Code Review is a central part of every programmer’s process: generate an idea, write the idea as code (including tests!), submit for review, incorporate review notes, merge to mainline. It’s also the only time in this process that other people are required. You can come up with your own idea and code it and write tests and merge back into mainline without any input from anyone else! But code review is essentially the idea that your code has fewer bugs and greater logical coherence when it’s reviewed thoroughly by someone else. So.
Glen argues two things:
Timely code review is crucial to feature throughput of a team.
This article hit home when Glen wrote this:
Pending code review represent blocked threads of execution. … In the best case, an engineer blocked on code review is able to make progress on some other change, at the cost of (1) context switching and (2) increased memory allocation. … In the worst case, an engineer blocked on code review can’t make any progress at all, because the work allocated to them is serialized on the review.
All the allegories to computers aside, this is exactly my frustration as a programmer. I tend to do 10 or 12 different things because I get blocked on code review. Then a month goes by and I forget to ping the reviewers again and oh goodness now the code is totally outdated and I may as well give up. Wasted work!
Glen also makes the case that we should review others’ code promptly. “Expect to spend time on code review every day, throughout the day,” he writes. Shortening iterations between reviewing, responding to review, and re-reviewing can drastically increase work throughput of the team.