From b65b38db5cfc5dae169918b5c798228b420c264f Mon Sep 17 00:00:00 2001
From: rabi <ramishra@redhat.com>
Date: Thu, 4 Aug 2016 09:23:03 +0530
Subject: [PATCH] Add new environment section for merge strategies

This adds a new evironment section 'parameter_merge_strategies'.
These strategies would subsequently be used to merge parameters
and parameter_defaults from environment files.

Change-Id: Ib2b84ecdb2a1516ea0c5ced25a1fed408b954694
Blueprint: environment-merging
---
 heat/common/environment_format.py     |  8 +++++---
 heat/tests/test_environment_format.py | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/heat/common/environment_format.py b/heat/common/environment_format.py
index 2b11638343..1c4b968de0 100644
--- a/heat/common/environment_format.py
+++ b/heat/common/environment_format.py
@@ -17,10 +17,12 @@ from heat.common import template_format
 
 SECTIONS = (
     PARAMETERS, RESOURCE_REGISTRY, PARAMETER_DEFAULTS,
-    ENCRYPTED_PARAM_NAMES, EVENT_SINKS
+    ENCRYPTED_PARAM_NAMES, EVENT_SINKS,
+    PARAMETER_MERGE_STRATEGIES,
 ) = (
     'parameters', 'resource_registry', 'parameter_defaults',
-    'encrypted_param_names', 'event_sinks'
+    'encrypted_param_names', 'event_sinks',
+    'parameter_merge_strategies',
 )
 
 
@@ -63,7 +65,7 @@ def validate(env):
 def default_for_missing(env):
     """Checks a parsed environment for missing sections."""
     for param in SECTIONS:
-        if param not in env:
+        if param not in env and param != PARAMETER_MERGE_STRATEGIES:
             if param in (ENCRYPTED_PARAM_NAMES, EVENT_SINKS):
                 env[param] = []
             else:
diff --git a/heat/tests/test_environment_format.py b/heat/tests/test_environment_format.py
index 1af3cd8fcf..facc5d3a3e 100644
--- a/heat/tests/test_environment_format.py
+++ b/heat/tests/test_environment_format.py
@@ -34,6 +34,21 @@ resource_registry: {}
         tpl2 = environment_format.parse(yaml2)
         self.assertEqual(tpl1, tpl2)
 
+    def test_param_valid_strategy_section(self):
+        yaml1 = ''
+        yaml2 = '''
+parameters: {}
+encrypted_param_names: []
+parameter_defaults: {}
+parameter_merge_strategies: {}
+event_sinks: []
+resource_registry: {}
+'''
+        tpl1 = environment_format.parse(yaml1)
+        environment_format.default_for_missing(tpl1)
+        tpl2 = environment_format.parse(yaml2)
+        self.assertNotEqual(tpl1, tpl2)
+
     def test_wrong_sections(self):
         env = '''
 parameters: {}