Fix parameter merging with merge strategies

Earlier users had to specify merge strategy for
a parameter/parameter_default in every environment
file where they are used(or the defaults for that
environment was used). However, the strategy
for a parameter in the first environment was
ignored as there is nothing to merge.

With Iec3367667248d0b46196a6d569f3cbb3b200d842, we
changed to use existing merge strategies, but the
strategies in the first environment were still
ignored. This patch fixes it.

Task: 45578
Change-Id: Ic6125c6af60c1007243523cc8510a17f49c7b5af
(cherry picked from commit d9fe7301b3af2db9fa56d59eb405add94730ba50)
(cherry picked from commit 154691d21d24351edbe066fd23c731afad456b85)

2 files changed, 16 insertions, 15 deletions

diff --git a/heat/common/environment_util.py b/heat/common/environment_util.py
index eb3b8cde1..490802830 100644
--- a/heat/common/environment_util.py
+++ b/heat/common/environment_util.py
@@ -113,24 +113,26 @@ def merge_parameters(old, new, param_schemata, strategies_in_file,
             raise exception.InvalidMergeStrategyForParam(strategy=MERGE,
                                                          param=p_key)
 
-    new_strategies = {}
-
-    if not old:
-        return new, new_strategies
-
     for key, value in new.items():
         # if key not in param_schemata ignore it
         if key in param_schemata and value is not None:
             param_merge_strategy = get_param_merge_strategy(
                 strategies_in_file, key, available_strategies)
             if key not in available_strategies:
-                new_strategies[key] = param_merge_strategy
+                available_strategies[key] = param_merge_strategy
 
             elif param_merge_strategy != available_strategies[key]:
                 raise exception.ConflictingMergeStrategyForParam(
                     strategy=param_merge_strategy,
                     param=key, env_file=env_file)
 
+    if not old:
+        return new
+
+    for key, value in new.items():
+        # if key not in param_schemata ignore it
+        if key in param_schemata and value is not None:
+            param_merge_strategy = available_strategies[key]
             if param_merge_strategy == DEEP_MERGE:
                 LOG.debug("Deep Merging Parameter: %s", key)
                 param_merge(key, value,
@@ -143,7 +145,7 @@ def merge_parameters(old, new, param_schemata, strategies_in_file,
                 LOG.debug("Overriding Parameter: %s", key)
                 old[key] = value
 
-    return old, new_strategies
+    return old
 
 
 def merge_environments(environment_files, files,
@@ -181,11 +183,10 @@ def merge_environments(environment_files, files,
             if section_value:
                 if section_key in (env_fmt.PARAMETERS,
                                    env_fmt.PARAMETER_DEFAULTS):
-                    params[section_key], new_strategies = merge_parameters(
+                    params[section_key] = merge_parameters(
                         params[section_key], section_value,
                         param_schemata, strategies_in_file,
                         available_strategies, filename)
-                    available_strategies.update(new_strategies)
                 else:
                     params[section_key] = merge_map(params[section_key],
                                                     section_value)
diff --git a/heat/tests/test_common_env_util.py b/heat/tests/test_common_env_util.py
index fca3a9b34..07e077098 100644
--- a/heat/tests/test_common_env_util.py
+++ b/heat/tests/test_common_env_util.py
@@ -135,7 +135,7 @@ class TestMergeEnvironments(common.HeatTestCase):
 
     def test_merge_envs_with_specified_default(self):
         merge_strategies = {'default': 'deep_merge'}
-        self.env_2['parameter_merge_strategies'] = merge_strategies
+        self.env_1['parameter_merge_strategies'] = merge_strategies
         files = {'env_1': json.dumps(self.env_1),
                  'env_2': json.dumps(self.env_2)}
         environment_files = ['env_1', 'env_2']
@@ -169,7 +169,7 @@ class TestMergeEnvironments(common.HeatTestCase):
             'lst_value2': 'merge',
             'json_value1': 'deep_merge'}
 
-        self.env_2['parameter_merge_strategies'] = merge_strategies
+        self.env_1['parameter_merge_strategies'] = merge_strategies
 
         files = {'env_1': json.dumps(self.env_1),
                  'env_2': json.dumps(self.env_2)}
@@ -207,7 +207,7 @@ class TestMergeEnvironments(common.HeatTestCase):
             'lst_value1': "deep_merge",
             'json_value1': "merge"}
 
-        self.env_2['parameter_merge_strategies'] = merge_strategies
+        self.env_1['parameter_merge_strategies'] = merge_strategies
         self.env_3['parameter_merge_strategies'] = env3_merge_strategies
 
         files = {'env_1': json.dumps(self.env_1),
@@ -231,7 +231,7 @@ class TestMergeEnvironments(common.HeatTestCase):
             'default': "overwrite",
             'lst_value2': "overwrite"}
 
-        self.env_2['parameter_merge_strategies'] = merge_strategies
+        self.env_1['parameter_merge_strategies'] = merge_strategies
         self.env_4['parameter_merge_strategies'] = env4_merge_strategies
 
         files = {'env_1': json.dumps(self.env_1),
@@ -275,9 +275,9 @@ class TestMergeEnvironments(common.HeatTestCase):
         self.assertEqual({'value1': 0}, self.params['parameter_defaults'])
 
     def test_merge_envs_with_zeros_in_maps(self):
-        env1 = {'parameter_defaults': {'value1': {'foo': 1}}}
-        env2 = {'parameter_defaults': {'value1': {'foo': 0}},
+        env1 = {'parameter_defaults': {'value1': {'foo': 1}},
                 'parameter_merge_strategies': {'value1': 'deep_merge'}}
+        env2 = {'parameter_defaults': {'value1': {'foo': 0}}}
         files = {'env_1': json.dumps(env1),
                  'env_2': json.dumps(env2)}
         environment_files = ['env_1', 'env_2']