In my previous post, I mentioned using Tailor to import jhbuild into a Bazaar-NG branch. In case anyone else is interested in doing the same, here are the steps I used:
1. Install the tools
First create a working directory to perform the import, and set up tailor. I currently use the nightly snapshots of bzr, which did not work with Tailor, so I also grabbed bzr-0.7:
$ wget http://darcs.arstecnica.it/tailor-0.9.20.tar.gz $ wget http://www.bazaar-ng.org/pkg/bzr-0.7.tar.gz $ tar xzf tailor-0.9.20.tar.gz $ tar xzf bzr-0.7.tar.gz $ ln -s ../bzr-0.7/bzrlib tailor-0.9.20/bzrlib
2. Prepare a local CVS Repository to import from
The import will run a lot faster with a local CVS repository. If you have a shell account on window.gnome.org, this is trivial to set up:
$ mkdir cvsroot $ cvs -d `pwd`/cvsroot init $ rsync -azP window.gnome.org:/cvs/gnome/jhbuild/ cvsroot/jhbuild/
3. Check for history inconsistency
As I discovered, Tailor will bomb if time goes backwards at some point in your CVS history, and will probably bomb out part way through. The quick fix for this is to directly edit the RCS ,v files to correct the dates. Since you are working with a copy of the repository, there isn’t any danger of screwing things up.
I wrote a small program to check an RCS file for such discontinuities:
When editing the dates in the RCS files, make sure that you change the dates in the different files in a consistent way. You want to make sure that revisions in different files that are part of the same changeset still have the same date after the edits.
4. Create a Tailor config file
Here is the Tailor config file I used to import jhbuild:
#! """ [DEFAULT] verbose = True projects = jhbuild encoding = utf-8 [jhbuild] target = bzr:target start-revision = INITIAL root-directory = basedir/jhbuild.cvs state-file = tailor.state source = cvs:source subdir = . before-commit = remap_author patch-name-format = [bzr:target] encoding = utf-8 [cvs:source] module = jhbuild repository = basedir/cvsroot encoding = utf-8 """ def remap_author(context, changeset): if '@' not in changeset.author: changeset.author = '%s <%firstname.lastname@example.org>' % (changeset.author, changeset.author) return True
The remap_author function at the bottom maps the CVS user names to something closer to what bzr normally uses.
5. Perform the conversion
Now it is possible to run the conversion:
$ python tailor-0.9.20/tailor -vv --configfile jhbuild.tailor
When the conversion is complete, you should be left with a bzr branch containing the history of the HEAD branch from CVS. Now is a good time to check that the converted bzr looks sane.
6. Use the new branch
Rather than using the converted branch directly, it is a good idea to branch off it and do the development there:
$ bzr branch jhbuild.cvs jhbuild.dev
The advantage of doing this is that you have the option of rsyncing in new changes to the CVS repository and running tailor again to incrementally import them. You can then merge those changes to your development branch.
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I have some vague memories that tailor wasn’t able to deal with CVS branches. Has that been fixed?
From what I can tell, it has no automatic support for branches. If you wanted to convert a branch as well as the mainline, it would be necessary to do something like:
1. convert mainline
2. figure out where the branchpoint is.
3. take a copy of the converted mainline, and uncommit up to the branch point.
4. create a new tailor config to convert the branch, telling it to start at the first revision on that branch.
Pretty ugly, but should work. As I said in my previous post: I was only interested in converting the mainline, so that’s all I’ve described.
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