Re: [PATCH v2 1/2] format-patch: Add a config option format.from to set the default for --from

[Jeff King <peff@peff.net>]

On Sun, Aug 07, 2016 at 06:42:07PM -1000, Josh Triplett wrote:

> > Drop trailing comma after the last enum definition (trailing comma
> > after the last element in an array is OK, though).
> 
> I realize this code didn't get included in the final version, but for
> future reference, what's the rationale for this?  I tend to include a
> final comma in cases like these (and likewise for initializers) to avoid
> needing to change the last line when introducing a new element, reducing
> noise in diffs.  I hadn't seen anything in any of the coding style
> documentation talking about trailing commas (either pro or con).

Portability; some compilers choke on it. C89 allows trailing commas in
array initialization but _not_ in enums. Most compilers allow it anyway
(though gcc complains with -Wpedantic).

This definitely broke the build on real systems early in Git's history
(I think the AIX compiler was one culprit), but at this point it's
possible that all of those compilers have died off. It would be nice if
we could start using it (for exactly the reasons you give).
Unfortunately there's not a good way to know except "introduce it and
see if people complain".

-Peff