Open Stack

On 06/24/2013 06:15 PM, Monty Taylor wrote:
>
>
> On 06/24/2013 05:56 PM, Mark McLoughlin wrote:
>> On Mon, 2013-06-24 at 22:50 +0100, Mark McLoughlin wrote:
>>> Hey,
>>>
>>> Pulling this out of gerrit for discussion.
>>>
>>> Background is one of my patches to diskimage-builder was -1ed because I
>>> terminated the title line of the commit message with a period:
>>>
>>>    https://review.openstack.org/33262
>>>
>>> This is actually the exact opposite to what I consider normal practice
>>> for git commit messages as I explained in the review and the tripleo
>>> wiki page, so I proposed a hacking change here:
>>>
>>>    https://review.openstack.org/33789
>>>
>>> The rationale for *not* having a period is:
>>>
>>>    * With the 50 char limit, space is at a premium on the first line
>>>
>>>    * The first line is often used as the Subject: in [PATCH] emails -
>>>      subject lines in emails generally don't end in a period
>>>
>>>    * Examples in:
>>>
>>>        https://wiki.openstack.org/wiki/GitCommitMessages#Summary_of_GIT_commit_message_structure
>>>
>>>      don't end in period
>>>
>>>      (Note - the "should not end with a period" was only added by me
>>>      recently)
>>>
>>>    * Another common reference on git commit messages
>>>
>>>        http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html doesn't either
>>>
>>>    * In git's own git repo, 1.43% of commit messages in the last year
>>>      ended in a period
>>>
>>>    * I'm not aware of any other OpenStack project which enforces this.
>>>      Looking at the history of various projects for the past year (and
>>>      excluding merge commits which don't end with a period), the use of
>>>      period termination runs at between 10 and 30%.
>>>
>>> Unlike other nitpicking I tend to do with commit messages, I previously
>>> never thought this was worth even mentioning to committers but if some
>>> reviewers were going to start -1ing people for the *correct* style then
>>> I figured it was best to clear it up.
>>>
>>> Now, for Robert's comments in the review:
>>>
>>>> It would have been nice for this to be discussed rather than dropping
>>>> into the communal standards without warning;
>>>
>>> I tried my best do explain why period termination is broken in the
>>> diskimage-builder review and wiki page, so it's not like I was trying to
>>> avoid a discussion.
>>>
>>> In any case, if I, jogo and sdague got this wrong somehow, the mistake
>>> is only a git-revert away from being corrected.
>>>
>>>> the prior documentation *did not* require a period,
>>>
>>> Yes, but the examples didn't use a period which obviously means a policy
>>> to *require* a period is a bit bizarre.
>>>
>>> I'm pretty confident that danpb didn't mention this when he wrote the
>>> page because he either felt it was obvious or not worth mentioning. I've
>>> cc-ed him to be sure.
>>>
>>>> and the reference that was sourced that
>>>> doesn't use them is one in the git-via-email world which is not how
>>>> OpenStack does *any* of it's git communications, so the 'gets used
>>>> like subject line of emails' point is entirely irrelevant.
>>>
>>> git was born came from a git-via-email world and its usage conventions
>>> reflect that. I raised the subject line point to try and explain how git
>>> conventions may have arisen.
>>>
>>>> In TripleO we have been using a period because the first line of the
>>>> commit message acts like the first line of a docstring: it is a pithy
>>>> description of the object it describes. Docstrings are also space
>>>> limited, and yet PEP8 happily requires good sentence structure and
>>>> grammar there.
>>>
>>> It's not a docstring, though. It's a git commit message.
>>>
>>>> tl;dr - this is an unpythonic change, and the lack of discussion is
>>>> quite annoying.
>>>
>>> Well, the former point is irrelevant and hopefully this email corrects
>>> the latter point :)
>>
>> I missed this point:
>>
>>> Also not that space is limited to 50 characters by choice, not
>>> necessity (the very same external reference about git commit messages
>>> pointed out that 50 is not a hard limit). It is a hard limit for us...
>>> because we chose to make it so.
>>
>> It's another pretty common git usage convention - I think the idea is to
>> make output like 'git log --oneline' fit on 80 char terminals. The
>> numbers don't add up, though, so maybe it's another thing from the
>> git-via-email world. Also, the idea is probably to take into account
>> that the first line can be quoted by e.g. 'Merge "foo"' or 'Revert
>> "foo"' in the first line of other commit messages.
>
> Long commit messages also look like poop in gerrit, and I don't think
> anyone cares enough about bucking this style thing to go write Java to
> fix it.
>
> 50 chars is common enough that vim syntax highlighting groks it. I see
> no reason to choose a different thing.
>
> Why 50? NO CLUE

As long as it gets auto enforced in hacking, I'll adapt to whatever. I 
admit I've been bleeding my first line to 72 characters recently as I 
wasn't sure we were still enforcing at 50. But I'm adaptable to 50. 
Makes you get to the point with that first line.

	-Sean

-- 
Sean Dague
http://dague.net