Fix bug Swift ACL which disappears on Glance v1 images

Currently, when we make an update on a public image, Swift ACL disappears.
This patch allows to avoid the ACL update if there is no change to the
is_public_attribute.
If an update is made on a Glance image without changing the public attribute
or location, then the function which modifies ACLS is not called, in order
to keep ACLS.

Closes-Bug: 1584076

Change-Id: I21e9deb9105faee87500998eff47c6faa1d02914
(cherry picked from commit d719b3a164)

glance/api/v1/images.py

@@ -1008,8 +1008,9 @@ class Controller(controller.BaseController):
         orig_or_updated_loc = location or orig_image_meta.get('location')
         if orig_or_updated_loc:
             try:
-                self.update_store_acls(req, id, orig_or_updated_loc,
-                                       public=is_public)
+                if is_public is not None or location is not None:
+                    self.update_store_acls(req, id, orig_or_updated_loc,
+                                           public=is_public)
             except store.BadStoreUri:
                 msg = _("Invalid location: %s") % location
                 LOG.warn(msg)

glance/tests/unit/v1/test_api.py

@@ -2262,6 +2262,22 @@ class TestGlanceAPI(base.IsolatedUnitTest):
         res = req.get_response(self.api)
         self.assertEqual(200, res.status_int)
 
+    @mock.patch.object(registry, 'update_image_metadata')
+    def test_update_without_public_attribute(self, mock_update_image_metadata):
+        req = webob.Request.blank("/images/%s" % UUID1)
+        req.context = self.context
+        image_meta = {'properties': {}}
+        image_controller = glance.api.v1.images.Controller()
+
+        with mock.patch.object(
+            image_controller, 'update_store_acls'
+        ) as mock_update_store_acls:
+            mock_update_store_acls.return_value = None
+            mock_update_image_metadata.return_value = {}
+            image_controller.update(
+                req, UUID1, image_meta, None)
+            self.assertEqual(0, mock_update_store_acls.call_count)
+
     def test_add_image_wrong_content_type(self):
         fixture_headers = {
             'x-image-meta-name': 'fake image #3',