=== modified file 'debian/changelog'
--- debian/changelog	2014-12-17 07:38:27 +0000
+++ debian/changelog	2015-01-08 08:10:34 +0000
@@ -78,6 +78,18 @@
 
  -- James Hunt <james.hunt@ubuntu.com>  Mon, 27 Oct 2014 16:03:42 +0000
 
+ubuntu-core-upgrader (0.1+ppa2) utopic; urgency=low
+
+  * rename the upgrader to ubuntu-core-upgrade
+
+ -- Michael Vogt <michael.vogt@ubuntu.com>  Wed, 22 Oct 2014 09:13:54 -0400
+
+ubuntu-core-upgrader (0.1+ppa1) utopic; urgency=low
+
+  * bump version number
+
+ -- Michael Vogt <michael.vogt@ubuntu.com>  Wed, 22 Oct 2014 09:03:15 -0400
+
 ubuntu-core-upgrader (0.1) utopic; urgency=medium
 
   * Initial release (LP: #1380674).

=== modified file 'ubuntucoreupgrader/upgrader.py'
--- ubuntucoreupgrader/upgrader.py	2014-12-12 15:51:58 +0000
+++ ubuntucoreupgrader/upgrader.py	2015-01-08 08:23:31 +0000
@@ -1628,9 +1628,14 @@
                 tar.list(verbose=True)
         else:
             log.debug('starting unpack')
-            tar.extractall(path=self.get_cache_dir(),
-                           members=self.tar_generator(tar))
-
+            # see bug #1408579, this forces tarfile to use tarinfo.gid
+            # instead of looking up the gid by local name which might
+            # be incorrect
+            from unittest.mock import patch
+            with patch("grp.getgrnam") as m:
+                m.side_effect = KeyError()
+                tar.extractall(path=self.get_cache_dir(),
+                               members=self.tar_generator(tar))
         tar.close()
 
         if self.upgrade_type == self.upgrade_types.UPGRADE_AB_PARTITIONS: