[llvm-dev] [RFC] High-Level Code-Review Documentation Update

[Chris Lattner via llvm-dev]

This looks really great to me Hal, thank you for improving this critical aspect of the community processes!

-Chris

> On Nov 14, 2019, at 7:46 PM, Finkel, Hal J. via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> Hi, everyone,
> 
> I've been fielding an increasing number of questions about how our 
> code-review process in LLVM works from people who are new to our 
> community, and it's been pointed out to me that our documentation on 
> code reviews is both out of date and not as helpful as it could be to 
> new developers.
> 
>   http://llvm.org/docs/DeveloperPolicy.html#code-reviews
> 
> I would like to compose a patch to update this, but before I do that, I 
> want to highlight some of my thoughts to get feedback. My intent is to 
> capture our community best practices in writing so that people new to 
> our community understand our processes and expectations. Here are some 
> things that I would like to capture:
> 
>  1. You do not need to be an expert in some area of the compiler to 
> review patches; it's fine to ask questions about what some piece of code 
> is doing. If it's not clear to you what is going on, you're unlikely to 
> be the only one. Extra comments and/or test cases can often help (and 
> asking for comments in the test cases is fine as well).
> 
>  2. If you review a patch, but don't intend for the review process to 
> block on your approval, please state that explicitly. Out of courtesy, 
> we generally wait on committing a patch until all reviewers are 
> satisfied, and if you don't intend to look at the patch again in a 
> timely fashion, please communicate that fact in the review.
> 
>  3. All comments by reviewers should be addressed by the patch author. 
> It is generally expected that suggested changes will be incorporated 
> into the next revision of the patch unless the author and/or other 
> reviewers can articulate a good reason to do otherwise (and then the 
> reviewers must agree). If you suggest changes in a code review, but 
> don't wish the suggestion to be interpreted this strongly, please state 
> so explicitly.
> 
>  4. Reviewers may request certain aspects of a patch to be broken out 
> into separate patches for independent review, and also, reviewers may 
> accept a patch conditioned on the author providing a follow-up patch 
> addressing some particular issue or concern (although no committed patch 
> should leave the project in a broken state). Reviewers can also accept a 
> patch conditioned on the author applying some set of minor updates prior 
> to committing, and when applicable, it is polite for reviewers to do so.
> 
>  5. Aim to limit the number of iterations in the review process. For 
> example, when suggesting a change, if you want the author to make a 
> similar set of changes at other places in the code, please explain the 
> requested set of changes so that the author can make all of the changes 
> at once. If a patch will require multiple steps prior to approval (e.g., 
> splitting, refactoring, posting data from specific performance tests), 
> please explain as many of these up front as possible. This allows the 
> patch author to make the most-efficient use of his or her time.
> 
>  6. Some changes are too large for just a code review. Changes that 
> should change the Language Reference (e.g., adding new 
> target-independent intrinsics), adding language extensions in Clang, and 
> so on, require an RFC on *-dev first. For changes that promise 
> significant impact on users and/or downstream code bases, reviewers can 
> request an RFC (Request for Comment) achieving consensus before 
> proceeding with code review. That having been said, posting initial 
> patches can help with discussions on an RFC.
> 
> Lastly, the current text reads, "Code reviews are conducted by email on 
> the relevant project’s commit mailing list, or alternatively on the 
> project’s development list or bug tracker.", and then only later 
> mentions Phabricator. I'd like to move Phabricator to be mentioned on 
> this line before the other methods.
> 
> Please let me know what you think.
> 
> Thanks again,
> 
> Hal
> 
> -- 
> Hal Finkel
> Lead, Compiler Technology and Programming Languages
> Leadership Computing Facility
> Argonne National Laboratory
> 
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