From b1e320ea6635daf3ba2bd0f83dbb808d2bc8c0d9 Mon Sep 17 00:00:00 2001
From: Rabi Mishra <ramishra@redhat.com>
Date: Mon, 25 Jan 2016 17:11:50 +0530
Subject: [PATCH] Remove implementation_signature check

Remove the unnecessary checking of implementation signature of
current resource with the prev_resource in needs_update.
It seems prev_resource is always resource from the backup_stack
and there would be no difference.

If there is a change of implementation class, it would have been
already handled[1]

[1]
https://github.com/openstack/heat/blob/master/heat/engine/update.py#L139-L140

Change-Id: I1df84986cbc4bae7bcdbaae8b5aacbfa7adaec32
---
 heat/engine/resource.py                    | 18 ------------------
 heat/engine/resources/stack_resource.py    | 11 -----------
 heat/engine/resources/template_resource.py |  4 ----
 heat/tests/test_stack_resource.py          | 15 ---------------
 4 files changed, 48 deletions(-)

diff --git a/heat/engine/resource.py b/heat/engine/resource.py
index 24d67b490..75c1cded2 100644
--- a/heat/engine/resource.py
+++ b/heat/engine/resource.py
@@ -427,15 +427,6 @@ class Resource(object):
         else:
             return ri.name == resource_type
 
-    def implementation_signature(self):
-        """Return a tuple defining the implementation.
-
-        This should be broken down into a definition and an
-        implementation version.
-        """
-
-        return (self.__class__.__name__, self.support_status.version)
-
     def identifier(self):
         """Return an identifier for this resource."""
         return identifier.ResourceIdentifier(resource_name=self.name,
@@ -865,15 +856,6 @@ class Resource(object):
                                     and self.status == self.COMPLETE):
             raise exception.UpdateReplace(self)
 
-        if prev_resource is not None:
-            cur_class_def, cur_ver = self.implementation_signature()
-            prev_class_def, prev_ver = prev_resource.implementation_signature()
-
-            if prev_class_def != cur_class_def:
-                raise exception.UpdateReplace(self.name)
-            if prev_ver != cur_ver:
-                return True
-
         if before != after.freeze():
             return True
 
diff --git a/heat/engine/resources/stack_resource.py b/heat/engine/resources/stack_resource.py
index 06455e9de..403972442 100644
--- a/heat/engine/resources/stack_resource.py
+++ b/heat/engine/resources/stack_resource.py
@@ -11,12 +11,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import hashlib
 import json
 
 from oslo_config import cfg
 from oslo_log import log as logging
-from oslo_serialization import jsonutils
 from oslo_utils import excutils
 import six
 
@@ -530,12 +528,3 @@ class StackResource(resource.Resource):
 
     def _resolve_attribute(self, name):
         return self.get_output(name)
-
-    def implementation_signature(self):
-        schema_names = ([prop for prop in self.properties_schema] +
-                        [at for at in self.attributes_schema])
-        schema_hash = hashlib.sha256(';'.join(schema_names))
-        definition = {'template': self.child_template(),
-                      'files': self.stack.t.files}
-        definition_hash = hashlib.sha256(jsonutils.dumps(definition))
-        return (schema_hash.hexdigest(), definition_hash.hexdigest())
diff --git a/heat/engine/resources/template_resource.py b/heat/engine/resources/template_resource.py
index d785fc86a..d4206e07b 100644
--- a/heat/engine/resources/template_resource.py
+++ b/heat/engine/resources/template_resource.py
@@ -178,10 +178,6 @@ class TemplateResource(stack_resource.StackResource):
         self._get_resource_info(definition)
         self._generate_schema(definition)
 
-    def implementation_signature(self):
-        self._generate_schema(self.t)
-        return super(TemplateResource, self).implementation_signature()
-
     def template_data(self):
         # we want to have the latest possible template.
         # 1. look in files
diff --git a/heat/tests/test_stack_resource.py b/heat/tests/test_stack_resource.py
index e1c8e8533..b6c9c3172 100644
--- a/heat/tests/test_stack_resource.py
+++ b/heat/tests/test_stack_resource.py
@@ -19,7 +19,6 @@ from oslo_config import cfg
 from oslo_messaging import exceptions as msg_exceptions
 from oslo_serialization import jsonutils
 import six
-import testtools
 
 from heat.common import exception
 from heat.common import template_format
@@ -207,20 +206,6 @@ class StackResourceTest(StackResourceBaseTest):
 
         self.assertEqual(0, delete_nested.call_count)
 
-    @testtools.skipIf(six.PY3, "needs a separate change")
-    def test_implementation_signature(self):
-        self.parent_resource.child_template = mock.Mock(
-            return_value=self.simple_template)
-        sig1, sig2 = self.parent_resource.implementation_signature()
-        self.assertEqual('7b0eaabb5b82b9e90804d42e0bb739035588cb797'
-                         '82427770646686ca2235028', sig1)
-        self.assertEqual('8fa647d036b8f36909386e1e1004539dfae7a8e88'
-                         'c24aac0d85399e881421301', sig2)
-        self.parent_stack.t.files["foo"] = "bar"
-        sig1a, sig2a = self.parent_resource.implementation_signature()
-        self.assertEqual(sig1, sig1a)
-        self.assertNotEqual(sig2, sig2a)
-
     def test_propagated_files(self):
         """Test passing of the files map in the top level to the child.