Make Future.wait have an eagerError option that defaults to false.

tests/lib/async/futures_test.dart

 // Copyright (c) 2011, 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.
 
 library futures_test;
 import 'package:async_helper/async_helper.dart';
 import "package:expect/expect.dart";
 import 'dart:async';
 
 Future testWaitEmpty() {
@@ skipping 58 matching lines @@
   c2.completeError('incorrect error 1');
 
   return Future.wait(futures).then((_) {
     throw 'incorrect error 2';
   }).catchError((error, stackTrace) {
     Expect.equals('correct error', error);
     Expect.isNull(stackTrace);
   });
 }
 
+Future testWaitWithMultipleErrorsEager() {
+  List<Future> futures = new List<Future>();
+  Completer c1 = new Completer();
+  Completer c2 = new Completer();
+  futures.add(c1.future);
+  futures.add(c2.future);
+  c1.completeError('correct error');
+  c2.completeError('incorrect error 1');
+
+  return Future.wait(futures, eagerError: true).then((_) {
+    throw 'incorrect error 2';
+  }).catchError((error, stackTrace) {
+    Expect.equals('correct error', error);
+    Expect.isNull(stackTrace);
+  });
+}
+
 StackTrace get currentStackTrace {
   try {
     throw 0;
   } catch(e, st) {
     return st;
   }
   return null;
 }
 
 Future testWaitWithSingleErrorWithStackTrace() {
@@ skipping 23 matching lines @@
   c2.completeError('incorrect error 1');
 
   return Future.wait(futures).then((_) {
     throw 'incorrect error 2';
   }).catchError((error, stackTrace) {
     Expect.equals('correct error', error);
     Expect.isNotNull(stackTrace);
   });
 }
 
+Future testWaitWithMultipleErrorsWithStackTraceEager() {
+  List<Future> futures = new List<Future>();
+  Completer c1 = new Completer();
+  Completer c2 = new Completer();
+  futures.add(c1.future);
+  futures.add(c2.future);
+  c1.completeError('correct error', currentStackTrace);
+  c2.completeError('incorrect error 1');
+
+  return Future.wait(futures, eagerError: true).then((_) {
+    throw 'incorrect error 2';
+  }).catchError((error, stackTrace) {
+    Expect.equals('correct error', error);
+    Expect.isNotNull(stackTrace);
+  });
+}
+
+Future testEagerWait() {
+  var st;
+  try { throw 0; } catch (e, s) { st = s; }
+  Completer c1 = new Completer();
+  Completer c2 = new Completer();
+  List<Future> futures = <Future>[c1.future, c2.future];
+  Future waited = Future.wait(futures, eagerError: true);
+  var result = waited.then((v) { throw "should not be called"; },
+                           onError: (e, s) {
+                             Expect.equals(e, 42);
+                             Expect.identical(st, s);
+                             return true;
+                           });
+  c1.completeError(42, st);
+  return result;
+}
+
 Future testForEachEmpty() {
   return Future.forEach([], (_) {
     throw 'should not be called';
   });
 }
 
 Future testForEach() {
   var seen = <int>[];
   return Future.forEach([1, 2, 3, 4, 5], (n) {
     seen.add(n);
@@ skipping 16 matching lines @@
 
 main() {
   List<Future> futures = new List<Future>();
 
   futures.add(testWaitEmpty());
   futures.add(testCompleteAfterWait());
   futures.add(testCompleteBeforeWait());
   futures.add(testWaitWithMultipleValues());
   futures.add(testWaitWithSingleError());
   futures.add(testWaitWithMultipleErrors());
+  futures.add(testWaitWithMultipleErrorsEager());
   futures.add(testWaitWithSingleErrorWithStackTrace());
   futures.add(testWaitWithMultipleErrorsWithStackTrace());
+  futures.add(testWaitWithMultipleErrorsWithStackTraceEager());
+  futures.add(testEagerWait());
   futures.add(testForEachEmpty());
   futures.add(testForEach());
   futures.add(testForEachWithException());
 
   asyncStart();
   Future.wait(futures).then((List list) {
-    Expect.equals(11, list.length);
+    Expect.equals(14, list.length);
     asyncEnd();
   });
 }