Code review

This page documents code review practices used for Software Heritage development.

WORK IN PROGRESS page

Guidelines

Code reviews (CRs) are strongly recommended for any non-trivial code change, but not mandatory (nor enforced at the VCS level).
The CR workflow is implemented using Phabricator/Differential.
Explicitly suggest reviewer(s) when submitting new CR requests: either the most knowledgeable person(s) for the target code or the general Reviewers group (which is also the default).
Review anything you want: no matter the suggested reviewer(s), feel free to review any outstanding CR.
One LGTM is enough: feel free to approve any outstanding CR.
Review every day: CRs should be timely as fellow developers will wait for them. To make CRs team-sustainable each developer should allocate a fixed minimum amount of time for doing CR every (work ☺) day.

For more detailed suggestions (and much more) on the motivational and practical aspects of code reviews see Good reads below.

Good reads on various angles of code review:

Best practices (Palantir) ← comprehensive and recommended read, especially if you're short on time
Best practices (Thoughtbot)
Review checklist (Code Project)
Motivation: team culture (Google & FullStory)
Motivation: code quality (Coding Horror)
Motivation: humanizing peer reviews (Wiegers)