Fix gclient branch ref mangling and allow --force branch switches.

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."""
 
 from __future__ import print_function
 
 import errno
 import logging
@@ skipping 351 matching lines @@
     rev_str = ' at %s' % revision
     files = [] if file_list is not None else None
 
     printed_path = False
     verbose = []
     if options.verbose:
       self.Print('_____ %s%s' % (self.relpath, rev_str), timestamp=False)
       verbose = ['--verbose']
       printed_path = True
 
-    if revision.startswith('refs/'):
+    remote_ref = scm.GIT.RefToRemoteRef(revision, self.remote)
+    if remote_ref:
+      # Rewrite remote refs to their local equivalents.
+      revision = ''.join(remote_ref)
       rev_type = "branch"
-    elif revision.startswith(self.remote + '/'):
-      # Rewrite remote refs to their local equivalents.
-      revision = 'refs/remotes/' + revision
+    elif revision.startswith('refs/'):
+      # Local branch? We probably don't want to support, since DEPS should
+      # always specify branches as they are in the upstream repo.
       rev_type = "branch"
     else:
       # hash is also a tag, only make a distinction at checkout
       rev_type = "hash"
 
     mirror = self._GetMirror(url, options)
     if mirror:
       url = mirror.mirror_path
 
     if (not os.path.exists(self.checkout_path) or
         (os.path.isdir(self.checkout_path) and
          not os.path.exists(os.path.join(self.checkout_path, '.git')))):
       if mirror:
         self._UpdateMirror(mirror, options)
       try:
         self._Clone(revision, url, options)
       except subprocess2.CalledProcessError:
         self._DeleteOrMove(options.force)
         self._Clone(revision, url, options)
-      if deps_revision and deps_revision.startswith('branch-heads/'):
-        deps_branch = deps_revision.replace('branch-heads/', '')
-        self._Capture(['branch', deps_branch, deps_revision])
-        self._Checkout(options, deps_branch, quiet=True)
       if file_list is not None:
         files = self._Capture(['ls-files']).splitlines()
         file_list.extend([os.path.join(self.checkout_path, f) for f in files])
       if not verbose:
         # Make the output a little prettier. It's nice to have some whitespace
         # between projects when cloning.
         self.Print('')
       return self._Capture(['rev-parse', '--verify', 'HEAD'])
 
     if not managed:
@@ skipping 34 matching lines @@
 
     # Cases:
     # 0) HEAD is detached. Probably from our initial clone.
     #   - make sure HEAD is contained by a named ref, then update.
     # Cases 1-4. HEAD is a branch.
     # 1) current branch is not tracking a remote branch (could be git-svn)
     #   - try to rebase onto the new hash or branch
     # 2) current branch is tracking a remote branch with local committed
     #    changes, but the DEPS file switched to point to a hash
     #   - rebase those changes on top of the hash
-    # 3) current branch is tracking a remote branch w/or w/out changes,
-    #    no switch
+    # 3) current branch is tracking a remote branch w/or w/out changes, and
+    #    no DEPS switch
     #   - see if we can FF, if not, prompt the user for rebase, merge, or stop
-    # 4) current branch is tracking a remote branch, switches to a different
-    #    remote branch
-    #   - exit
+    # 4) current branch is tracking a remote branch, but DEPS switches to a
+    #    different remote branch, and
+    #   a) current branch has no local changes, and --force:
+    #      - checkout new branch
+    #   b) current branch has local changes, and --force and --reset:
+    #      - checkout new branch
+    #   c) otherwise exit
 
     # GetUpstreamBranch returns something like 'refs/remotes/origin/master' for
     # a tracking branch
     # or 'master' if not a tracking branch (it's based on a specific rev/hash)
     # or it returns None if it couldn't find an upstream
     if cur_branch is None:
       upstream_branch = None
       current_type = "detached"
       logging.debug("Detached HEAD")
     else:
@@ skipping 57 matching lines @@
           upstream_branch = revision
         self._AttemptRebase(upstream_branch, files, options,
                             printed_path=printed_path, merge=options.merge)
         printed_path = True
     elif rev_type == 'hash':
       # case 2
       self._AttemptRebase(upstream_branch, files, options,
                           newbase=revision, printed_path=printed_path,
                           merge=options.merge)
       printed_path = True
-    elif revision.replace('heads', 'remotes/' + self.remote) != upstream_branch:
+    elif remote_ref and ''.join(remote_ref) != upstream_branch:
       # case 4
-      new_base = revision.replace('heads', 'remotes/' + self.remote)
+      new_base = ''.join(remote_ref)
       if not printed_path:
         self.Print('_____ %s%s' % (self.relpath, rev_str), timestamp=False)
-      switch_error = ("Switching upstream branch from %s to %s\n"
+      switch_error = ("Could not switch upstream branch from %s to %s\n"
                      % (upstream_branch, new_base) +
-                     "Please merge or rebase manually:\n" +
+                     "Please use --force or merge or rebase manually:\n" +
                      "cd %s; git rebase %s\n" % (self.checkout_path, new_base) +
                      "OR git checkout -b <some new branch> %s" % new_base)
-      raise gclient_utils.Error(switch_error)
+      force_switch = False
+      if options.force:
+        try:
+          self._CheckClean(rev_str)
+          # case 4a
+          force_switch = True
+        except gclient_utils.Error as e:
+          if options.reset:
+            # case 4b
+            force_switch = True
+          else:
+            switch_error = '%s\n%s' % (e.message, switch_error)
+      if force_switch:
+        self.Print("Switching upstream branch from %s to %s" %
+                   (upstream_branch, new_base))
+        switch_branch = 'gclient_' + remote_ref[1]
+        self._Capture(['branch', '-f', switch_branch, new_base])
+        self._Checkout(options, switch_branch, force=True, quiet=True)
+      else:
+        # case 4c
+        raise gclient_utils.Error(switch_error)
     else:
       # case 3 - the default case
       if files is not None:
         files = self._Capture(['diff', upstream_branch, '--name-only']).split()
       if verbose:
         self.Print('Trying fast-forward merge to branch : %s' % upstream_branch)
       try:
         merge_args = ['merge']
         if options.merge:
           merge_args.append('--ff')
@@ skipping 305 matching lines @@
     except:
       traceback.print_exc(file=self.out_fh)
       raise
     finally:
       if os.listdir(tmp_dir):
         self.Print('_____ removing non-empty tmp dir %s' % tmp_dir)
       gclient_utils.rmtree(tmp_dir)
       if template_dir:
         gclient_utils.rmtree(template_dir)
     self._UpdateBranchHeads(options, fetch=True)
-    self._Checkout(options, revision.replace('refs/heads/', ''), quiet=True)
+    remote_ref = scm.GIT.RefToRemoteRef(revision, self.remote)
+    self._Checkout(options, ''.join(remote_ref or revision), quiet=True)
     if self._GetCurrentBranch() is None:
       # Squelch git's very verbose detached HEAD warning and use our own
       self.Print(
         ('Checked out %s to a detached HEAD. Before making any commits\n'
          'in this repo, you should use \'git checkout <branch>\' to switch to\n'
          'an existing branch or use \'git checkout %s -b <branch>\' to\n'
          'create a new branch for your work.') % (revision, self.remote))
 
   def _AskForData(self, prompt, options):
     if options.jobs > 1:
@@ skipping 692 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