Code review comment for lp:~jml/launchpad/better-sourcecode-update

This branch adds a script that updates the branches in sourcecode, using Bazaar itself. Although rocketfuel-get already does this, the facility for doing so is untested and grouped together with a lot of other code.

By extracting the behaviour out into its own script, and indeed its owned tested functions, this patch opens up opportunities for ec2 image generation, and for getting us closer to being able to get started with Launchpad development without running rocketfuel-setup.

The tests are reasonably complete, in terms of logic. However, they begin to fall down at the point of actually doing stuff with Bazaar. This is mostly because I got stuck there, not able to figure out how to test that bit sanely.

For the utility to be useful, it really should have a nice command-line UI, be well-documented and provide good errors. It doesn't do that right now, and I'd appreciate it if you pushed me into making it do so, along with some specific notes.

One interesting thing about this branch is the way it makes a new top-level package called 'devutils'. It adds this package to the bin/test template so we can actually run the tests ("./bin/test -cvv devutils", btw). The script itself is put in utilities/ and deliberately kept as empty as possible.

The script takes about 2m to run when there's nothing to actually do. rsync takes about 12s to do the same. Although I have no way of actually measuring this, I'm confident that the script will be faster than rsync when there actually are updates. I don't really know where that extra 6s per branch is going.

There are two things I can think of to take this work further. One is to have the script be symlink-aware, so that it can be run on the sourcecode/ directory of a branch, but actually make new branches in the _real_ sourcecode directory. The second is to have rocketfuel-get use this script.

That's about all I can think of. Your opinions are greatly valued.

jml