From 842e6cc31da7e060aba9409a91bd46149223d61e Mon Sep 17 00:00:00 2001
From: Steve Baker <sbaker@redhat.com>
Date: Thu, 6 Dec 2012 11:53:45 +1300
Subject: [PATCH] Resource.__eq__ allow resources in different stacks

Doing a stack update was incorrectly replacing identical resources
because Refs in the new resource were evaluating to None in the new stack.

This change allows an alternative template to be passed to parsed_template
and modifies __eq__ to compare the two templates in the same stack.

__eq__ now also checks that the name of both resources matches, since a stack
could have multiple identical resources with different names.

Change-Id: I7e09ee1238dd01490cdfe186c51b7fada9546a63
---
 heat/engine/resource.py     | 10 ++++++----
 heat/tests/test_resource.py | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/heat/engine/resource.py b/heat/engine/resource.py
index c3b149b4..fad416eb 100644
--- a/heat/engine/resource.py
+++ b/heat/engine/resource.py
@@ -136,9 +136,11 @@ class Resource(object):
     def __eq__(self, other):
         '''Allow == comparison of two resources'''
         # For the purposes of comparison, we declare two resource objects
-        # equal if their parsed_templates are the same
+        # equal if their names and parsed_templates are the same
         if isinstance(other, Resource):
-            return self.parsed_template() == other.parsed_template()
+            return (self.name == other.name) and (
+                self.parsed_template() == self.parsed_template(
+                    template=other.t))
         return NotImplemented
 
     def __ne__(self, other):
@@ -156,14 +158,14 @@ class Resource(object):
         return identifier.ResourceIdentifier(resource_name=self.name,
                                              **self.stack.identifier())
 
-    def parsed_template(self, section=None, default={}):
+    def parsed_template(self, section=None, default={}, template=None):
         '''
         Return the parsed template data for the resource. May be limited to
         only one section of the data, in which case a default value may also
         be supplied.
         '''
         if section is None:
-            template = self.t
+            template = template or self.t
         else:
             template = self.t.get(section, default)
         return self.stack.resolve_runtime_data(template)
diff --git a/heat/tests/test_resource.py b/heat/tests/test_resource.py
index cf0f4ae9..3eeadf30 100644
--- a/heat/tests/test_resource.py
+++ b/heat/tests/test_resource.py
@@ -95,6 +95,27 @@ class ResourceTest(unittest.TestCase):
         res = resource.GenericResource('test_resource', tmpl, self.stack)
         self.assertEqual(res.metadata, {})
 
+    def test_equals_different_stacks(self):
+        tmpl1 = {'Type': 'Foo'}
+        tmpl2 = {'Type': 'Foo'}
+        tmpl3 = {'Type': 'Bar'}
+        stack2 = parser.Stack(None, 'test_stack', parser.Template({}),
+                                  stack_id=-1)
+        res1 = resource.GenericResource('test_resource', tmpl1, self.stack)
+        res2 = resource.GenericResource('test_resource', tmpl2, stack2)
+        res3 = resource.GenericResource('test_resource2', tmpl3, stack2)
+
+        self.assertEqual(res1, res2)
+        self.assertNotEqual(res1, res3)
+
+    def test_equals_names(self):
+        tmpl1 = {'Type': 'Foo'}
+        tmpl2 = {'Type': 'Foo'}
+        res1 = resource.GenericResource('test_resource1', tmpl1, self.stack)
+        res2 = resource.GenericResource('test_resource2', tmpl2, self.stack)
+
+        self.assertNotEqual(res1, res2)
+
 
 @attr(tag=['unit', 'resource'])
 @attr(speed='fast')
-- 
2.45.2