gclient_eval: use ordered dict

This is a step towards implementing conditions.

Bug: 570091
Change-Id: I99467033082d96021854c23dcff3fc2b56f995b4
Reviewed-on: https://chromium-review.googlesource.com/517107
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Paweł Hajdan Jr. <phajdan.jr@chromium.org>

gclient_eval.py

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import ast
+import collections
 
 from third_party import schema
 
@@ -115,8 +116,9 @@ def _gclient_eval(node_or_string, global_scope, filename='<unknown>'):
     elif isinstance(node, ast.List):
       return list(map(_convert, node.elts))
     elif isinstance(node, ast.Dict):
-      return dict((_convert(k), _convert(v))
-                  for k, v in zip(node.keys, node.values))
+      return collections.OrderedDict(
+          (_convert(k), _convert(v))
+          for k, v in zip(node.keys, node.values))
     elif isinstance(node, ast.Name):
       if node.id not in _allowed_names:
         raise ValueError(

tests/gclient_eval_unittest.py

@@ -3,6 +3,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import itertools
 import logging
 import os
 import sys
@@ -58,6 +59,13 @@ class GClientEvalTest(unittest.TestCase):
     self.assertIn(
         'unexpected AST node: <_ast.ListComp object', str(cm.exception))
 
+  def test_dict_ordered(self):
+    for test_case in itertools.permutations(range(4)):
+      input_data = ['{'] + ['"%s": "%s",' % (n, n) for n in test_case] + ['}']
+      expected = [(str(n), str(n)) for n in test_case]
+      result = gclient_eval._gclient_eval(''.join(input_data), {})
+      self.assertEqual(expected, result.items())
+
 
 class GClientExecTest(unittest.TestCase):
   def test_basic(self):