Re: [PULL REQUEST] Please pull rdma.git

[Robert LeBlanc <robert-4JaGZRWAfWbajFs6igw21g@public.gmane.org>]

On Tue, Jul 18, 2017 at 1:26 PM, Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> wrote:
> On Tue, Jul 18, 2017 at 12:07 PM, Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>>
>> Fair enough.  My branch still had two unpulled commits and was based on
>> v4.12-rc3.  But, you had already taken the SELinux/RDMA patches through
>> the SELinux tree during this merge window, and two of the fix  patches
>> in my pull request would have produced conflicts for you if I didn't
>> merge up to a common ancestor that had the SELinux/RDMA patches prior
>> to applying those patches to my tree (these two in particular):
>
> Please don't worry about conflicts, unless they are something really
> really fundamentally hard to merge. And even then, for rdma, I
> probably want to see them, just to see what the hell went wrong *this
> time*.
>
>>> And if the only reason for that merge is "sync with upstream", then
>>> no, that is not a sufficient reason. It has to have an actual real
>>> reason, and it needs to be stated.
>>
>> Does this apply to the for-next area as well?
>
> Largely, yes. Because the further away "for-next" gets from what you
> then eventually send me, if your for-next branch has odd useless
> merges, then either what you send me will have them too, or what you
> send me will be something entirely different and rebased.
>
> Basically, "automated merges" is wrong and bad. The ACPI people used
> to do them, and at some point their pull requests had more merge
> commits than they had actual changes.
>
> Merges should be generally *minimized*. They make it much harder to
> see what is actually your new independent work, and what is work that
> is on top of random other things.
>
> Regular automated merges is exactly the wrong thing to do, because it
> basically guarantees that you don't have a nice stand-alone
> development series (everything you do will be punctuated by those
> merges), _and_ that the merge commits are bad and have no good reason
> for them.
>
> Finally, the merges have a fundamental problem that is from past
> problems with rdma - in particular the history of mixing stuff up and
> having teams within one single company not even being able to talk or
> synchronize with each other.
>
> If you need merges for conflict resolution, it indicates to me that
> rdma *still* has that issue where people fight over the direction and
> the drivers between different teams.
>
> So while merges in general are something that should be avoided, when
> it comes to rdma in _particular_ I don't like seeing them, because I
> get the feeling that they are papering over the nasty development
> problems you guys have had, and are done as a way to handle the
> conflicts that were due to bad hygiene.
>
> So the *one* kind of merge that is good is the "development of this
> topic branch is finished and done, let's merge it up". But that is
> never about time, that's about "I'm done with this series, it's good
> to go into my main branch". That's a "forward merge", where you really
> merge the new and finished development tree into the base.
>
> The back-merges, when you merge some unrelated development, is
> generally a bad sign. It inevitably happens for various reasons, but
> it should be seen as the exception, not the rule, and it should
> *always* have an explanation.
>
>                       Linus
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

I'm trying to understand why merges are being done instead of rebases.
Since we don't want to include other people's work, it seems that it
is cleaner to do a rebase. This is more for my education with using
Git with such a large project rather than me suggesting something
useful. (I dropped Linus from this part of the thread so as not to
bother him with an off-topic conversation).

Thanks,
Robert

----------------
Robert LeBlanc
PGP Fingerprint 79A2 9CA4 6CC4 45DD A904  C70E E654 3BB2 FA62 B9F1
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html