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diff --git a/Documentation/ReviewingGuidelines.txt b/Documentation/ReviewingGuidelines.txt new file mode 100644 index 0000000..515d470 --- /dev/null +++ b/Documentation/ReviewingGuidelines.txt @@ -0,0 +1,162 @@ +Reviewing Patches in the Git Project +==================================== + +Introduction +------------ +The Git development community is a widely distributed, diverse, ever-changing +group of individuals. Asynchronous communication via the Git mailing list poses +unique challenges when reviewing or discussing patches. This document contains +some guiding principles and helpful tools you can use to make your reviews both +more efficient for yourself and more effective for other contributors. + +Note that none of the recommendations here are binding or in any way a +requirement of participation in the Git community. They are provided as a +resource to supplement your skills as a contributor. + +Principles +---------- + +Selecting patch(es) to review +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If you are looking for a patch series in need of review, start by checking +the latest "What's cooking in git.git" email +(https://lore.kernel.org/git/xmqqilm1yp3m.fsf@gitster.g/[example]). The "What's +cooking" emails & replies can be found using the query `s:"What's cooking"` on +the https://lore.kernel.org/git/[`lore.kernel.org` mailing list archive]; +alternatively, you can find the contents of the "What's cooking" email tracked +in `whats-cooking.txt` on the `todo` branch of Git. Topics tagged with "Needs +review" and those in the "[New Topics]" section are typically those that would +benefit the most from additional review. + +Patches can also be searched manually in the mailing list archive using a query +like `s:"PATCH" -s:"Re:"`. You can browse these results for topics relevant to +your expertise or interest. + +If you've already contributed to Git, you may also be CC'd in another +contributor's patch series. These are topics where the author feels that your +attention is warranted. This may be because their patch changes something you +wrote previously (making you a good judge of whether the new approach does or +doesn't work), or because you have the expertise to provide an exceptionally +helpful review. There is no requirement to review these patches but, in the +spirit of open source collaboration, you should strongly consider doing so. + +Reviewing patches +~~~~~~~~~~~~~~~~~ +While every contributor takes their own approach to reviewing patches, here are +some general pieces of advice to make your reviews as clear and helpful as +possible. The advice is broken into two rough categories: high-level reviewing +guidance, and concrete tips for interacting with patches on the mailing list. + +==== High-level guidance +- Remember to review the content of commit messages for correctness and clarity, + in addition to the code change in the patch's diff. The commit message of a + patch should accurately and fully explain the code change being made in the + diff. + +- Reviewing test coverage is an important - but easy to overlook - component of + reviews. A patch's changes may be covered by existing tests, or new tests may + be introduced to exercise new behavior. Checking out a patch or series locally + allows you to manually mutate lines of new & existing tests to verify expected + pass/fail behavior. You can use this information to verify proper coverage or + to suggest additional tests the author could add. + +- When providing a recommendation, be as clear as possible about whether you + consider it "blocking" (the code would be broken or otherwise made worse if an + issue isn't fixed) or "non-blocking" (the patch could be made better by taking + the recommendation, but acceptance of the series does not require it). + Non-blocking recommendations can be particularly ambiguous when they are + related to - but outside the scope of - a series ("nice-to-have"s), or when + they represent only stylistic differences between the author and reviewer. + +- When commenting on an issue, try to include suggestions for how the author + could fix it. This not only helps the author to understand and fix the issue, + it also deepens and improves your understanding of the topic. + +- Reviews do not need to exclusively point out problems. Feel free to "think out + loud" in your review: describe how you read & understood a complex section of + a patch, ask a question about something that confused you, point out something + you found exceptionally well-written, etc. In particular, uplifting feedback + goes a long way towards encouraging contributors to participate more actively + in the Git community. + +==== Performing your review +- Provide your review comments per-patch in a plaintext "Reply-All" email to the + relevant patch. Comments should be made inline, immediately below the relevant + section(s). + +- You may find that the limited context provided in the patch diff is sometimes + insufficient for a thorough review. In such cases, you can review patches in + your local tree by either applying patches with linkgit:git-am[1] or checking + out the associated branch from https://github.com/gitster/git once the series + is tracked there. + +- Large, complicated patch diffs are sometimes unavoidable, such as when they + refactor existing code. If you find such a patch difficult to parse, try + reviewing the diff produced with the `--color-moved` and/or + `--ignore-space-change` options. + +- If a patch is long, you are encouraged to delete parts of it that are + unrelated to your review from the email reply. Make sure to leave enough + context for readers to understand your comments! + +- If you cannot complete a full review of a series all at once, consider letting + the author know (on- or off-list) if/when you plan to review the rest of the + series. + +Completing a review +~~~~~~~~~~~~~~~~~~~ +Once each patch of a series is reviewed, the author (and/or other contributors) +may discuss the review(s). This may result in no changes being applied, or the +author will send a new version of their patch(es). + +After a series is rerolled in response to your or others' review, make sure to +re-review the updates. If you are happy with the state of the patch series, +explicitly indicate your approval (typically with a reply to the latest +version's cover letter). Optionally, you can let the author know that they can +add a "Reviewed-by: <you>" trailer if they resubmit the reviewed patch verbatim +in a later iteration of the series. + +Finally, subsequent "What's cooking" emails may explicitly ask whether a +reviewed topic is ready for merging to the `next` branch (typically phrased +"Will merge to \'next\'?"). You can help the maintainer and author by responding +with a short description of the state of your (and others', if applicable) +review, including the links to the relevant thread(s). + +Terminology +----------- +nit: :: + Denotes a small issue that should be fixed, such as a typographical error + or misalignment of conditions in an `if()` statement. + +aside: :: +optional: :: +non-blocking: :: + Indicates to the reader that the following comment should not block the + acceptance of the patch or series. These are typically recommendations + related to code organization & style, or musings about topics related to + the patch in question, but beyond its scope. + +s/<before>/<after>/:: + Shorthand for "you wrote <before>, but I think you meant <after>," usually + for misspellings or other typographical errors. The syntax is a reference + to "substitute" command commonly found in Unix tools such as `ed`, `sed`, + `vim`, and `perl`. + +cover letter:: + The "Patch 0" of a multi-patch series. This email describes the + high-level intent and structure of the patch series to readers on the + Git mailing list. It is also where the changelog notes and range-diff of + subsequent versions are provided by the author. ++ +On single-patch submissions, cover letter content is typically not sent as a +separate email. Instead, it is inserted between the end of the patch's commit +message (after the `---`) and the beginning of the diff. + +#leftoverbits:: + Used by either an author or a reviewer to describe features or suggested + changes that are out-of-scope of a given patch or series, but are relevant + to the topic for the sake of discussion. + +See Also +-------- +link:MyFirstContribution.html[MyFirstContribution] |