=== modified file 'upstream/__init__.py'
--- upstream/__init__.py	2011-12-02 22:26:26 +0000
+++ upstream/__init__.py	2012-01-04 18:13:45 +0000
@@ -509,11 +509,11 @@
     # Debian style tarball
     m = re.match(packagename+"_(.*).orig", basename)
     if m:
-        return m.group(1)
+        return str(m.group(1))
     # Traditional, PACKAGE-VERSION.tar.gz
     m = re.match(packagename+"-(.*)", basename)
     if m:
-        return m.group(1)
+        return str(m.group(1))
     return None
 
 
@@ -534,7 +534,8 @@
     def get_latest_version(self, package, version):
         if self.version is not None:
             return self.version
-        return extract_tarball_version(self.path, package)
+        self.version = extract_tarball_version(self.path, package)
+        return self.version
 
 
 class LaunchpadReleaseFileSource(UpstreamSource):