Make the objects behave more consistently

1. don't return DB models from the objects API
   (only return Objects)
2. delete shouldn't return anything
3. update_and_save should return the refreshed object.

Note: there is still some inconsistency in what is returned by
update_by_id() some return an object and some return a bool.

Related-bug: #1432936
Change-Id: I1a0a38773d4fc4a62af5e0a98076396f39187b6c

heat/objects/raw_template.py

@@ -69,8 +69,7 @@ class RawTemplate(
     @classmethod
     def get_by_id(cls, context, template_id):
         raw_template_db = db_api.raw_template_get(context, template_id)
-        raw_template = cls._from_db_object(context, cls(), raw_template_db)
-        return raw_template
+        return cls._from_db_object(context, cls(), raw_template_db)
 
     @classmethod
     def encrypt_hidden_parameters(cls, tmpl):
@@ -85,12 +84,15 @@ class RawTemplate(
 
     @classmethod
     def create(cls, context, values):
-        return db_api.raw_template_create(context, values)
+        return cls._from_db_object(context, cls(),
+                                   db_api.raw_template_create(context, values))
 
     @classmethod
     def update_by_id(cls, context, template_id, values):
-        return db_api.raw_template_update(context, template_id, values)
+        return cls._from_db_object(
+            context, cls(),
+            db_api.raw_template_update(context, template_id, values))
 
     @classmethod
     def delete(cls, context, template_id):
-        return db_api.raw_template_delete(context, template_id)
+        db_api.raw_template_delete(context, template_id)

heat/objects/resource.py

@@ -99,8 +99,7 @@ class Resource(
     @classmethod
     def get_obj(cls, context, resource_id):
         resource_db = db_api.resource_get(context, resource_id)
-        resource = cls._from_db_object(cls(context), context, resource_db)
-        return resource
+        return cls._from_db_object(cls(context), context, resource_db)
 
     @classmethod
     def get_all(cls, context):
@@ -116,7 +115,8 @@ class Resource(
 
     @classmethod
     def create(cls, context, values):
-        return db_api.resource_create(context, values)
+        return cls._from_db_object(cls(context), context,
+                                   db_api.resource_create(context, values))
 
     @classmethod
     def delete(cls, context, resource_id):
@@ -148,22 +148,19 @@ class Resource(
             context,
             resource_name,
             stack_id)
-        resource = cls._from_db_object(cls(context), context, resource_db)
-        return resource
+        return cls._from_db_object(cls(context), context, resource_db)
 
     @classmethod
     def get_by_physical_resource_id(cls, context, physical_resource_id):
         resource_db = db_api.resource_get_by_physical_resource_id(
             context,
             physical_resource_id)
-        resource = cls._from_db_object(cls(context), context, resource_db)
-        return resource
+        return cls._from_db_object(cls(context), context, resource_db)
 
     def update_and_save(self, values):
         resource_db = db_api.resource_get(self._context, self.id)
         resource_db.update_and_save(values)
-        self._refresh()
-        return resource_db
+        return self._refresh()
 
     def _refresh(self):
         return self.__class__._from_db_object(

heat/objects/resource_data.py

@@ -80,4 +80,4 @@ class ResourceData(
 
     @classmethod
     def delete(cls, resource, key):
-        return db_api.resource_data_delete(resource, key)
+        db_api.resource_data_delete(resource, key)

heat/objects/service.py

@@ -75,7 +75,7 @@ class Service(base.VersionedObject,
 
     @classmethod
     def delete(cls, context, service_id, soft_delete=True):
-        return db_api.service_delete(context, service_id, soft_delete)
+        db_api.service_delete(context, service_id, soft_delete)
 
     @classmethod
     def get_all(cls, context):

heat/objects/software_deployment.py

@@ -79,6 +79,10 @@ class SoftwareDeployment(base.VersionedObject,
 
     @classmethod
     def update_by_id(cls, context, deployment_id, values):
+        """Note this is a bit unusual as it returns the object.
+
+        Other update_by_id methods return a bool (was it updated).
+        """
         return cls._from_db_object(
             context, cls(),
             db_api.software_deployment_update(context, deployment_id, values))

heat/objects/stack.py

@@ -20,7 +20,8 @@ Stack object
 from oslo_versionedobjects import base
 from oslo_versionedobjects import fields
 
-
+from heat.common import exception
+from heat.common.i18n import _
 from heat.db import api as db_api
 from heat.objects import fields as heat_fields
 from heat.objects import raw_template
@@ -88,7 +89,7 @@ class Stack(
     def get_by_id(cls, context, stack_id, **kwargs):
         db_stack = db_api.stack_get(context, stack_id, **kwargs)
         if not db_stack:
-            return db_stack
+            return None
         stack = cls._from_db_object(context, cls(context), db_stack)
         return stack
 
@@ -100,7 +101,7 @@ class Stack(
             owner_id
         )
         if not db_stack:
-            return db_stack
+            return None
         stack = cls._from_db_object(context, cls(context), db_stack)
         return stack
 
@@ -108,7 +109,7 @@ class Stack(
     def get_by_name(cls, context, stack_name):
         db_stack = db_api.stack_get_by_name(context, stack_name)
         if not db_stack:
-            return db_stack
+            return None
         stack = cls._from_db_object(context, cls(context), db_stack)
         return stack
 
@@ -144,20 +145,33 @@ class Stack(
 
     @classmethod
     def create(cls, context, values):
-        return db_api.stack_create(context, values)
+        return cls._from_db_object(context, cls(context),
+                                   db_api.stack_create(context, values))
 
     @classmethod
     def update_by_id(cls, context, stack_id, values):
+        """Update and return (boolean) if it was updated.
+
+        Note: the underlying stack_update filters by current_traversal
+        and stack_id.
+        """
         return db_api.stack_update(context, stack_id, values)
 
     @classmethod
     def delete(cls, context, stack_id):
-        return db_api.stack_delete(context, stack_id)
+        db_api.stack_delete(context, stack_id)
 
     def update_and_save(self, values):
-        db_stack = self.__class__.update_by_id(self._context, self.id, values)
-        self.refresh()
-        return db_stack
+        has_updated = self.__class__.update_by_id(self._context,
+                                                  self.id, values)
+        if not has_updated:
+            raise exception.NotFound(_('Attempt to update a stack with id: '
+                                       '%(id)s %(traversal) %(msg)s') % {
+                                           'id': self.id,
+                                           'traversal': self.current_traversal,
+                                           'msg': 'that does not exist'})
+
+        return self.refresh()
 
     def __eq__(self, another):
         self.refresh()  # to make test object comparison work well

heat/objects/user_creds.py

@@ -64,7 +64,7 @@ class UserCreds(base.VersionedObject,
 
     @classmethod
     def delete(cls, context, user_creds_id):
-        return db_api.user_creds_delete(context, user_creds_id)
+        db_api.user_creds_delete(context, user_creds_id)
 
     @classmethod
     def get_by_id(cls, context_id):