Get rid of unneeded Future.immediate() calls.

utils/pub/validator.dart

 // Copyright (c) 2012, 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 validator;
 
 import 'dart:async';
 
 import 'entrypoint.dart';
 import 'log.dart' as log;
@@ skipping 35 matching lines @@
       Entrypoint entrypoint) {
     var validators = [
       new LibValidator(entrypoint),
       new LicenseValidator(entrypoint),
       new NameValidator(entrypoint),
       new PubspecFieldValidator(entrypoint),
       new DependencyValidator(entrypoint),
       new DirectoryValidator(entrypoint)
     ];
 
-    // TODO(nweiz): The sleep 0 here forces us to go async. This works around
-    // 3356, which causes a bug if all validators are (synchronously) using
-    // Future.immediate and an error is thrown before a handler is set up.
-    return sleep(0).then((_) {
-      return Future.wait(
-          validators.mappedBy((validator) => validator.validate()));
-    }).then((_) {
+    return Future.wait(validators.mappedBy((validator) => validator.validate()))
+      .then((_) {
       var errors =
           flatten(validators.mappedBy((validator) => validator.errors));
       var warnings =
           flatten(validators.mappedBy((validator) => validator.warnings));
 
       if (!errors.isEmpty) {
         log.error("Missing requirements:");
         for (var error in errors) {
           log.error("* ${Strings.join(error.split('\n'), '\n  ')}");
         }
         log.error("");
       }
 
       if (!warnings.isEmpty) {
         log.warning("Suggestions:");
         for (var warning in warnings) {
           log.warning("* ${Strings.join(warning.split('\n'), '\n  ')}");
         }
         log.warning("");
       }
 
       return new Pair<List<String>, List<String>>(errors, warnings);
     });
   }
 }