Add hg-to-git conversion utility.

hg-to-git.py  is able to convert a Mercurial repository into a git one,
and preserves the branches in the process (unlike tailor)

hg-to-git.py can probably be greatly improved (it's a rather crude
combination of shell and python) but it does already work quite well for
me. Features:
	- supports incremental conversion
	  (for keeping a git repo in sync with a hg one)
	- supports hg branches
	- converts hg tags

Signed-off-by: Stelian Pop <stelian@popies.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Stelian Pop 2007-01-12 22:57:03 +01:00 committed by Junio C Hamano
parent 3fb624521e
commit 98d47d4ccf
3 changed files with 262 additions and 0 deletions

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@ -86,6 +86,14 @@ Foreign SCM interface
series in git back and forth.
- *hg-to-git* (contrib/)
hg-to-git converts a Mercurial repository into a git one, and
preserves the full branch history in the process. hg-to-git can
also be used in an incremental way to keep the git repository
in sync with the master Mercurial repository.
Others
------

233
contrib/hg-to-git/hg-to-git.py Executable file
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@ -0,0 +1,233 @@
#! /usr/bin/python
""" hg-to-svn.py - A Mercurial to GIT converter
Copyright (C)2007 Stelian Pop <stelian@popies.net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
"""
import os, os.path, sys
import tempfile, popen2, pickle, getopt
import re
# Maps hg version -> git version
hgvers = {}
# List of children for each hg revision
hgchildren = {}
# Current branch for each hg revision
hgbranch = {}
#------------------------------------------------------------------------------
def usage():
print """\
%s: [OPTIONS] <hgprj>
options:
-s, --gitstate=FILE: name of the state to be saved/read
for incrementals
required:
hgprj: name of the HG project to import (directory)
""" % sys.argv[0]
#------------------------------------------------------------------------------
def getgitenv(user, date):
env = ''
elems = re.compile('(.*?)\s+<(.*)>').match(user)
if elems:
env += 'export GIT_AUTHOR_NAME="%s" ;' % elems.group(1)
env += 'export GIT_COMMITER_NAME="%s" ;' % elems.group(1)
env += 'export GIT_AUTHOR_EMAIL="%s" ;' % elems.group(2)
env += 'export GIT_COMMITER_EMAIL="%s" ;' % elems.group(2)
else:
env += 'export GIT_AUTHOR_NAME="%s" ;' % user
env += 'export GIT_COMMITER_NAME="%s" ;' % user
env += 'export GIT_AUTHOR_EMAIL= ;'
env += 'export GIT_COMMITER_EMAIL= ;'
env += 'export GIT_AUTHOR_DATE="%s" ;' % date
env += 'export GIT_COMMITTER_DATE="%s" ;' % date
return env
#------------------------------------------------------------------------------
state = ''
try:
opts, args = getopt.getopt(sys.argv[1:], 's:t:', ['gitstate=', 'tempdir='])
for o, a in opts:
if o in ('-s', '--gitstate'):
state = a
state = os.path.abspath(state)
if len(args) != 1:
raise('params')
except:
usage()
sys.exit(1)
hgprj = args[0]
os.chdir(hgprj)
if state:
if os.path.exists(state):
print 'State does exist, reading'
f = open(state, 'r')
hgvers = pickle.load(f)
else:
print 'State does not exist, first run'
tip = os.popen('hg tip | head -1 | cut -f 2 -d :').read().strip()
print 'tip is', tip
# Calculate the branches
print 'analysing the branches...'
hgchildren["0"] = ()
hgbranch["0"] = "master"
for cset in range(1, int(tip) + 1):
hgchildren[str(cset)] = ()
prnts = os.popen('hg log -r %d | grep ^parent: | cut -f 2 -d :' % cset).readlines()
if len(prnts) > 0:
parent = prnts[0].strip()
else:
parent = str(cset - 1)
hgchildren[parent] += ( str(cset), )
if len(prnts) > 1:
mparent = prnts[1].strip()
hgchildren[mparent] += ( str(cset), )
else:
mparent = None
if mparent:
# For merge changesets, take either one, preferably the 'master' branch
if hgbranch[mparent] == 'master':
hgbranch[str(cset)] = 'master'
else:
hgbranch[str(cset)] = hgbranch[parent]
else:
# Normal changesets
# For first children, take the parent branch, for the others create a new branch
if hgchildren[parent][0] == str(cset):
hgbranch[str(cset)] = hgbranch[parent]
else:
