Don't "hang" gclient if fast-forward is not possible.

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 logging
 import os
 import posixpath
 import re
@@ skipping 51 matching lines @@
   index_string = "diff --git "
 
   def SetCurrentFile(self, current_file):
     # Get filename by parsing "a/<filename> b/<filename>"
     self._current_file = current_file[:(len(current_file)/2)][2:]
 
   def _Replace(self, line):
     return re.sub("[a|b]/" + self._current_file, self._replacement_file, line)
 
 
-def ask_for_data(prompt):
+def ask_for_data(prompt, options):
+  if options.jobs > 1:
+    raise gclient_utils.Error("Background task requires input. Rerun "
+                              "gclient with --jobs=1 so that\n"
+                              "interaction is possible.")
   try:
     return raw_input(prompt)
   except KeyboardInterrupt:
     # Hide the exception.
     sys.exit(1)
 
 
 ### SCM abstraction layer
 
 # Factory Method for SCM wrapper creation
@@ skipping 364 matching lines @@
       # case 3 - the default case
       files = self._Capture(['diff', upstream_branch, '--name-only']).split()
       if verbose:
         print('Trying fast-forward merge to branch : %s' % upstream_branch)
       try:
         merge_args = ['merge']
         if not options.merge:
           merge_args.append('--ff-only')
         merge_args.append(upstream_branch)
         merge_output = scm.GIT.Capture(merge_args, cwd=self.checkout_path)
-      except subprocess2.CalledProcessError, e:
+      except subprocess2.CalledProcessError as e:
         if re.match('fatal: Not possible to fast-forward, aborting.', e.stderr):
           if not printed_path:
             print('\n_____ %s%s' % (self.relpath, rev_str))
             printed_path = True
           while True:
             try:
-              # TODO(maruel): That can't work with --jobs.
               action = ask_for_data(
                   'Cannot fast-forward merge, attempt to rebase? '
-                  '(y)es / (q)uit / (s)kip : ')
+                  '(y)es / (q)uit / (s)kip : ', options)
             except ValueError:
               raise gclient_utils.Error('Invalid Character')
             if re.match(r'yes|y', action, re.I):
               self._AttemptRebase(upstream_branch, files, options,
                                   printed_path=printed_path)
               printed_path = True
               break
             elif re.match(r'quit|q', action, re.I):
               raise gclient_utils.Error("Can't fast-forward, please merge or "
                                         "rebase manually.\n"
@@ skipping 270 matching lines @@
       rebase_output = scm.GIT.Capture(rebase_cmd, cwd=self.checkout_path)
     except subprocess2.CalledProcessError, e:
       if (re.match(r'cannot rebase: you have unstaged changes', e.stderr) or
           re.match(r'cannot rebase: your index contains uncommitted changes',
                    e.stderr)):
         while True:
           rebase_action = ask_for_data(
               'Cannot rebase because of unstaged changes.\n'
               '\'git reset --hard HEAD\' ?\n'
               'WARNING: destroys any uncommitted work in your current branch!'
-              ' (y)es / (q)uit / (s)how : ')
+              ' (y)es / (q)uit / (s)how : ', options)
           if re.match(r'yes|y', rebase_action, re.I):
             self._Run(['reset', '--hard', 'HEAD'], options)
             # Should this be recursive?
             rebase_output = scm.GIT.Capture(rebase_cmd, cwd=self.checkout_path)
             break
           elif re.match(r'quit|q', rebase_action, re.I):
             raise gclient_utils.Error("Please merge or rebase manually\n"
                                       "cd %s && git " % self.checkout_path
                                       + "%s" % ' '.join(rebase_cmd))
           elif re.match(r'show|s', rebase_action, re.I):
@@ skipping 507 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