blob: 09eaffa0f8a5da76a58b5d46bc5a13ecaf844e30 [file] [log] [blame]
#!/usr/bin/env python
# Copyright 2014 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.
Tool to update all branches to have the latest changes from their upstreams.
import argparse
import collections
import logging
import sys
import textwrap
from pprint import pformat
import git_common as git
STARTING_BRANCH_KEY = 'depot-tools.rebase-update.starting-branch'
def find_return_branch():
"""Finds the branch which we should return to after rebase-update completes.
This value may persist across multiple invocations of rebase-update, if
rebase-update runs into a conflict mid-way.
return_branch = git.config(STARTING_BRANCH_KEY)
if not return_branch:
return_branch = git.current_branch()
if return_branch != 'HEAD':
git.set_config(STARTING_BRANCH_KEY, return_branch)
return return_branch
def fetch_remotes(branch_tree):
"""Fetches all remotes which are needed to update |branch_tree|."""
fetch_tags = False
remotes = set()
tag_set = git.tags()
for parent in branch_tree.itervalues():
if parent in tag_set:
fetch_tags = True
full_ref ='rev-parse', '--symbolic-full-name', parent)
if full_ref.startswith('refs/remotes'):
parts = full_ref.split('/')
remote_name = parts[2]
fetch_args = []
if fetch_tags:
# Need to fetch all because we don't know what remote the tag comes from :(
# TODO(iannucci): assert that the tags are in the remote fetch refspec
fetch_args = ['--all']
# TODO(iannucci): Should we fetch git-svn?
if not fetch_args: # pragma: no cover
print 'Nothing to fetch.'
git.run_with_stderr('fetch', *fetch_args, stdout=sys.stdout,
def remove_empty_branches(branch_tree):
tag_set = git.tags()
ensure_root_checkout = git.once(lambda:'checkout', git.root()))
deletions = set()
downstreams = collections.defaultdict(list)
for branch, parent in git.topo_iter(branch_tree, top_down=False):
if git.hash_one(branch) == git.hash_one(parent):
logging.debug('branch %s merged to %s', branch, parent)
for down in downstreams[branch]:
if down in deletions:
if parent in tag_set:
git.set_branch_config(down, 'remote', '.')
git.set_branch_config(down, 'merge', 'refs/tags/%s' % parent)
print ('Reparented %s to track %s [tag] (was tracking %s)'
% (down, parent, branch))
else:'branch', '--set-upstream-to', parent, down)
print ('Reparented %s to track %s (was tracking %s)'
% (down, parent, branch))
print'branch', '-d', branch)
def rebase_branch(branch, parent, start_hash):
logging.debug('considering %s(%s) -> %s(%s) : %s',
branch, git.hash_one(branch), parent, git.hash_one(parent),
# If parent has FROZEN commits, don't base branch on top of them. Instead,
# base branch on top of whatever commit is before them.
back_ups = 0
orig_parent = parent
while'log', '-n1', '--format=%s',
parent, '--').startswith(git.FREEZE):
back_ups += 1
parent ='rev-parse', parent+'~')
if back_ups:
logging.debug('Backed parent up by %d from %s to %s',
back_ups, orig_parent, parent)
if git.hash_one(parent) != start_hash:
# Try a plain rebase first
print 'Rebasing:', branch
if not git.rebase(parent, start_hash, branch, abort=True).success:
# TODO(iannucci): Find collapsible branches in a smarter way?
print "Failed! Attempting to squash", branch, "...",
squash_branch = branch+"_squash_attempt"'checkout', '-b', squash_branch)
# Try to rebase the branch_squash_attempt branch to see if it's empty.
squash_ret = git.rebase(parent, start_hash, squash_branch, abort=True)
empty_rebase = git.hash_one(squash_branch) == git.hash_one(parent)'checkout', branch)'branch', '-D', squash_branch)
if squash_ret.success and empty_rebase:
print 'Success!'
git.rebase(parent, start_hash, branch)
# rebase and leave in mid-rebase state.
git.rebase(parent, start_hash, branch)
print "Failed!"
print "Here's what git-rebase had to say:"
print squash_ret.message
print textwrap.dedent(
Squashing failed. You probably have a real merge conflict.
Your working copy is in mid-rebase. Either:
* completely resolve like a normal git-rebase; OR
* abort the rebase and mark this branch as dormant:
git config branch.%s.dormant true
And then run `git rebase-update` again to resume.
""" % branch)
return False
print '%s up-to-date' % branch
return True
def main(args=()):
parser = argparse.ArgumentParser()
parser.add_argument('--verbose', '-v', action='store_true')
parser.add_argument('--no_fetch', '--no-fetch', '-n',
help='Skip fetching remotes.')
opts = parser.parse_args(args)
if opts.verbose: # pragma: no cover
# TODO(iannucci): snapshot all branches somehow, so we can implement
# `git rebase-update --undo`.
# * Perhaps just copy packed-refs + refs/ + logs/ to the side?
# * commit them to a secret ref?
# * Then we could view a summary of each run as a
# `diff --stat` on that secret ref.
if git.in_rebase():
# TODO(iannucci): Be able to resume rebase with flags like --continue,
# etc.
print (
'Rebase in progress. Please complete the rebase before running '
'`git rebase-update`.'
return 1
return_branch = find_return_branch()
if git.current_branch() == 'HEAD':
if'status', '--porcelain'):
print 'Cannot rebase-update with detached head + uncommitted changes.'
return 1
git.freeze() # just in case there are any local changes.
skipped, branch_tree = git.get_branch_tree()
for branch in skipped:
print 'Skipping %s: No upstream specified' % branch
if not opts.no_fetch:
merge_base = {}
for branch, parent in branch_tree.iteritems():
merge_base[branch] = git.get_or_create_merge_base(branch, parent)
logging.debug('branch_tree: %s' % pformat(branch_tree))
logging.debug('merge_base: %s' % pformat(merge_base))
retcode = 0
# Rebase each branch starting with the root-most branches and working
# towards the leaves.
for branch, parent in git.topo_iter(branch_tree):
if git.is_dormant(branch):
print 'Skipping dormant branch', branch
ret = rebase_branch(branch, parent, merge_base[branch])
if not ret:
retcode = 1
if not retcode:
# return_branch may not be there any more.
if return_branch in git.branches():'checkout', return_branch)
root_branch = git.root()
if return_branch != 'HEAD':
print (
"%r was merged with its parent, checking out %r instead."
% (return_branch, root_branch)
)'checkout', root_branch)
git.set_config(STARTING_BRANCH_KEY, '')
return retcode
if __name__ == '__main__': # pragma: no cover