blob: 4545ec96c14be4c00b88b62b14e027c4e6abc287 [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
import os
from fnmatch import fnmatch
from pprint import pformat
import git_common as git
STARTING_BRANCH_KEY = 'depot-tools.rebase-update.starting-branch'
STARTING_WORKDIR_KEY = 'depot-tools.rebase-update.starting-workdir'
def find_return_branch_workdir():
"""Finds the branch and working directory which we should return to after
rebase-update completes.
These values may persist across multiple invocations of rebase-update, if
rebase-update runs into a conflict mid-way.
return_branch = git.get_config(STARTING_BRANCH_KEY)
workdir = git.get_config(STARTING_WORKDIR_KEY)
if not return_branch:
workdir = os.getcwd()
git.set_config(STARTING_WORKDIR_KEY, workdir)
return_branch = git.current_branch()
if return_branch != 'HEAD':
git.set_config(STARTING_BRANCH_KEY, return_branch)
return return_branch, workdir
def fetch_remotes(branch_tree):
"""Fetches all remotes which are needed to update |branch_tree|."""
fetch_tags = False
remotes = set()
tag_set = git.tags()
fetchspec_map = {}
all_fetchspec_configs = git.get_config_regexp(r'^remote\..*\.fetch')
for fetchspec_config in all_fetchspec_configs:
key, _, fetchspec = fetchspec_config.partition(' ')
dest_spec = fetchspec.partition(':')[2]
remote_name = key.split('.')[1]
fetchspec_map[dest_spec] = remote_name
for parent in branch_tree.itervalues():
if parent in tag_set:
fetch_tags = True
full_ref ='rev-parse', '--symbolic-full-name', parent)
for dest_spec, remote_name in fetchspec_map.iteritems():
if fnmatch(full_ref, dest_spec):
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 = {}
reparents = {}
downstreams = collections.defaultdict(list)
for branch, parent in git.topo_iter(branch_tree, top_down=False):
# If branch and parent have the same tree, then branch has to be marked
# for deletion and its children and grand-children reparented to parent.
if git.hash_one(branch+":") == git.hash_one(parent+":"):
logging.debug('branch %s merged to %s', branch, parent)
# Mark branch for deletion while remembering the ordering, then add all
# its children as grand-children of its parent and record reparenting
# information if necessary.
deletions[branch] = len(deletions)
for down in downstreams[branch]:
if down in deletions:
# Record the new and old parent for down, or update such a record
# if it already exists. Keep track of the ordering so that reparenting
# happen in topological order.
if down not in reparents:
reparents[down] = (len(reparents), parent, branch)
order, _, old_parent = reparents[down]
reparents[down] = (order, parent, old_parent)
# Apply all reparenting recorded, in order.
for branch, value in sorted(reparents.iteritems(), key=lambda x:x[1][0]):
_, parent, old_parent = value
if parent in tag_set:
git.set_branch_config(branch, 'remote', '.')
git.set_branch_config(branch, 'merge', 'refs/tags/%s' % parent)
print ('Reparented %s to track %s [tag] (was tracking %s)'
% (branch, parent, old_parent))
else:'branch', '--set-upstream-to', parent, branch)
print ('Reparented %s to track %s (was tracking %s)'
% (branch, parent, old_parent))
# Apply all deletions recorded, in order.
for branch, _ in sorted(deletions.iteritems(), key=lambda x: x[1]):
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
rebase_ret = git.rebase(parent, start_hash, branch, abort=True)
if not rebase_ret.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)
print "Failed!"
# rebase and leave in mid-rebase state.
# This second rebase attempt should always fail in the same
# way that the first one does. If it magically succeeds then
# something very strange has happened.
second_rebase_ret = git.rebase(parent, start_hash, branch)
if second_rebase_ret.success: # pragma: no cover
print "Second rebase succeeded unexpectedly!"
print "Please see:"
print "First rebased failed with:"
print rebase_ret.stderr
print "Here's what git-rebase (squashed) had to say:"
print squash_ret.stdout
print squash_ret.stderr
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=None):
parser = argparse.ArgumentParser()
parser.add_argument('--verbose', '-v', action='store_true')
parser.add_argument('--keep-going', '-k', action='store_true',
help='Keep processing past failed rebases.')
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, return_workdir = find_return_branch_workdir()
os.chdir('rev-parse', '--show-toplevel'))
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
unrebased_branches = []
# 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 opts.keep_going:
print '--keep-going set, continuing with next branch.'
if git.in_rebase():
git.run_with_retcode('rebase', '--abort')
if git.in_rebase(): # pragma: no cover
print 'Failed to abort rebase. Something is really wrong.'
if unrebased_branches:
print 'The following branches could not be cleanly rebased:'
for branch in unrebased_branches:
print ' %s' % branch
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)
# return_workdir may also not be there any more.
if return_workdir:
except OSError as e:
print (
"Unable to return to original workdir %r: %s"
% (return_workdir, e)
git.set_config(STARTING_BRANCH_KEY, '')
git.set_config(STARTING_WORKDIR_KEY, '')
return retcode
if __name__ == '__main__': # pragma: no cover
except KeyboardInterrupt: