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252 lines
7.8 KiB
Python
252 lines
7.8 KiB
Python
#!/usr/bin/env python
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# Copyright 2014 The Chromium Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""
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Tool to update all branches to have the latest changes from their upstreams.
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"""
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import argparse
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import collections
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import logging
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import sys
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import textwrap
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from pprint import pformat
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import git_common as git
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STARTING_BRANCH_KEY = 'depot-tools.rebase-update.starting-branch'
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def find_return_branch():
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"""Finds the branch which we should return to after rebase-update completes.
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This value may persist across multiple invocations of rebase-update, if
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rebase-update runs into a conflict mid-way.
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"""
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return_branch = git.config(STARTING_BRANCH_KEY)
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if not return_branch:
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return_branch = git.current_branch()
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if return_branch != 'HEAD':
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git.set_config(STARTING_BRANCH_KEY, return_branch)
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return return_branch
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def fetch_remotes(branch_tree):
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"""Fetches all remotes which are needed to update |branch_tree|."""
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fetch_tags = False
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remotes = set()
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tag_set = git.tags()
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for parent in branch_tree.itervalues():
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if parent in tag_set:
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fetch_tags = True
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else:
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full_ref = git.run('rev-parse', '--symbolic-full-name', parent)
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if full_ref.startswith('refs/remotes'):
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parts = full_ref.split('/')
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remote_name = parts[2]
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remotes.add(remote_name)
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fetch_args = []
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if fetch_tags:
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# Need to fetch all because we don't know what remote the tag comes from :(
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# TODO(iannucci): assert that the tags are in the remote fetch refspec
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fetch_args = ['--all']
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else:
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fetch_args.append('--multiple')
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fetch_args.extend(remotes)
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# TODO(iannucci): Should we fetch git-svn?
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if not fetch_args: # pragma: no cover
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print 'Nothing to fetch.'
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else:
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git.run_with_stderr('fetch', *fetch_args, stdout=sys.stdout,
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stderr=sys.stderr)
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def remove_empty_branches(branch_tree):
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tag_set = git.tags()
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ensure_root_checkout = git.once(lambda: git.run('checkout', git.root()))
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deletions = set()
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downstreams = collections.defaultdict(list)
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for branch, parent in git.topo_iter(branch_tree, top_down=False):
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downstreams[parent].append(branch)
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if git.hash_one(branch) == git.hash_one(parent):
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ensure_root_checkout()
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logging.debug('branch %s merged to %s', branch, parent)
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for down in downstreams[branch]:
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if down in deletions:
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continue
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if parent in tag_set:
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git.set_branch_config(down, 'remote', '.')
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git.set_branch_config(down, 'merge', 'refs/tags/%s' % parent)
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print ('Reparented %s to track %s [tag] (was tracking %s)'
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% (down, parent, branch))
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else:
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git.run('branch', '--set-upstream-to', parent, down)
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print ('Reparented %s to track %s (was tracking %s)'
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% (down, parent, branch))
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deletions.add(branch)
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print git.run('branch', '-d', branch)
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def rebase_branch(branch, parent, start_hash):
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logging.debug('considering %s(%s) -> %s(%s) : %s',
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branch, git.hash_one(branch), parent, git.hash_one(parent),
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start_hash)
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# If parent has FROZEN commits, don't base branch on top of them. Instead,
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# base branch on top of whatever commit is before them.
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back_ups = 0
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orig_parent = parent
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while git.run('log', '-n1', '--format=%s',
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parent, '--').startswith(git.FREEZE):
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back_ups += 1
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parent = git.run('rev-parse', parent+'~')
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if back_ups:
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logging.debug('Backed parent up by %d from %s to %s',
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back_ups, orig_parent, parent)
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if git.hash_one(parent) != start_hash:
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# Try a plain rebase first
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print 'Rebasing:', branch
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if not git.rebase(parent, start_hash, branch, abort=True).success:
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# TODO(iannucci): Find collapsible branches in a smarter way?
