Make git auto-svn fail if git svn fetch fails.

git_common.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Monkeypatch IMapIterator so that Ctrl-C can kill everything properly.
 # Derived from https://gist.github.com/aljungberg/626518
 import multiprocessing.pool
 from multiprocessing.pool import IMapIterator
 def wrapper(func):
   def wrap(self, timeout=None):
@@ skipping 547 matching lines @@
   stderr is dropped to avoid races if the process outputs to both stdout and
   stderr.
   """
   kwargs.setdefault('stderr', subprocess2.VOID)
   kwargs.setdefault('stdout', subprocess2.PIPE)
   cmd = (GIT_EXE, '-c', 'color.ui=never') + cmd
   proc = subprocess2.Popen(cmd, **kwargs)
   return proc.stdout
 
 
+@contextlib.contextmanager
+def run_stream_with_retcode(*cmd, **kwargs):
+  """Runs a git command as context manager yielding stdout as a PIPE.
+
+  stderr is dropped to avoid races if the process outputs to both stdout and
+  stderr.
+
+  Raises subprocess2.CalledProcessError on nonzero return code.
+  """
+  kwargs.setdefault('stderr', subprocess2.VOID)
+  kwargs.setdefault('stdout', subprocess2.PIPE)
+  cmd = (GIT_EXE, '-c', 'color.ui=never') + cmd
+  try:
+    proc = subprocess2.Popen(cmd, **kwargs)
+    yield proc.stdout
+  finally:
+    retcode = proc.wait()
+    if retcode != 0:
+      raise subprocess2.CalledProcessError(retcode, cmd, os.getcwd(),
+                                           None, None)
+
+
 def run_with_stderr(*cmd, **kwargs):
   """Runs a git command.
 
   Returns (stdout, stderr) as a pair of strings.
 
   kwargs
     autostrip (bool) - Strip the output. Defaults to True.
     indata (str) - Specifies stdin data for the process.
   """
   kwargs.setdefault('stdin', subprocess2.PIPE)
@@ skipping 209 matching lines @@
         hash=branch_hash, upstream=upstream_branch, ahead=ahead, behind=behind)
 
   # Set None for upstreams which are not branches (e.g empty upstream, remotes
   # and deleted upstream branches).
   missing_upstreams = {}
   for info in info_map.values():
     if info.upstream not in info_map and info.upstream not in missing_upstreams:
       missing_upstreams[info.upstream] = None
 
   return dict(info_map.items() + missing_upstreams.items())