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

Thu Jan 23 14:11:34 PST 2020

On Thu, Jan 23, 2020 at 9:30 AM Fedor Sergeev via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hubert, thank you so much for the detailed bisection of what I believe
> is the most
> problematic GitHub PR =<= Phab difference in terms of review process!
>

This thread has been focused on a specific aspect of the tooling / process,
the thread we had two months ago mentioned another important blocker which
was the support for Herald rules.

It is also quite possible that there are other issues, I would be cautious
at relying too much on the current thread to consider having an exhaustive
list of possible issues.

Best,

-- 
Mehdi

>
> Summarizing, I see two main pain points in GitHub PR experience as
> explained here
> that beg for improvement:
>   1. low information density of "conversation" view
>
>   2. inconvenient navigation/discovery of comments for multiple commits
> in presence of force push
>
> As I see it, these two points will constantly get in the way of review
> process for nontrivial
> patch series (and somehow I believe that quality of review for
> nontrivial patches will have the
> biggest impact on the quality of the project itself).
>
> Do we have a good reason to believe that LLVM as  a community has enough
> weight
> to nudge Github to really improve on these two points?
>
> If yes, then can we start moving there? File bugs or whatnot...
> It would be a very nontrivial effort for me to even describe the problem
> in comprehensible
> (and non-offensive ;)  way, so I know I'm asking somebody else to do the
> hard job.
>
> best regards,
>    Fedor.
>
> On 1/23/20 3:02 AM, Hubert Tong via llvm-dev wrote:
> > On Wed, Jan 22, 2020 at 5:19 PM David Greene <greened at obbligato.org
> > <mailto:greened at obbligato.org>> wrote:
> >
> >     Hubert Tong <hubert.reinterpretcast at gmail.com
> >     <mailto:hubert.reinterpretcast at gmail.com>> writes:
> >
> >     > It was already mentioned earlier in the thread that:
> >     > - The individual commits cannot be approved in the sense of
> >     approving a PR.
> >
> >     Later conversation makes me wonder how often that really happens
> >     though.
> >     In a true patch series I would think it would be very rare to be
> >     able to
> >     land a later commit before an earlier commit.
> >
> > I had provided the use case for a patch series where being able to do
> > so is possible (the case of related patches with little semantic
> > ordering but is high on syntactic merge conflicts). Whether or not
> > such a patch series qualifies as a "true" patch series might be a
> > philosophical discussion that could be had, but the practicality of
> > keeping a common dependency order was presented.
> >
> >
> >     > - Comments on individual commits are easily lost.
> >
> >     This is the piece that I feel needs more explanation.  What does
> >     "lost"
> >     mean, exactly?  I will comment more on your explanation below.
> >
> > "Lost" means that it becomes hard to find and track.
> >
> >
> >     > To elaborate on the latter:
> >     > - GitHub would not show comments in-line if it unilaterally
> >     believes that
> >     > the comment no longer applies to the version of the code you are
> >     looking at.
> >
> >     Ok, but doesn't Phab do the same?  Or does Phab attach the comment to
> >     some potentially completely inappropriate line?  The latter seems
> >     worse
> >     to me.
> >
> > Phab does the latter, but you can (1) find the comment, and (2) find
> > its original context. The fact that it was on an older version of the
> > code is expressed by the shading/colour and an icon. It does not make
> > the comment hard to find like GitHub does. At some point, if a force
> > push in involved, the GitHub comments for the "replaced" commits can
> > only be found in the long conversation view. You might have no chance
> > of seeing them presented in-line. In other words, if a single PR is
> > treated as a patch series, updating an early commit might orphan all
> > the in-line comments on the latter commits if a force push is used.
> >
> > The long conversation view suffers from low information density (needs
> > lots of scrolling) and for single-PR-as-patch-series means that
> > comments on different commits are interleaved. More to the point: The
> > long conversation view lacks focus and context.
> >
> > Replies to older comments in GitHub have a tendency to be hard to
> > notice as well. A comment that needs pinging because people missed it
> > the first time can be pinged using the reply functionality in Phab
> > effectively. Doing the same in GitHub might leave the ping someplace
> > where people won't see it unless if they were notified. Even if they
> > were notified, they might not be able to find it easily except through
> > the notification.
> >
> >
> >     > - GitHub would proactively hide and collapse comments in the
> >     "conversation
> >     > view", especially if it believes (for such bad reasons as line
> >     noise in
> >     > later commits) that an earlier comment is not relevant.
> >
> >     I'm reading this as comments aren't "lost" in the sense that they are
> >     completely deleted from the PR.
> >
> > Yes, but comments presented without any context is not great. Even if
> > the context has not been deleted due to force push, seeing older
> > comments in any sort of context using GitHub has required opening more
> > versions of the file in my experience than with Phab (where the
> > comments appear "near enough" fairly often).
> >
> >     They may be collapsed. What does
> >     "hide" mean?  Are they completely inaccessible?
> >
> > GitHub has several layers of making comments hard to find or notice.
> > Blocks of comments may become "hidden conversations" in the
> > conversation view (including completely new ones, e.g., if a reviewer
> > does their first pass over a patch and had a lot of comments to make).
> > This need to "load more" is presumably designed to save on server
> > bandwidth. Individual comments may be hidden (similar to collapsing
> > inline comments in Phab) as well (the comment text is folded away)
> > because they are presumably "outdated" or "resolved".
> >
> > With GitHub, "anyone" can cause comments to become less noticeable.
> > With Phab, it saves the state of whether inline comments are collapsed
> > by you for you.
> >
> >
> >     This is an important point.  If comments are simply collapsed and
> >     I can
> >     easily get at them if I need to, that's not too much of a problem for
> >     me.
> >
> > I have not found it to be easy to get to them. When requesting to
> > "show" everything, the hidden conversations remain hidden. I had to
> > scroll through and "load" the blocks one by one.
> >
> >     After all, Phab auto-hides comments all the time if the
> >     conversation gets "too long."
> >
> > Not the inline comments, and for inline comments, Phab includes a bit
> > of the comment even when collapsed. GitHub doesn't.
> >
> >       I am frequently annoyed by having to
> >     un-collapse them.  Sounds like I would be annoyed in the same way
> with
> >     GitHub, so nothing really gained or lost to me.
> >
> > Uncollapsing in Phab has been much easier for me than on GitHub. Also,
> > for similarly sized reviews, I've had to uncollapse on GitHub more
> > often than on Phab.
> >
> >
> >                              -David
> >
> >
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