hgbranch[str(cset)] = "branch-" + str(cset)
if not hgvers.has_key("0"):
print 'creating repository'
os.system('git-init-db')
# loop through every hg changeset
for cset in range(int(tip) + 1):
# incremental, already seen
if hgvers.has_key(str(cset)):
continue
# get info
prnts = os.popen('hg log -r %d | grep ^parent: | cut -f 2 -d :' % cset).readlines()
if len(prnts) > 0:
parent = prnts[0].strip()
else:
parent = str(cset - 1)
if len(prnts) > 1:
mparent = prnts[1].strip()
else:
mparent = None
(fdcomment, filecomment) = tempfile.mkstemp()
csetcomment = os.popen('hg log -r %d -v | grep -v ^changeset: | grep -v ^parent: | grep -v ^user: | grep -v ^date | grep -v ^files: | grep -v ^description: | grep -v ^tag:' % cset).read().strip()
os.write(fdcomment, csetcomment)
os.close(fdcomment)
date = os.popen('hg log -r %d | grep ^date: | cut -f 2- -d :' % cset).read().strip()
tag = os.popen('hg log -r %d | grep ^tag: | cut -f 2- -d :' % cset).read().strip()
user = os.popen('hg log -r %d | grep ^user: | cut -f 2- -d :' % cset).read().strip()
print '-----------------------------------------'
print 'cset:', cset
print 'branch:', hgbranch[str(cset)]
print 'user:', user
print 'date:', date
print 'comment:', csetcomment
print 'parent:', parent
if mparent:
print 'mparent:', mparent
if tag:
print 'tag:', tag
print '-----------------------------------------'
# checkout the parent if necessary
if cset != 0:
if hgbranch[str(cset)] == "branch-" + str(cset):
print 'creating new branch', hgbranch[str(cset)]
os.system('git-checkout -b %s %s' % (hgbranch[str(cset)], hgvers[parent]))
else:
print 'checking out branch', hgbranch[str(cset)]
os.system('git-checkout %s' % hgbranch[str(cset)])
# merge
if mparent:
if hgbranch[parent] == hgbranch[str(cset)]:
otherbranch = hgbranch[mparent]
else:
otherbranch = hgbranch[parent]
print 'merging', otherbranch, 'into', hgbranch[str(cset)]
os.system(getgitenv(user, date) + 'git-merge --no-commit -s ours "" %s %s' % (hgbranch[str(cset)], otherbranch))
# remove everything except .git and .hg directories
os.system('find . \( -path "./.hg" -o -path "./.git" \) -prune -o ! -name "." -print | xargs rm -rf')
# repopulate with checkouted files
os.system('hg update -C %d' % cset)
# add new files
os.system('git-ls-files -x .hg --others | git-update-index --add --stdin')
# delete removed files
os.system('git-ls-files -x .hg --deleted | git-update-index --remove --stdin')
# commit
os.system(getgitenv(user, date) + 'git-commit -a -F %s' % filecomment)
os.unlink(filecomment)
# tag
if tag and tag != 'tip':
os.system(getgitenv(user, date) + 'git-tag %s' % tag)
# delete branch if not used anymore...
if mparent and len(hgchildren[str(cset)]):
print "Deleting unused branch:", otherbranch
os.system('git-branch -d %s' % otherbranch)
# retrieve and record the version
vvv = os.popen('git-show | head -1').read()
vvv = vvv[vvv.index(' ') + 1 : ].strip()
print 'record', cset, '->', vvv
hgvers[str(cset)] = vvv
os.system('git-repack -a -d')
# write the state for incrementals
if state:
print 'Writing state'
f = open(state, 'w')
pickle.dump(hgvers, f)
# vim: et ts=8 sw=4 sts=4

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@ -0,0 +1,21 @@
hg-to-git.py is able to convert a Mercurial repository into a git one,
and preserves the branches in the process (unlike tailor)
hg-to-git.py can probably be greatly improved (it's a rather crude
combination of shell and python) but it does already work quite well for
me. Features:
- supports incremental conversion
(for keeping a git repo in sync with a hg one)
- supports hg branches
- converts hg tags
Note that the git repository will be created 'in place' (at the same
location as the source hg repo). You will have to manually remove the
'.hg' directory after the conversion.
Also note that the incremental conversion uses 'simple' hg changesets
identifiers (ordinals, as opposed to SHA-1 ids), and since these ids
are not stable across different repositories the hg-to-git.py state file
is forever tied to one hg repository.
Stelian Pop <stelian@popies.net>