Responsibilities of Committers and Reviewers

When you're committing to the chromium repositories, ensure that you follow those guidelines:

1. Find the right reviewer for your changes and for patches you're asked to review.
2. Use the Commit Queue to commit your change (by setting Commit-Queue +2 on the code review page). For exceptional cases where you might not use the CQ, see Directly committing code.
3. If you need to revert your change, use the Revert button on the code review page.
4. Some types of mechanical changes can be landed without requiring full owners approval. See Mechanical Changes docs.

In short, do the right thing for the project, not the easiest thing to get code committed, and above all: use your best judgement.

Don't be afraid to ask questions. There is always someone on Slack who can help you.

Changes with multiple reviewers

There are occasionally changes with a lot of reviewers on them, since sometimes several people might need to be in the loop for a change because of multiple areas of responsibility and expertise.

The problem is that without some guidelines, there's no clear responsibility given in these reviews.

If you're the sole reviewer on a change, you know you have to do a good job. When there are three other people, you sometimes assume that somebody else must have looked carefully at some part of the review. Sometimes all the reviewers think this and the change isn't reviewed properly.

In other cases, some reviewers say "LGTM" for a patch, while others are still expecting changes. The author can get confused as to the status of the review, and some patches have been checked in where at least one reviewer expected further changes before committing.

At the same time, we want to encourage many people to participate in the review process and keep tabs on what's going on.

So, here are some guidelines to help clarify the process:

1. When a patch author requests more than one reviewer, they should make clear in the review request email what they expect the responsibility of each reviewer to be. For example, you could write this in the email: larry: bitmap changes sergey: process hacks everybody else: FYI In this case, you might be on the review list because you've asked to be in the loop for multiprocess changes, but you wouldn't be the primary reviewer and the author and other reviewers wouldn't be expecting you to review all the diffs in detail.
2. If you get a review that includes many other people, and the author didn't do (1), please ask them what part you're responsible for if you don't want to review the whole thing in detail.
3. The author should wait for approval from everybody on the reviewer list before checking in.
4. People who are on a review without clear review responsibility (i.e. drive-by reviews) should be super responsive and not hold up the review. The patch author should feel free to ping them mercilessly if they are.
5. If you're an "FYI" person on a review and you didn't actually review in detail (or at all), but don't have a problem with the patch, note this. You could say something like "rubber stamp" or "ACK" instead of "LGTM." This way the real reviewers know not to trust that you did their work for them, but the author of the patch knows they don't have to wait for further feedback from you. Hopefully we can still keep everybody in the loop but have clear ownership and detailed reviews. It might even speed up some changes since you can quickly "ACK" changes you don't care about, and the author knows they don't have to wait for feedback from you.