This repo contains tools for the Bugzilla bzr-git migration.
These scripts require git, bzr, the bzr fast-export plugin, perl, and C#/mono. On Ubuntu, you can install these packages:
- git
- bzr
- bzr-fastimport
- perl
- mono-mcs
This bash script exports all relevant Bazaar repos at bzr.mozilla.org to git repos at git.mozilla.org using the other tools in this repo. Logically related branches, e.g. Bugzilla versions, are created as different git branches in the same git repo. Other standalone branches are exported as just a master branch in a new repo. Note that a few git repos will not have the standard master branch, since they have no associated bzr trunk branch.
A few Bazaar branches are not migrated due to them being irrelevant or broken.
This script is intended to be used during the initial export/import.
Bugzilla has been using bzr commit properties to store info from corresponding Bugzilla bugs. In order to preserve this data when doing the initial migration from bzr to git, one needs to run
bzr fast-export --no-plain
However, since git doesn't have the concept of commit properties,
piping this data into git fast-import results in errors. We can,
however, translate the fast-export output by storing commit properties
in the git commit messages. Even better, we can check if the bug
number is already present in the commit message and only add the bug
info if it isn't.
FastImportRewriter.cs is a C# script that does just this. It is based
on one given in a blog post by David Roth that deals with this
exact problem. It only required a few modifications, so I didn't
bother translating it into another language. It runs fine under mono
on Linux: run mcs FastImportRewriter.cs to compile, and mono FastImportRewriter.exe to run. It accepts input on stdin and
produces translated output on stdout.
These are the full steps to migrate trunk (which maps to master in git terminology), starting from scratch:
cd /tmp
bzr branch https://bzr.mozilla.org/bugzilla/trunk/
cd trunk
git init
bzr fast-export --git-branch=master --no-plain | mono /path/to/FastImportRewriter.exe | git fast-import
rm -rf .bzr
git reset --hard
At this point you can create a remote repo and push to it:
git remote add origin <remote URL>
git push origin master
You can follow the same steps for other branches. Since git branches aren't tightly related to each other, unlike it other VCSes, you can start from scratch with another bzr branch and just put to a new branch in the same destination repo.
This Perl script, based on the previous bzr-to-cvs.pl script, keeps a bzr repo in sync with a git repo. It's unidirectional, from git to bzr. It's designed to be run periodically, e.g. from cron. It needs to be run once per branch like so:
./git-to-bzr.pl --from-repo=<source repo> --from-branch=<source branch> --to-repo=<dest repo> --to-branch=<dest branch>
No bzr commit properties are created, since this concept doesn't exist in git.
The -v option can be given to see some command output and other messages. Without it, only errors will be printed.
Before this is first run, you must commit a .gitrev file to each destination bzr branch that contains the full ID of the last git commit of that branch. The script uses this file to determine new commits, and it updates and commits it automatically.
You can always test this yourself:
- Create a local Bugzilla branch from upstream, e.g.
bzr branch https://bzr.mozilla.org/bugzilla/4.2/. - Create a local, empty git repo elsewhere via
git init. - Perform a migration as described in the section above.
- Edit git-to-bzr.pl to specify paths to your local bzr branch and git repo.
- Check in a .gitrev file to your local Bugzilla branch containing the ID of the last git commit.
- Make some commits to your git repo.
- Run git-to-bzr.pl with the appropriate branch name(s).
Each commit should be preserved individually.