Git, one month on

I've been using Git for about a month now. Overall, everyone has been right about it -- it's got some heinous usability problems, but man is it kick ass to have distributed version control.

For instance, I've taken a few trips since I switch to Git, and I've committed on an airplane at least twice now. This seems like a small thing, in that I could always wait to commit, but I'm often surprisingly productive in planes, and there are plenty of things you can't actually recover from in SVN without the full repository (e.g., moving directories around).

The cool things about Git don't all require its distributed aspect -- for instance, its branching is far superior ot SVN's (if you could say SVN even has branching). I found myself three commits into some work last week that really should have been a separate branch. With Git, this was really easy to do -- I branched from the current state, then rewound the current branch to remove the commits I didn't want in it.

I was in a branch named indirection, and I decided it made sense to make a new branch named configurations.

Using the git reset man page, this is what I did:

$ git branch configurations
$ git reset --hard HEAD~3
$ git checkout configurations

This left me in the new branch I wanted and left the indirections branch in the state it was at before I made the big changes.

It's clearly not all peaches and cream, though. As I mentioned, there are definite usability issues. It's not so much that you can't figure it but that it's just seldom what you expect. It doesn't help that the majority of the examples are from Linus's life, and his life is far more complicated than most, in terms of managing repositories.

The mechanism for pulling, fetching, and pushing branches is especially counterintuitive.

Overall, though, I'm very happy with it.

Sun, 23 Sep 2007 | Tags: tools, git, scm, dscm, svn, cvs

Linus on Git responding to KDE

Linus Torvalds posted a lengthy response to someone from the KDE community about using Git with KDE, and it's definitely worth a read:

Practically speaking, you'd generally have one or a few central repositories, yes. But no, it really doesn't have to be a single one. And I'm not just talking about mirroring (which is really easy with a distributed setup), I'm literally talking about things like some people wanting to use the "stable" tree, and not my tree at all, or the vendor trees.

And they are obviously connected, but it doesn't have to be a totally central notion at all.

Think of the git trees as people: some people are more "central" than others, but in the end, the kernel is actually fairly unusual (at least for a big project) in having just one person that is so much in the "center" that everybody knows about him.

Mon, 27 Aug 2007 | Tags: tools, git, kde, scm, dscm, svn, cvs

Giving Git a run-out

Something apparently snapped while I was at OSCON, and I apparently collapsed my distributed source control management quandary down to Git. I think in the end it doesn't matter all that much, since they're so similar in basic functionality, and I think I mostly got tired of sitting on the fence looking over but not being willing to commit to a specific dSCM.

Once I decided I'd go ahead with Git, my main priority was to get to the point where I could do my development on Puppet in it, which is especially important since it's the only real way for me to figure out if it will work for me, not that I really know what "work for me" means.

There are two crucial steps to testing an SCM for me: Getting Puppet's code into it, with as much history as possible, and making it available for others to have access to.

Getting the code was moderately easy, but made harder by the fact that when I first made my Subversion repository, when SVN was just starting to get popular, so I started without the typical branches/tags/trunk directory set. Here's the command I used in the end:

git svnimport -A ~/puppet-users -i -v http://reductivelabs.com/svn/puppet/ > /tmp/git.out

I tried git-svn, but it never got past revision 567 or so (which is when I switch to the popular directory structure). In addition, I was never able to actually get a working copy of the repository up to that point.

The puppet-users file contains a mapping from svn-style user names to email addresses:

luke = Luke Kanies <luke@domain.com>
lutter = David Lutterkort <dlutter@domain.com>
mpalmer = Matthew Palmer <mpalmer@domain.org>

I redirect output to a file, because it produces a bunch of output (I've got about 2800 revisions) and I don't actually care about any of it, and in addition, because I use iTerm, it takes a whole freaking cpu to scroll a terminal.

This basically worked, except that it started at revision 600 (arbitrarily close enough to the time when I changed the directory structure in the repository).

To make the repository shareable, I first just exported it via http, which was pretty easy, but then I was told I need to use git-server for performance reasons. I built a Puppet module to set it all up, and although the server doesn't work as well as I like (I really like SVN's auth file, which allows me to control who has access to the 32 repositories I maintain).

I'm getting some gritching from the Australians, and it's not like it's perfect, but at least I know I want something like that.

At the least, this has been a great experiment, and I figure we'll spend a week or so messing around with it. I'm not sure I can afford the time to experiment with all of the competitors; Matt's really pushing on darcs, but... I dunno, it seems niche, and at this point, I'm niche enough for all of us.

Tue, 07 Aug 2007 | Tags: tools, git, scm, svn, oscon, oscon07