Re: Proposal: Add review tags to patch review workflow.

[Elena Zannoni <ezannoni@gmail.com>]

One thing to do possibly is to take a look at what the kernel does in
this area, with the tags for inspiration:
https://www.kernel.org/doc/html/latest/process/submitting-patches.html
(middle of the page).

The key-signed patch workflow is also worth looking at to implement.

elena


On 9/26/22 9:59 AM, Luis Machado via Gdb wrote:
> Hi Bruno,
> 
> Thanks for putting this together. I think this is an improvement to the
> current review workflow, and I
> think it would be a positive update.
> 
> On 9/21/22 12:04, Bruno Larsen via Gdb wrote:
>> TL;DR: I want to introduce the usage of 3 new review tags to the GDB
>> patch review workflow. They are: Reviewed-by, Approved-by and Tested-by.
>>
>> * Reviewed-by would be used by reviewers such as myself, who may look
>> over the code but don't have the authority to approve it for pushing,
>> essentially working as a +1.
>>
>> * Approved-by would be used by maintainers who have the authority to
>> approve code for pushing when they want to do so. Referenced as a +2
>> later in this email.
>>
>> * Tested-by would be used by new contributors or reviewers who aren't
>> familiar with the code touched by a given patch, but who are able to
>> verify that the test doesn't introduce regressions.
>>
>> I will now dive into motivation and specifics of the proposal.
>>
>> ----
>>
>> Motivation: As a new contributor, I see 4 main issues with the current
>> patch review workflow:
>>
>> 1. It is sometimes hard to be sure that the reviewer has approved your
>> patch, exemplified by a few recent patches which were already approved
>> and were still pinged by their authors, such as
>> https://sourceware.org/pipermail/gdb-patches/2022-August/191474.html
>> 2. Patch review as it is now looks rather thankless. Sometimes a patch
>> may go through various rounds of review, taking a lot of time from the
>> contributor and reviewer, but if the latter never suggested enough
>> code to warrant a Co-Authored-By tag, the only person mentioned at the
>> final commit will be the original writer. I have personally wanted to
>> thank reviewers who were especially helpful in understanding issues.
>> 3. As a new contributor, it is not always obvious when a LGTM means
>> the patch can be pushed. While one can always check the maintainers
>> file, it would be nice if this information was baked into a review.
>> 4. On the other hand, it's not always obvious to new reviewers
>> (non-approvers) that their LGTM makes any difference, possibly
>> discouraging them from giving positive feedback and making the
>> community feel less lively than it is.
>>
>> Adding Reviewed-by (R-b) tags by itself would solve the first 2
>> issues, since it only is given once the review is finished and the
>> patch is good to go from the reviewer's perspective. Approved-by (A-b)
>> tags were mentioned during the GDB BoF at Cauldron 2022, as a way to
>> fix issues 3 and 4, along with allowing for maintainers to give only
>> +1, instead of +2, when they are not sure about a certain change.
>> Tested-by (T-b) were also mentioned at the BoF as a way to give
>> another option for new reviewers, especially if they have different
>> hardware or setups.
>>
>>
>> The workflow: The basic usage is as simple as I explained above, if
>> all a reviewer is comfortable with doing is confirming that the error
>> is fixed and testing for regression, they can reply with a T-b tag; if
>> they are comfortable sharing a positive opinion on the proposed code,
>> but can't approve or are not sure if the patch should be approved,
>> they can reply with an R-b tag; and if they wish to approve a patch,
>> they reply with A-p.
>>
>> Questions arose when thinking of new versions of a given patch. The
>> workflow used by Glibc, which inspired great part of this proposal,
>> makes it so the tags are dropped only when a patch has been
>> "sufficiently changed". Cosmetic things like fixing typos or moving a
>> proposed function from one place to another would not invalidate R-b
>> tags, while reworking the solution would. The submitter has some space
>> to decide that they think the patch has changed enough to warrant a
>> new review (and invalidate the previous R-b), or the reviewer may ask
>> their tag to be removed if they disagree with a change.
>>
>> In case the explanation is not clear, the follow example shows how
>> these would be used in a fictional patch that requires 3 versions
>> before it is ready.
>>
>> ---
>>
>> From: new<at>contributor<dot>com
>> Subject: [PATCH] Fix GDB's behavior
>>
>> I fixed bug number PR/XXXXX by making GDB kick and scream instead of
>> failing silently.
>>
>> ---
>>
>> From: new<at>reviewer<dot>com
>> Subject: Re: [PATCH] Fix GDB's behavior
>>
>> I'm not sure how good this solution is, but I verified that in my
>> setup this doesn't regress anything and fixes the issue.
>> Tested-by: New Reviewer <new<at>reviewer<dot>com>
>>
>> ---
>>
>> From: other<at>reviewer<dot>com
>> Subject: Re: [PATCH] Fix GDB's behavior
>>
>> The solution looks good, but I have some style nits, see below.
>>
>> ---
>>
>> From: new<at>contributor<dot>com
>> Subject: [PATCHv2] Fix GDB's behavior
>>
>> I fixed bug number PR/XXXXX by making GDB kick and scream instead of
>> failing silently.
>> Tested-by: New Reviewer <new<at>reviewer<dot>com>
>>
>> ---
>>
>> From: other<at>reviewer<dot>com
>> Subject: Re: [PATCHv2] Fix GDB's behavior
>>
>> Thanks, this looks good now!
>>
>> Reviewed-by: Other Contributor <other<at>contributor<dot>com>
>>
>> ---
>>
>> From: approver<at>gdb<dot>com
>> Subject: [PATCHv2] Fix GDB's behavior
>>
>> I don't think this is a good solution, because you haven't fixed the
>> problem, just complained about it. Please ensure that the patch makes
>> GDB behave correctly with this input, though I'm not opposed to
>> keeping the warning for other unexpected errors.
>>
>> ---
>>
>> From: new<at>contributor<dot>com
>> Subject: [PATCHv3] Fix GDB's behavior
>>
>> I fixed bug number PR/XXXXX by making GDB work as expected, and also
>> added a warning for unexpected inputs.
>>
>> ---
>>
>> From: other<at>maintainer<dot>com
>> Subject: Re: [PATCHv3] Fix GDB's behavior
>>
>> Hi! This patch still looks good.
>> R-b: Other Maintainer <other<at>maintainer<dot>com>
>>
>> ---
>>
>> From: approver<at>gdb<dot>com
>> Subject: Re: [PATCHv3] Fix GDB's behavior
>>
>> I like this solution much better, thank you!
>> Approved-by: Approver <approver<at>gdb<dot>com>
>>
>> ---
>>
>> From: new<at>contributor<dot>com
>> Subject: Re: Re: [PATCHv3] Fix GDB's behavior
>>
>> Thank you, I pushed it!
>>
>