Ensure that YAML maps' map keys are order-independent.

pkg/yaml/lib/src/utils.dart

 // Copyright (c) 2013, 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 yaml.utils;
 
 import 'package:collection/collection.dart';
 
 /// Returns a hash code for [obj] such that structurally equivalent objects
 /// will have the same hash code.
 ///
 /// This supports deep equality for maps and lists, including those with
 /// self-referential structures.
 int hashCodeFor(obj) {
   var parents = [];
 
   _hashCodeFor(value) {
     if (parents.any((parent) => identical(parent, value))) return -1;
 
     parents.add(value);
     try {
       if (value is Map) {
-        return _hashCodeFor(value.keys) ^ _hashCodeFor(value.values);
+        var equality = const SetEquality();

[Jennifer Messerly, 2014/05/20 22:51:25]

maybe use UnorderedIterableEquality and avoid the toSet call?

[nweiz, 2014/05/20 22:58:54]

Oh, I missed that, good idea.

+        return equality.hash(value.keys.map(_hashCodeFor).toSet()) ^
+            equality.hash(value.values.map(_hashCodeFor).toSet());
       } else if (value is Iterable) {
         return const IterableEquality().hash(value.map(hashCodeFor));
       }
       return value.hashCode;
     } finally {
       parents.removeLast();
     }
   }
 
   return _hashCodeFor(obj);
 }