apt/cache.py: Fix Cache.update() to not raise errors on successful updates.

1 files changed, 6 insertions, 5 deletions

diff --git a/apt/cache.py b/apt/cache.py
index 2f097f6b..2a62ddce 100644
--- a/apt/cache.py
+++ b/apt/cache.py
@@ -307,11 +307,12 @@ class Cache(object):
         try:
             if fetch_progress is None:
                 fetch_progress = apt.progress.FetchProgress()
-            res = self._cache.update(fetch_progress, self._list,
-                                      pulse_interval)
-            if res == apt_pkg.Acquire.RESULT_CANCELLED and raise_on_error:
-                raise FetchCancelledException()
-            if res == apt_pkg.Acquire.RESULT_FAILED and raise_on_error:
+            try:
+                res = self._cache.update(fetch_progress, self._list,
+                                         pulse_interval)
+            except SystemError, e:
+                raise FetchFailedException(e)
+            if not res and raise_on_error:
                 raise FetchFailedException()
             else:
                 return res