Remove unknown parameters in patched update

When updating a stack with the existing flag, we keep the parameters
from the old template to be used against the new version. Sometimes
parameters will get remove and won't make sense anymore, and keeping
them would break update with a 'Parameter was not defined' error. This
filters out such parameters so that the updates succeed.

Change-Id: I6f2aa77da28d271dd001a137bb574b5470292f15
Closes-Bug: #1558610

heat/engine/service.py

@@ -835,7 +835,7 @@ class EngineService(service.Service):
         # stack definition.  If PARAM_EXISTING is specified, we merge
         # any environment provided into the existing one and attempt
         # to use the existing stack template, if one is not provided.
-        if args.get(rpc_api.PARAM_EXISTING, None):
+        if args.get(rpc_api.PARAM_EXISTING):
             existing_env = current_stack.env.user_env_as_dict()
             existing_params = existing_env[env_fmt.PARAMETERS]
             clear_params = set(args.get(rpc_api.PARAM_CLEAR_PARAMETERS, []))
@@ -872,12 +872,14 @@ class EngineService(service.Service):
                                   'previous template stored'))
                     msg = _('PATCH update to non-COMPLETE stack')
                     raise exception.NotSupported(feature=msg)
+            tmpl = templatem.Template(new_template, files=new_files,
+                                      env=new_env)
+            for key in list(new_env.params.keys()):
+                if key not in tmpl.param_schemata():
+                    new_env.params.pop(key)
         else:
-            new_env = environment.Environment(params)
-            new_files = files
-            new_template = template
-
-        tmpl = templatem.Template(new_template, files=new_files, env=new_env)
+            tmpl = templatem.Template(template, files=files,
+                                      env=environment.Environment(params))
 
         max_resources = cfg.CONF.max_resources_per_stack
         if max_resources != -1 and len(tmpl[tmpl.RESOURCES]) > max_resources:

heat/tests/engine/service/test_stack_update.py

@@ -149,6 +149,7 @@ class ServiceStackUpdateTest(common.HeatTestCase):
         stk.set_stack_user_project_id('1234')
         self.assertEqual({'KeyName': 'test'}, stk.t.env.params)
 
+        t['parameters']['newparam'] = {'type': 'number'}
         with mock.patch('heat.engine.stack.Stack') as mock_stack:
             stk.update = mock.Mock()
             mock_stack.load.return_value = stk
@@ -187,6 +188,7 @@ class ServiceStackUpdateTest(common.HeatTestCase):
         self.assertEqual({'KeyName': 'test', 'removeme': 'foo'},
                          stk.t.env.params)
 
+        t['parameters']['newparam'] = {'type': 'number'}
         with mock.patch('heat.engine.stack.Stack') as mock_stack:
             stk.update = mock.Mock()
             mock_stack.load.return_value = stk

heat_integrationtests/functional/test_template_resource.py

@@ -935,3 +935,69 @@ resources:
             stack_identifier,
             self.main_template_update,
             files={'resource.yaml': self.nested_templ_update})
+
+
+class TemplateResourceRemovedParamTest(functional_base.FunctionalTestsBase):
+
+    main_template = '''
+heat_template_version: 2013-05-23
+parameters:
+  value1:
+    type: string
+    default: foo
+resources:
+  my_resource:
+    type: resource.yaml
+    properties:
+       value1: {get_param: value1}
+'''
+    nested_templ = '''
+heat_template_version: 2013-05-23
+parameters:
+  value1:
+    type: string
+    default: foo
+resources:
+  test:
+    type: OS::Heat::TestResource
+    properties:
+      value: {get_param: value1}
+'''
+    main_template_update = '''
+heat_template_version: 2013-05-23
+resources:
+  my_resource:
+    type: resource.yaml
+'''
+    nested_templ_update = '''
+heat_template_version: 2013-05-23
+parameters:
+  value1:
+    type: string
+    default: foo
+  value2:
+    type: string
+    default: bar
+resources:
+  test:
+    type: OS::Heat::TestResource
+    properties:
+      value:
+        str_replace:
+          template: VAL1-VAL2
+          params:
+            VAL1: {get_param: value1}
+            VAL2: {get_param: value2}
+'''
+
+    def test_update(self):
+        stack_identifier = self.stack_create(
+            template=self.main_template,
+            environment={'parameters': {'value1': 'spam'}},
+            files={'resource.yaml': self.nested_templ})
+
+        self.update_stack(
+            stack_identifier,
+            self.main_template_update,
+            environment={'parameter_defaults': {'value2': 'egg'}},
+            files={'resource.yaml': self.nested_templ_update}, existing=True)