Latest commit de6144d Apr 30, 2015 @henrik henrik Tweak
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Code review guidelines

We review all code commit-by-commit after the fact using Remit.

Committers and reviewers should read these guidelines to do it better.


As a reviewer and committer both

Change medium if you talk past each other.

If you think you might be talking past each other, stop writing low-context, low-bandwidth comments. Talk IRL or over voice or video instead.

Don't have style debates.

Pointing out a difference in style is fine: it can help us learn from each other.

But don't let it go beyond pointing out the difference and saying "cool, I'll try that" or "thanks, but I prefer it this way".

If you feel strongly enough to want to advocate "your" style beyond this, propose a change in our styleguide and have the discussion on that pull request.

As a reviewer

Don't mention small style changes.

For small, mostly unimportant stylistic matters like quote style and whitespace, don't point them out unless that person has said they want that feedback.

It takes more time for the committer to open that project, find the file file and fix the quote style from ' to " than it's worth.

Fix it yourself or let it go.

We still have a "right" way of doing things: do complain if someone intentionally changes from the "right" to the "wrong" style, and please clean it up if you see it. It's just not efficient to enforce this in commit-by-commit review.

Don't mention harmless typos/grammar in internal docs or code comments.

Runnable code and customer-facing copy should not have typos or grammar errors.

But if someone makes a harmless typo or grammar error in internal docs or code comments, it probably takes more time for them to open that project, find the file and fix it than it's worth.

Fix it yourself or let it go.

Do point out if documentation is hard to understand or misleading, though, whether or not it has typos.

As a committer

Obey the styleguide.

If someone points out a styleguide violation, fix it. If you want to debate it, take that debate to the styleguide – after fixing it.

Don't obey comments you don't understand or agree with.

Every review comment should be seen as a suggestion. Don't follow them blindly because of things like the reviewer's seniority.

Ask questions (in person, if that helps) until you understand and agree that the change would be an improvement.

If you don't understand their point, don't change it until you do.

If you understand and still disagree, don't change it.

Understanding their point means understanding the underlying reasons this would be good or bad ("not DRYing this up could easily lead to bugs here"). An appeal to authority ("DHH says this is the right way") or to rules or smells ("this is not DRY", "this violates SRP") is not enough.

Don't spend much time on things you've already considered.

If you already thought of but rejected something that a reviewer suggests, feel free to skip it with a quick explanation, or even without one.

We want to keep review low-cost: you don't need to spend time justifying every decision.

If you're asked for clarification, clarify in the source.

If a reviewer asks what a piece of documentation or a snippet of code means, don't just reply in the review tool; try to clarify the documentation or code itself.

A reply in the review tool is hard to dig up later, if you even know to try.

Clarified code, on the other hand, helps everyone who deals with that code in the future.

One of the big wins of code review is to catch hard-to-understand things when someone still understands it (having just written it).