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This January, Ksplice swelled from 8 people to 20 people. You can imagine what that did to the office—it’s a good thing that Tim and Jeff have been practicing the art of rearranging a space to fit more people than ever thought possible since their days in the SIPB office. Fortunately, because we have at our disposal a computer-systems training and recruitment machine of awesome effectiveness, our interns defied Fred Brooks and produced a great deal of useful code.

The problem: how to keep track of all that new code and get it all reviewed smoothly? Our ad hoc practices relying on one-on-one exchanges clearly were not going to scale. The solution: on the first day the new interns showed up, I took a couple of hours and threw together a script to request code reviews. The key design considerations were

• Public visibility. The script sends mail, and CCs a list going to the whole team.
• Non-diffusion of responsibility. The user must identify someone to be the reviewer, and the request is addressed to them.
• Git friendliness. Being a kernel shop, we use Git for everything, so the script assumes a basic Git workflow: you make some commits, and then you request a whole series of commits to be reviewed at once.

We looked at some existing code review tools like Gerrit and Rietveld, but we weren’t happy with any of them because the ones we found don’t work on branches—they work on individual commits—and we have drunk too deeply of Git to be satisfied working that way.

On the other hand, being the product of a few hours’ work, there’s several things that could be made better. The interaction with the user could be better to prevent mis-sends. The script could do better at detecting what the repository in question is called, it could take advantage of commit messages for better subject lines, and it could try to give the reviewer a command line that will show the commits in question. (Until then: it’s usually git log -p --reverse origin/master..origin/branchname.) Someday we may also want a system that tracks what commits have been reviewed by whom and blocks commits from going in without review; that will be a bigger project.

Apparently we did something right with this script, because I heard a couple of people say they’d like to use it outside of Ksplice. So the other day we decided we were happy to release it as free software. As of last night you can get it from Github—enjoy.

Let me know if you use it, and patches welcome, of course.