    try {
+      tracer.trace("a");
+      throw "Error";
+    } catch (e, st) {
+      tracer.trace("b");
+      savedStackTrace = st;
+    }
+    tracer.trace("c");
+    await new Future.error("Error 2", savedStackTrace);
+    tracer.trace("d");
+  }
+  return foo()
+      .toList() /// asyncStar: continued
+      .catchError((e, st) {
+    tracer.trace("e");
+    Expect.equals(savedStackTrace.toString(), st.toString());
+  });
+}
+
+test3(Tracer tracer) {
+  var savedStackTrace;
+  foo() async
+              * /// asyncStar: continued
+                {
+    try {
+      tracer.trace("a");
+      throw "Error";
+    } catch (e, st) {
+      tracer.trace("b");
+      savedStackTrace = st;
+      rethrow;
+    }
+  }
+  return foo()
+      .toList() /// asyncStar: continued
+      .catchError((e, st) {
+    tracer.trace("c");
+    Expect.equals(savedStackTrace.toString(), st.toString());
+  });
+}
+
+runTest(String expectedTrace, Future test(Tracer tracer)) async {
+  Tracer tracer = new Tracer(expectedTrace);
+  await test(tracer);
+  tracer.done();
+}
+
+runTests() async {
+  await runTest("abcef", test1);
+  await runTest("abce", test2);
+  await runTest("abc", test3);
+}
+
+main() {
+  asyncTest(runTests);
+}