Added a check for None value in get_object_display

When get_object_display returns None,
the concatenation of the list of display values fails.

Fixes bug 1030641

PATCH SET 2: Added function for joining of
lazy(proxy) strings(similar to string_concat)

Change-Id: I76398e85f93bc508aaae056aca77c8103998c7b6

horizon/tables/actions.py

@@ -25,7 +25,7 @@ from django.utils.translation import string_concat, ugettext_lazy as _
 
 from horizon import exceptions
 from horizon import messages
-from horizon.utils import html
+from horizon.utils import html, functions
 
 
 LOG = logging.getLogger(__name__)
@@ -497,7 +497,7 @@ class BatchAction(Action):
         action_not_allowed = []
         for datum_id in obj_ids:
             datum = table.get_object_by_id(datum_id)
-            datum_display = table.get_object_display(datum)
+            datum_display = table.get_object_display(datum) or _("N/A")
             if not table._filter_action(self, request, datum):
                 action_not_allowed.append(datum_display)
                 LOG.info('Permission denied to %s: "%s"' %
@@ -522,19 +522,19 @@ class BatchAction(Action):
         if action_not_allowed:
             msg = _('You do not have permission to %(action)s: %(objs)s')
             params = {"action": self._conjugate(action_not_allowed).lower(),
-                      "objs": ", ".join(action_not_allowed)}
+                      "objs": functions.lazy_join(", ", action_not_allowed)}
             messages.error(request, msg % params)
             success_message_level = messages.info
         if action_failure:
             msg = _('Unable to %(action)s: %(objs)s')
             params = {"action": self._conjugate(action_failure).lower(),
-                      "objs": ", ".join(action_failure)}
+                      "objs": functions.lazy_join(", ", action_failure)}
             messages.error(request, msg % params)
             success_message_level = messages.info
         if action_success:
             msg = _('%(action)s: %(objs)s')
             params = {"action": self._conjugate(action_success, True),
-                      "objs": ", ".join(action_success)}
+                      "objs": functions.lazy_join(", ", action_success)}
             success_message_level(request, msg % params)
 
         return shortcuts.redirect(self.get_success_url(request))

horizon/tests/table_tests.py

@@ -19,6 +19,8 @@ from django import shortcuts
 from django.core.urlresolvers import reverse
 from django.utils.translation import ugettext_lazy as _
 
+from mox import IsA
+
 from horizon import tables
 from horizon import test
 
@@ -654,3 +656,20 @@ class DataTableTests(test.TestCase):
         self.assertFalse(table.needs_form_wrapper)
         res = http.HttpResponse(table.render())
         self.assertNotContains(res, "<form")
+
+    def test_table_action_object_display_is_none(self):
+        action_string = "my_table__toggle__1"
+        req = self.factory.post('/my_url/', {'action': action_string})
+        self.table = MyTable(req, TEST_DATA)
+
+        self.mox.StubOutWithMock(self.table, 'get_object_display')
+        self.table.get_object_display(IsA(FakeObject)).AndReturn(None)
+        self.mox.ReplayAll()
+
+        self.assertEqual(self.table.parse_action(action_string),
+                         ('my_table', 'toggle', '1'))
+        handled = self.table.maybe_handle()
+        self.assertEqual(handled.status_code, 302)
+        self.assertEqual(handled["location"], "/my_url/")
+        self.assertEqual(list(req._messages)[0].message,
+                        u"Downed Item: N/A")

horizon/utils/functions.py

@@ -0,0 +1,9 @@
+from django.utils.encoding import force_unicode
+from django.utils.functional import lazy
+
+
+def _lazy_join(separator, strings):
+    return separator.join([force_unicode(s)
+                           for s in strings])
+
+lazy_join = lazy(_lazy_join, unicode)