Don't override sections in deep_updatepike-em1.11.2

When you comment all the elements in a YAML mapping, you end up with
None instead of an empty mapping, which can have bad side effect when
handling multiple environemnents. Let's handle that by ignoring the
latest None value.

Change-Id: I77ffabeb8d4cd2886ef4f41351e42ebe487b5d4b
(cherry picked from commit 2a8ce0d0656f47331a164163f9e3b302de4d3c88)

2 files changed, 48 insertions, 0 deletions

diff --git a/heatclient/common/template_utils.py b/heatclient/common/template_utils.py
index 9e9c85b..b38710b 100644
--- a/heatclient/common/template_utils.py
+++ b/heatclient/common/template_utils.py
@@ -198,6 +198,9 @@ def deep_update(old, new):
         if isinstance(v, collections.Mapping):
             r = deep_update(old.get(k, {}), v)
             old[k] = r
+        elif v is None and isinstance(old.get(k), collections.Mapping):
+            # Don't override empty data, to work around yaml syntax issue
+            pass
         else:
             old[k] = new[k]
     return old
diff --git a/heatclient/tests/unit/test_template_utils.py b/heatclient/tests/unit/test_template_utils.py
index a48e0b3..01cfa13 100644
--- a/heatclient/tests/unit/test_template_utils.py
+++ b/heatclient/tests/unit/test_template_utils.py
@@ -448,6 +448,51 @@ class ShellEnvironmentTest(testtools.TestCase):
 
         ])
 
+    @mock.patch('six.moves.urllib.request.urlopen')
+    def test_process_multiple_environments_empty_registry(self, mock_url):
+        # Setup
+        env_file1 = '/home/my/dir/env1.yaml'
+        env_file2 = '/home/my/dir/env2.yaml'
+
+        env1 = b'''
+        resource_registry:
+          "OS::Thingy1": "file:///home/b/a.yaml"
+        '''
+        env2 = b'''
+        resource_registry:
+        '''
+        mock_url.side_effect = [six.BytesIO(env1),
+                                six.BytesIO(self.template_a),
+                                six.BytesIO(self.template_a),
+                                six.BytesIO(env2)]
+
+        # Test
+        env_file_list = []
+        files, env = template_utils.process_multiple_environments_and_files(
+            [env_file1, env_file2], env_list_tracker=env_file_list)
+
+        # Verify
+        expected_env = {
+            'resource_registry': {'OS::Thingy1': 'file:///home/b/a.yaml'}}
+        self.assertEqual(expected_env, env)
+
+        self.assertEqual(self.template_a.decode('utf-8'),
+                         files['file:///home/b/a.yaml'])
+
+        self.assertEqual(['file:///home/my/dir/env1.yaml',
+                          'file:///home/my/dir/env2.yaml'], env_file_list)
+        self.assertIn('file:///home/my/dir/env1.yaml', files)
+        self.assertIn('file:///home/my/dir/env2.yaml', files)
+        self.assertEqual(expected_env,
+                         json.loads(files['file:///home/my/dir/env1.yaml']))
+        mock_url.assert_has_calls([
+            mock.call('file://%s' % env_file1),
+            mock.call('file:///home/b/a.yaml'),
+            mock.call('file:///home/b/a.yaml'),
+            mock.call('file://%s' % env_file2),
+
+        ])
+
     def test_global_files(self):
         url = 'file:///home/b/a.yaml'
         env = '''