git commit message conventions

[Joseph Myers]

On Wed, 3 Jun 2015, Ondøej Bílka wrote:

> Correct, I just use script to add bug in NEWS and open bugzilla window so that
> isn't as much problem. Changelogs are likewise generated most of time, I
> dont have script to extract it from mail, does anybody have one?
>  As far as I recall discussion only Roland found changelogs useful,
> otherwise it was inertia.

I find ChangeLog messages are useful in some cases as a table of contents 
to the patch, for those patches where a ChangeLog entry relates 
meaningfully to the level at which the patch operates (not for a global 
change across many files, not for a change rearranging things so a 
description in terms of individual named entities is at the wrong level to 
describe the rearrangement).

I don't think it's particularly useful to have separate ChangeLogs for 
localedata and libidn.  I think it would be fine to have a system that 
generates ChangeLogs for release tarballs from git logs (of course this 
would mean "git archive" could no longer be used), provided it supports 
multi-author changes and corrections to the logs (including author and 
date) for past changes, even if it doesn't support putting things in three 
separate ChangeLogs.  (We'd also need to work out how it should handle 
merges, though we generally discourage merge commits on master for most 
trivial merge cases.)

I think it would be fine to have a system to extract the list of fixed 
bugs from Bugzilla at release time (I'm supposing someone would run a 
script and then put the list in NEWS manually and check in the change, 
with subsequent corrections to that list being done manually as well), 
which would need a convention for how you record the fixed version / 
versions in Bugzilla in a searchable way and people watching that this 
gets set when marking bugs fixed.

But my present proposal is for a more limited incremental change: don't 
use a single-line commit message with a more substantial write-up in the 
libc-alpha email, put the libc-alpha email contents in the commit message 
instead.  If you wish to format your commit message so it has a more 
fully-defined relation to the ChangeLog entry, that's entirely fine by my 
proposal, just not required.

-- 
Joseph S. Myers
joseph@codesourcery.com