[llvm-dev] [cfe-dev] Phabricator -> GitHub PRs?

Emilio Cobos Álvarez via llvm-dev llvm-dev at lists.llvm.org
Wed Jan 15 11:37:19 PST 2020

On 1/15/20 8:30 PM, David Greene wrote:
> Emilio Cobos Álvarez <emilio at crisal.io> writes:
>> [1] or [2] are recentish examples that come to mind, but it happens
>> fairly often. Of course for a bunch of simpler changes one revision is
>> enough.
> I think you forgot to include links.  :)

Whoopsies :-)

 * https://bugzilla.mozilla.org/show_bug.cgi?id=1449861
 * https://bugzilla.mozilla.org/show_bug.cgi?id=1503656

>> The use cases are similar to the "I have one PR with multiple commits"
>> in GitHub, but with the advantage of being able to review them
>> individually, and thus they can land upstream sooner.
> Downstream we strongly suggest people use a one-commit-per-PR model.
> That does incur some additional overhead but I personally haven't found
> it to be an issue.  Usually if I have a series of dependent patches,
> then I need to merge the first one before I can do the second one, etc.
> I can see how having multiple patches up at once for review might speed
> things up.  But what if a very first patch in a series needs major
> changes and that affects every single following patch?  The series has
> to be re-posted anyway, right?  I don't see how this is much better than
> reviewing the first patch and getting that merged first, moving on to
> the second patch, etc.
> If the patches truly are independent, then why not open a separate PR
> for each one?  Yes, with GitHub that requires a separate branch for each
> but if the changes are truly independent then multiple branches seems
> entirely appropriate to me.  IME it helps keep things organized.
> Independent changes are independent lines of development.  Changes
> needed for one don't affect the state of the others.
> If the patches are dependent, then we're back to the situation above
> where review causes the need to re-post a new version of the series.  If
> review goes smoothly then I guess maybe there is some time saved but how
> often does that really happen for any kind of large change that would be
> needed to be broken up into multiple commits?

I don't think you necessarily need to post a second version of each
patch in the series. At least I update changes individually. Some of the
changes on the bottom of the stack may require changes on the following
patches of course, but...

 -- Emilio

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