Re: [Qemu-devel] [PATCH] get_maintainer.pl: Default to --no-git-fallback

[Markus Armbruster <armbru@redhat.com>]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Tue, Oct 21, 2014 at 02:22:41PM +0200, Markus Armbruster wrote:
>> "Michael S. Tsirkin" <mst@redhat.com> writes:
>> 
>> > On Tue, Oct 21, 2014 at 11:31:12AM +0200, Markus Armbruster wrote:
>> >> "Michael S. Tsirkin" <mst@redhat.com> writes:
>> >> 
>> >> > On Mon, Oct 20, 2014 at 03:19:52PM +0100, Peter Maydell wrote:
>> >> >> On 20 October 2014 15:15, Michael S. Tsirkin <mst@redhat.com> wrote:
>> >> >> > On Mon, Oct 20, 2014 at 03:04:44PM +0100, Peter Maydell wrote:
>> >> >> >> On 20 October 2014 10:19, Markus Armbruster
>> >> >> >> <armbru@redhat.com> wrote:
>> >> >> >> > Contributors rely on this script to find maintainers to copy.  The
>> >> >> >> > script falls back to git when no exact MAINTAINERS pattern matches.
>> >> >> >> > When that happens, recent contributors get copied, which
>> >> >> >> > tends not be
>> >> >> >> > particularly useful.  Some contributors find it even annoying.
>> >> >> >> >
>> >> >> >> > Flip the default to "don't fall back to git".  Use
>> >> >> >> > --git-fallback to
>> >> >> >> > ask it to fall back to git.
>> >> >> 
>> >> >> >> Good idea.
>> >> >> 
>> >> >> > What do you want to happen in this case?
>> >> >> 
>> >> >> It should mail the people who are actually maintainers,
>> >> >> not anybody who happened to touch the code in the last
>> >> >> year.
>> >> >
>> >> > Right but as often as not there's no data about that
>> >> > in MAINTAINERS.
>> >> 
>> >> The way to fix that is finding maintainers, not scatter-shooting patches
>> >> to random contributors in the vague hope of hitting someone who cares.
>> >> 
>> >> >> > I'm yet to see contributors who are annoyed but we
>> >> >> > can always blacklist specific people.
>> >> >> 
>> >> >> At the moment I just don't use get_maintainers.pl at
>> >> >> all because I tried it a few times and it just cc'd
>> >> >> a bunch of irrelevant people...
>> >> >> 
>> >> >> I suspect anybody using it at the moment is either
>> >> >> using the --no-git-fallback flag or trimming the
>> >> >> cc list a lot.
>> >> >> 
>> >> >> thanks
>> >> >> -- PMM
>> >> >
>> >> > I'm using it: sometimes with --no-git-fallback, sometimes without.
>> >> 
>> >> I'm using it, but I absolutely want to know when it falls back to git,
>> >> because then I want to cheack and trim or ignore its output every single
>> >> time.
>> >
>> >
>> > Well it tells you the role. What else is necessary?
>> 
>> For my own use in sending patches, nothing.  I know how to use it to
>> help me copy the right people.
>> 
>> >> > IIUC the default is to have up to 5 people on the Cc list
>> >> > (--git-max-maintainers).
>> >> > It's not like it adds 200 random people, is it?
>> >> >
>> >> > Anyway experienced contributors can figure it out IMHO.
>> >> 
>> >> Experienced contributors can figure out --git-fallback, too.
>> >
>> > Exactly.
>> >
>> >> What we see is contributors, especially less experienced ones, copying
>> >> whatever get_maintainers.pl spits out, because they have no idea what
>> >> get_maintainers.pl actually does.
>> >
>> > Exactly. And this seems better than just sending to qemu ML
>> > and not copying anyone.
>> 
>> That's where we disagree.
>> 
>> Personally, I don't mind getting punished for contributing patches by
>> getting copied indiscriminately all that much.  It's a drain on my time,
>> but I can cope.  However, I know people who do mind, and some of them
>> have spoken up in this thread.
>> 
>> Copying people is not free.  You should *think* before you copy.
>> 
>> An entry in MAINTAINERS dispenses you from this obligation, because the
>> people listed explicitly asked for a copy.
>> 
>> Finding someone in git-log does not!
>> 
>> get_maintainers.pl encourages its users to treat people found in git-log
>> exactly like the ones in MAINTAINERS.  Treating them the same is
>> *wrong*.
>> 
>> >> > Question in my mind is what do we want a casual contributor
>> >> > to do if there's no one listed in MAINTAINERS.
>> >> > "Look in MAINTAINERS, if not there, look in git log"
>> >> > sounds very reasonable to me, better than "CC no one".
>> >> 
>> >> But that's not what we do!  We do "copy whatever get_maintainers.pl
>> >> coughs up", which boils down to "use MAINTAINERS, if not there, grab
>> >> some random victims from git-log".
>> >
>> > Sorry, what's the difference?
>> > "look in" versus "random victims"? what makes them random?
>> 
>> The difference is using get_maintainers.pl to help finding whom to copy
>> vs. blindly copying whoever get_maintainers.pl coughs up.
>> 
>> > Maybe you just want to increase git-min-percent?
>> >
>> >> Perhaps we'd get slightly better results if get_maintainers.pl told its
>> >> users clearly about the two kinds of output it may produce: maintainers
>> >> (must be copied on patches), and recent contributors (you're in trouble;
>> >> copying some of them may or may not help).
>> >
>> > That's what it does: it reports the role, and the percent.
>> 
>> Boldly assumes the user of get_maintainers.pl knows what it does, and
>> knows how to interpret runes like (commit_signer:14/22=64%).
>
> OK so you would like a flag for a more readable output?
> Sounds very reasonable.

Inexperienced contributors are unlikely to find a flag, so it better be
the default.

>> > What's missing?
>> 
>> What's really missing is decent coverage by MAINTAINERS.  I figure my
>> patch is controversial only because MAINTAINERS is so woefully
>> incomplete.
>
> In fact if MAINTAINERS covered everything your patch won't be needed
> right?

Correct.  The more MAINTAINERS covers, the less of a difference my patch
makes.

>> My patch to get_maintainers.pl triggered a whole thread, while the
>> message I sent on MAINTAINERS coverage got just one reply so far, and
>> even that one's really just about get_maintainers.pl.  Disappointing.
>> Looks like we're still looking for an easy technical fix.  I doubt there
>> is one.
>
> At least for myself, that's because I'm Cc'd directly on the patch
> but not on the MAINTAINERS coverage mail.
> And that's ... because get_maintainers picks my mail from git?
>
> See how it's useful now?

Except that's not what happened.

    $ scripts/get_maintainer.pl --git-fallback -f scripts/get_maintainer.pl 

No output.  I picked you from git-log manually.

>> If you have better ideas on how to mitigate the excessive and useless
>> copying we now see, please post a patch.
>
> We need more maintainers :)

Yes, we do.  Until we got them, we need fewer useless copies.