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Bzr2Git -- make a git repositpry out of a bazaar one

I have used bazaar on my Thecus for my private projects. At that time, git was not available on Windows platforms.

However, during the development of solarpowerlog,  I learned that is not longer true, and after some time of usage I decided to finally switch everything to git. (bzr also showed some "hangs" on my thecus when commiting which were really annoying....

Whatever, what i missed was a small script that will do the transfer of the repositories while keeping the history.

The script does:

• copy all revisions from the bzr repository to git
• keeps author and commit date
• keeps the original commit message
• extracts all set tags and set these to on the new git repository

It does NOT

• handle branches and their merges.

Here is it: (download here: bzr2git)

	#!/bin/bash
	# bzr2git
	# (c) Tobias Frost 2009. Released under the GPL3. 
	# http://blog.coldtobi.de
	# This script takes a bazaar (bzr) repository and makes a git repository out of
	# it. The current dir should be the bzw one, the git one is created in 
	# new_git_repo.
	#
	# To commit to a different git branch, just remove the exit 1 below and before
	# invoking the script, create the branch manually in git and change to it. 
	# (note: this is untested, but should work)
	# NOTE: !!!ALWAYS USE BACKUPS!!! THIS SCRIPT MIGHT HAVE AN ERROR
	# WHICH TRIGGERS DOOMSDAY
	if [[ -e new_git_repo ]] 
	then
	echo "new_git_repo exits. Please remove it or edit this script"
	echo "alternativly, comment out the exit 1 below and go on on your own risk"
	echo "(you can then add branches to git...)"
	exit 1
	else
	# generate a git repository staging directory
	# make a empty git repository	
	mkdir new_git_repo || exit 1
	(cd new_git_repo && git init) || exit 1
	fi
	if [[ -e rev_to_merge ]] 
	then
	echo "rev_to_merge exits. Please remove it or edit this script"
	exit 1
	fi
	# ok, so lets start extracting the revs from bzr.
	for (( j=1; j<=99999 ; j++ )) 
	do	
	# Here you can pimp the revision to be checked out in order to manually merge 
	# some branch...
	# e.g i="32.1.$j" to get the branch 32.1.x 
	i=$j
	# check for log and determine if rev exists....
	bzr log --revision $i 2>/dev/null | tail -n +7 | cut -c3- > /tmp/revlog  || exit 1
	echo >>/tmp/revlog
	echo "original bzr status:" >>/tmp/revlog
	bzr log -r $i | tail -n +2 | head -n 4 >>/tmp/revlog
	#extract author and date
	AUTHOR=$(bzr log -r $i | grep ^committer: | cut -c12-)
	export GIT_COMMITTER_DATE=""
	export GIT_COMMITTER_DATE=$(bzr log -r $i | grep ^timestamp: | cut -c12-) 
	export GIT_AUTHOR_DATE=$GIT_COMMITTER_DATE
	echo $GIT_COMMITTER_DATE
	[[ "x$AUTHOR" == "x" ]] && AUTHOR="unkown"
	echo "Extracting rev $i"
	# see if there is a tag associated with this revision
	# sed: expr1 -> remove revision number
	#      expr2 -> remove trailing blanks
	#	   expr3 -> replace blanks with underscores 
	TAGS=$(bzr tags -r $i | sed -e "s/\(.*\).$i/\1/g" -e 's/[ \t]*$//' -e "s/\(.*\)/\'\1\'/g" -e "s/[[:blank:]]/_/g")
	if [[ "x$TAGS" != "x" ]] 
	then
	echo "TAGS detected."
	echo TAGS $TAGS || hexdump -C 
	fi
	bzr branch --revision $i . rev_to_merge || exit 1
	# make sure that we update the gitignore as well.
	rm -rf new_git_repo/* # remove old files or mv will complain
	mv -f rev_to_merge/.bzrignore new_git_repo/.gitignore
	mv -f rev_to_merge/* new_git_repo/ || exit 1
	# do the commit
	( cd new_git_repo && git add -A ) || exit 1
	( cd new_git_repo && git commit --author "$AUTHOR" -F /tmp/revlog ) || exit 1
	if [[ "x$TAGS" != "x" ]] 
	then
	for t in $TAGS
	do
	echo "CREATING TAG $t"
	( cd new_git_repo && git tag -a $t -m "Autoimported tag $t from bzr repository" ) || exit 1
	done
	fi
	# remove the staging dir 
	rm -rf rev_to_merge || exit 1
	done