I spent some time over the weekend with git yesterday, so
I finally have an opinion about it.
Distributed revision control systems are absolutely fabulous. If you haven’t
given one a serious go yet, you really should. My favorite is
darcs. This post will address git from the
perspective of a darcs user, and I might throw some comparisons to CVS or
Subversion in, too.
git is really a lot easier to use than I had anticipated. I read lots of
warnings in the documentation about how git is stupid (by definition, this is
one of its goals) and how unless your needs are a lot like Linus’ needs, it
won’t be right for you. I’ve found that to be unnecessary modesty. git is very
usable as a distributed revision control system for normal people on any size
of project. It’s not as nice as darcs, IMO, but it does have better performance
for large projects, and it doesn’t trail far behind anyway. It’s a lot nicer
to use than GNU Arch, even in its raw form.
git pretends not to be an SCM, but rather a “filesystem”. Whatever. git was
written to do what Linus needed from an SCM, and it has never had any other
purpose. Although it is conceivable that git could be used for other things, as
it is quite general and flexible, that doesn’t make it not an SCM. It certainly
is like no SCM you’ve ever seen (at the low level) but it’s still basically an
SCM.
Nevertheless, if you look too close at git you’ll be either overwhelmed by the
sheer volume of low-level filesystem-like commands, or thrilled by them.
However you don’t need most of them, and if you ignore them you can enjoy git
usability, with the added security of knowing that should you need to doctor
your repository (or have a git guru do so) all the low-level commands you need
are there. That is a bonus in my book, but mostly theoretical.
I think originally git had fewer scm-like commands and so people wrote
Porcelains, like Cogito.
Cogito is supposed to be easier to use and a more perfect SCM built on top of
git. Frankly, I can’t tell the difference between Cogito and git core, except
that git core has more commands and options. Cogito does use slightly different
terminology and command names, which only confuses the game. I think I’d rather
learn the git commands and options that I need from well-written documentation
and ignore the rest, than confuse myself with cogito. After only an hour or two
of experience, I may be really missing the boat, so you might want to check it
out anyway.
Compared to darcs, git feels very familiar. darcs’ UI is more polished, but git
has a much richer set of commands. One primary difference is that git does
branching, where in darcs a branch is basically a new copy of the repository.
Both are valid approaches, but the git approach does take less disk space (and
network bandwidth) which is important for 300-400 megabyte repositories, like
the kernel. I think I will probably continue using darcs primarily, but I will
probably try out git more in earnest when I get a chance to see if it might be
time to switch.
One thing I do not like about git is the tendency people have for providing
their driver for hardware X in the linux kernel as a git repository. Hello!
Nobody wants to download 350MB for your 10k of changes to the kernel. Nobody
wants to run your bleeding edge git repository just so they can get your
driver. That’s idiotic. git makes it easy to make patches against whatever
revision you want, so make patches against the latest stable kernel, or
whatever RC version if necessary, and call it good. Providing access to your
git repo is fine for developers, but don’t expect it of users.
In summary, I will be using git for my kernels from now on. It will be easier
to move around between versions, save me disk space, and allow me to do minor
hacks without worrying about them surviving the next kernel upgrade patch. If I
didn’t already know and love darcs, I’d start using git for my projects. If you
have wanted to investigate distributed revision control, check out darcs and
git and go with whichever your gut tells you to, I think either one will serve
your needs well. For heaven’s sake, stop using CVS in any case!