The Changelog

Ted Ts'o had an interesting post about git recently. He has a lot of good thoughts on the subject. He comments that he wound up using git because it's so Unixy (with its small commands to do things), that he sees the git community developing innovations faster than Mercurial, and that they are working to improve the documentation and user interface problems.

The being so Unixy is a double-edged sword. On the one hand, it can make it easy to write shell scripts to extend Git. That itself can be a double-edged sword (think filename quoting and the like). But one doesn't have to use the shell. The other downside is that being Unixy makes it hard to run on platforms that aren't, such as Windows. So if one is working on Unix-only software (X, the kernel, e2fsprogs, etc.), there's no need to care about it. But if you're a person like me, who has Windows users using my software, or a large organization like Mozilla, it's maybe a showstopper. Of course, workarounds exist (cygwin, git-cvsserver), but none of them are particularly nice.

I think that both Git and Mercurial are working to address their shortcomings. I've chosen hg for now because it does what I need now. And because there are very nice tools to convert hg to git, and vice-versa. So if Ted's right, and a year from now git is easier to use, better documented, more featureful, and runs well on Windows, it won't be that hard to switch over and preserve history. Ted's the sort of person that usually is right, so maybe I should starting looking at hg2git right now

So following up on my bzr post, here are the things that Mercurial is great at right now:

1. Performance. Approximately even with git, occasionally faster. Nobody else can compete with these two right now.
2. Simplicity. It's almost as easy to get started as with darcs, and with recent patches, will be even closer in the future.
3. Lots of ways to interact. You can send hg bundles, which preserve all metadata (parents, hash, authors, etc), or you can send git-format email patches, or you can push and pull between repos. The email tools will shortly be able to automatically detect what patches to send. Your choice. git doesn't seem to support lossless emailing of bundles like this, and bzr doesn't make emailing of anything easy by default.
4. Merging. hg seems to be able to automatically resolve more merge conflicts than anything else, and when it can't automatically resolve them, has a nicely configurable system to let you use your choice of tool to manually resolve them.
5. Community. The Mercurial community is open and inviting, and open to new/different ideas. It seems similar to Darcs in that respect, and somewhat dissimilar to git.
6. Rebase does not trash history like it does (barring undocumented manual intervention) in git.

I've written before about Darcs, so I won't duplicate that here.