forked from brl/citadel
166 lines
5.7 KiB
Plaintext
166 lines
5.7 KiB
Plaintext
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#!/usr/bin/env python3
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"""git-make-shallow: make the current git repository shallow
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Remove the history of the specified revisions, then optionally filter the
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available refs to those specified.
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"""
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import argparse
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import collections
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import errno
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import itertools
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import os
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import subprocess
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import sys
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version = 1.0
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def main():
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if sys.version_info < (3, 4, 0):
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sys.exit('Python 3.4 or greater is required')
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git_dir = check_output(['git', 'rev-parse', '--git-dir']).rstrip()
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shallow_file = os.path.join(git_dir, 'shallow')
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if os.path.exists(shallow_file):
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try:
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check_output(['git', 'fetch', '--unshallow'])
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except subprocess.CalledProcessError:
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try:
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os.unlink(shallow_file)
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except OSError as exc:
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if exc.errno != errno.ENOENT:
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raise
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args = process_args()
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revs = check_output(['git', 'rev-list'] + args.revisions).splitlines()
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make_shallow(shallow_file, args.revisions, args.refs)
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ref_revs = check_output(['git', 'rev-list'] + args.refs).splitlines()
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remaining_history = set(revs) & set(ref_revs)
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for rev in remaining_history:
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if check_output(['git', 'rev-parse', '{}^@'.format(rev)]):
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sys.exit('Error: %s was not made shallow' % rev)
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filter_refs(args.refs)
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if args.shrink:
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shrink_repo(git_dir)
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subprocess.check_call(['git', 'fsck', '--unreachable'])
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def process_args():
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# TODO: add argument to automatically keep local-only refs, since they
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# can't be easily restored with a git fetch.
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parser = argparse.ArgumentParser(description='Remove the history of the specified revisions, then optionally filter the available refs to those specified.')
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parser.add_argument('--ref', '-r', metavar='REF', action='append', dest='refs', help='remove all but the specified refs (cumulative)')
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parser.add_argument('--shrink', '-s', action='store_true', help='shrink the git repository by repacking and pruning')
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parser.add_argument('revisions', metavar='REVISION', nargs='+', help='a git revision/commit')
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if len(sys.argv) < 2:
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parser.print_help()
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sys.exit(2)
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args = parser.parse_args()
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if args.refs:
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args.refs = check_output(['git', 'rev-parse', '--symbolic-full-name'] + args.refs).splitlines()
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else:
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args.refs = get_all_refs(lambda r, t, tt: t == 'commit' or tt == 'commit')
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args.refs = list(filter(lambda r: not r.endswith('/HEAD'), args.refs))
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args.revisions = check_output(['git', 'rev-parse'] + ['%s^{}' % i for i in args.revisions]).splitlines()
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return args
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def check_output(cmd, input=None):
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return subprocess.check_output(cmd, universal_newlines=True, input=input)
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def make_shallow(shallow_file, revisions, refs):
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"""Remove the history of the specified revisions."""
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for rev in follow_history_intersections(revisions, refs):
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print("Processing %s" % rev)
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with open(shallow_file, 'a') as f:
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f.write(rev + '\n')
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def get_all_refs(ref_filter=None):
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"""Return all the existing refs in this repository, optionally filtering the refs."""
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ref_output = check_output(['git', 'for-each-ref', '--format=%(refname)\t%(objecttype)\t%(*objecttype)'])
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ref_split = [tuple(iter_extend(l.rsplit('\t'), 3)) for l in ref_output.splitlines()]
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if ref_filter:
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ref_split = (e for e in ref_split if ref_filter(*e))
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refs = [r[0] for r in ref_split]
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return refs
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def iter_extend(iterable, length, obj=None):
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"""Ensure that iterable is the specified length by extending with obj."""
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return itertools.islice(itertools.chain(iterable, itertools.repeat(obj)), length)
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def filter_refs(refs):
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"""Remove all but the specified refs from the git repository."""
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all_refs = get_all_refs()
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to_remove = set(all_refs) - set(refs)
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if to_remove:
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check_output(['xargs', '-0', '-n', '1', 'git', 'update-ref', '-d', '--no-deref'],
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input=''.join(l + '\0' for l in to_remove))
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def follow_history_intersections(revisions, refs):
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"""Determine all the points where the history of the specified revisions intersects the specified refs."""
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queue = collections.deque(revisions)
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seen = set()
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for rev in iter_except(queue.popleft, IndexError):
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if rev in seen:
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continue
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parents = check_output(['git', 'rev-parse', '%s^@' % rev]).splitlines()
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yield rev
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seen.add(rev)
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if not parents:
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continue
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check_refs = check_output(['git', 'merge-base', '--independent'] + sorted(refs)).splitlines()
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for parent in parents:
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for ref in check_refs:
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print("Checking %s vs %s" % (parent, ref))
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try:
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merge_base = check_output(['git', 'merge-base', parent, ref]).rstrip()
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except subprocess.CalledProcessError:
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continue
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else:
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queue.append(merge_base)
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def iter_except(func, exception, start=None):
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"""Yield a function repeatedly until it raises an exception."""
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try:
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if start is not None:
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yield start()
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while True:
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yield func()
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except exception:
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pass
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def shrink_repo(git_dir):
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"""Shrink the newly shallow repository, removing the unreachable objects."""
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subprocess.check_call(['git', 'reflog', 'expire', '--expire-unreachable=now', '--all'])
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subprocess.check_call(['git', 'repack', '-ad'])
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try:
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os.unlink(os.path.join(git_dir, 'objects', 'info', 'alternates'))
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except OSError as exc:
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if exc.errno != errno.ENOENT:
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raise
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subprocess.check_call(['git', 'prune', '--expire', 'now'])
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if __name__ == '__main__':
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main()
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