Catch and print OSError instead of Exception.

gclient_scm.py

 # Copyright (c) 2012 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.
 
 """Gclient-specific SCM-specific operations."""
 
 import collections
 import logging
 import os
 import posixpath
@@ skipping 743 matching lines @@
     When we go from with-cache to direct, assume that the normal url-switching
     code already flipped the remote over, and we just need to repack and break
     the dependency to the cache.
     """
 
     altfile = os.path.join(
         self.checkout_path, '.git', 'objects', 'info', 'alternates')
     if self.cache_dir:
       if not os.path.exists(altfile):
         try:
-          with open(altfile, 'wa') as f:
+          with open(altfile, 'w') as f:
             f.write(os.path.join(url, 'objects'))
           # pylint: disable=C0301
           # This dance is necessary according to emperical evidence, also at:
           # http://lists-archives.com/git/713652-retrospectively-add-alternates-to-a-repository.html
           self._Run(['repack', '-ad'], options)
           self._Run(['repack', '-adl'], options)
         except Exception:
           # If something goes wrong, try to remove the altfile so we'll go down
           # this path again next time.
           try:
             os.remove(altfile)
-          except Exception:
-            pass
+          except OSError as e:
+            print >> sys.stderr, "FAILED: os.remove('%s') -> %s" % (altfile, e)
           raise
     else:
       if os.path.exists(altfile):
         self._Run(['repack', '-a'], options)
         os.remove(altfile)
 
   def _CreateOrUpdateCache(self, url, options):
     """Make a new git mirror or update existing mirror for |url|, and return the
     mirror URI to clone from.
 
@@ skipping 718 matching lines @@
       new_command.append('--force')
       if command[0] != 'checkout' and scm.SVN.AssertVersion('1.6')[0]:
         new_command.extend(('--accept', 'theirs-conflict'))
     elif options.manually_grab_svn_rev:
       new_command.append('--force')
       if command[0] != 'checkout' and scm.SVN.AssertVersion('1.6')[0]:
         new_command.extend(('--accept', 'postpone'))
     elif command[0] != 'checkout' and scm.SVN.AssertVersion('1.6')[0]:
       new_command.extend(('--accept', 'postpone'))
     return new_command