Don't clean up after conflict in "git cl patch"

git_cl.py

 #!/usr/bin/env python
 # 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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 from distutils.version import LooseVersion
@@ skipping 2565 matching lines @@
       RunGit(['branch', '-D', options.newbranch],
           stderr=subprocess2.PIPE, error_ok=True)
     RunGit(['checkout', '-b', options.newbranch,
             Changelist().GetUpstreamBranch()])
 
   return PatchIssue(issue_arg, options.reject, options.nocommit,
                     options.directory, auth_config)
 
 
 def PatchIssue(issue_arg, reject, nocommit, directory, auth_config):
-  # There's a "reset --hard" when failing to apply the patch. In order
+  # When a patch fails to apply, it mixes with local changes. In order
   # not to destroy users' data, make sure the tree is not dirty here.

[Sam Clegg, 2015/04/20 23:32:16]

How about:

PatchIssue should never be called with a dirty tree.  Its up to the
caller to check this, but just in case we assert here since the
consequences of the caller not checking this could be dire.

[wychen, 2015/04/22 00:23:18]

Done.

   assert(not git_common.is_dirty_git_tree('apply'))
 
   if type(issue_arg) is int or issue_arg.isdigit():
     # Input is an issue id.  Figure out the URL.
     issue = int(issue_arg)
     cl = Changelist(issue=issue, auth_config=auth_config)
     patchset = cl.GetMostRecentPatchset()
     patch_data = cl.GetPatchSetDiff(issue, patchset)
   else:
     # Assume it's a URL to the patch. Default to https.
@@ skipping 30 matching lines @@
   if directory:
     cmd.extend(('--directory', directory))
   if reject:
     cmd.append('--reject')
   elif IsGitVersionAtLeast('1.7.12'):
     cmd.append('--3way')
   try:
     subprocess2.check_call(cmd, env=GetNoGitPagerEnv(),
                            stdin=patch_data, stdout=subprocess2.VOID)
   except subprocess2.CalledProcessError:
-    RunGit(['reset', '--hard'])
-    DieWithError('Failed to apply the patch')
+    print 'Failed to apply the patch'
+    return 1
 
   # If we had an issue, commit the current state and register the issue.
   if not nocommit:
     RunGit(['commit', '-m', ('patch from issue %(i)s at patchset '
                              '%(p)s (http://crrev.com/%(i)s#ps%(p)s)'
                              % {'i': issue, 'p': patchset})])
     cl = Changelist(auth_config=auth_config)
     cl.SetIssue(issue)
     cl.SetPatchset(patchset)
     print "Committed patch locally."
@@ skipping 318 matching lines @@
     DieWithError('No issue found for current branch (%s)' % branch)
   TMP_BRANCH = 'git-cl-diff'
   base_branch = cl.GetCommonAncestorWithUpstream()
 
   # Create a new branch based on the merge-base
   RunGit(['checkout', '-q', '-b', TMP_BRANCH, base_branch])
   try:
     # Patch in the latest changes from rietveld.
     rtn = PatchIssue(issue, False, False, None, auth_config)
     if rtn != 0:
+      RunGit(['reset', '--hard'])
       return rtn
 
     # Switch back to starting branch and diff against the temporary
     # branch containing the latest rietveld patch.
     subprocess2.check_call(['git', 'diff', TMP_BRANCH, branch, '--'])
   finally:
     RunGit(['checkout', '-q', branch])
     RunGit(['branch', '-D', TMP_BRANCH])
 
   return 0
@@ skipping 214 matching lines @@
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   colorama.init()
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)