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print "Failed! Attempting to squash", branch, "...",
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squash_branch = branch+"_squash_attempt"
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git.run('checkout', '-b', squash_branch)
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git.squash_current_branch(merge_base=start_hash)
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# Try to rebase the branch_squash_attempt branch to see if it's empty.
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squash_ret = git.rebase(parent, start_hash, squash_branch, abort=True)
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empty_rebase = git.hash_one(squash_branch) == git.hash_one(parent)
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git.run('checkout', branch)
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git.run('branch', '-D', squash_branch)
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if squash_ret.success and empty_rebase:
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print 'Success!'
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git.squash_current_branch(merge_base=start_hash)
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git.rebase(parent, start_hash, branch)
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else:
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# rebase and leave in mid-rebase state.
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git.rebase(parent, start_hash, branch)
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print "Failed!"
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print
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print "Here's what git-rebase had to say:"
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print squash_ret.message
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print
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print textwrap.dedent(
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"""
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Squashing failed. You probably have a real merge conflict.
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Your working copy is in mid-rebase. Either:
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* completely resolve like a normal git-rebase; OR
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* abort the rebase and mark this branch as dormant:
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git config branch.%s.dormant true
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And then run `git rebase-update` again to resume.
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""" % branch)
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return False
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else:
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print '%s up-to-date' % branch
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git.remove_merge_base(branch)
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git.get_or_create_merge_base(branch)
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return True
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def main(args=()):
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parser = argparse.ArgumentParser()
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parser.add_argument('--verbose', '-v', action='store_true')
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parser.add_argument('--no_fetch', '-n', action='store_true',
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help='Skip fetching remotes.')
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opts = parser.parse_args(args)
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if opts.verbose: # pragma: no cover
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logging.getLogger().setLevel(logging.DEBUG)
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# TODO(iannucci): snapshot all branches somehow, so we can implement
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# `git rebase-update --undo`.
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# * Perhaps just copy packed-refs + refs/ + logs/ to the side?
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# * commit them to a secret ref?
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# * Then we could view a summary of each run as a
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# `diff --stat` on that secret ref.
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if git.in_rebase():
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# TODO(iannucci): Be able to resume rebase with flags like --continue,
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# etc.
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print (
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'Rebase in progress. Please complete the rebase before running '
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'`git rebase-update`.'
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)
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return 1
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return_branch = find_return_branch()
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if git.current_branch() == 'HEAD':
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if git.run('status', '--porcelain'):
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print 'Cannot rebase-update with detached head + uncommitted changes.'
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return 1
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else:
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git.freeze() # just in case there are any local changes.
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skipped, branch_tree = git.get_branch_tree()
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for branch in skipped:
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print 'Skipping %s: No upstream specified' % branch
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if not opts.no_fetch:
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fetch_remotes(branch_tree)
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merge_base = {}
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for branch, parent in branch_tree.iteritems():
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merge_base[branch] = git.get_or_create_merge_base(branch, parent)
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logging.debug('branch_tree: %s' % pformat(branch_tree))
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logging.debug('merge_base: %s' % pformat(merge_base))
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retcode = 0
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# Rebase each branch starting with the root-most branches and working
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# towards the leaves.
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for branch, parent in git.topo_iter(branch_tree):
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if git.is_dormant(branch):
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print 'Skipping dormant branch', branch
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else:
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ret = rebase_branch(branch, parent, merge_base[branch])
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if not ret:
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retcode = 1
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break
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if not retcode:
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remove_empty_branches(branch_tree)
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# return_branch may not be there any more.
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if return_branch in git.branches():
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git.run('checkout', return_branch)
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git.thaw()
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else:
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root_branch = git.root()
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if return_branch != 'HEAD':
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print (
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"%r was merged with its parent, checking out %r instead."
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% (return_branch, root_branch)
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)
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git.run('checkout', root_branch)
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git.set_config(STARTING_BRANCH_KEY, '')
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return retcode
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if __name__ == '__main__': # pragma: no cover
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sys.exit(main(sys.argv[1:]))
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