Re: [PATCH] Lengthening FORMAT_PATCH_NAME_MAX to 80

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

>> Considered the prefix patch number "0001-" would take 5 characters, increase
>> the FORMAT_PATCH_NAME_MAX to 80.
>
> As the code is written now, the length also includes the ".patch"
> suffix, as well as an extra byte (maybe for a NUL? Once upon a time I
> imagine we used static buffers, but these days it's all in a strbuf).
>
> A simple test with:
>
>   git init
>   for i in $(seq 8); do printf 1234567890; done |
>   git commit --allow-empty -F -
>   git format-patch -1
>
> shows us generating:
>
>   0001-1234567890123456789012345678901234567890123456789012.patch
>
> So that's only 52 characters, from our constant of 64. Bumping to 80
> gives us 66, which is reasonable though probably still involves
> occasional truncation. But maybe keeping the total length to 80 (79,
> really, because of the extra byte) may be worth doing.
>
> Which is all a long-winded way of saying that your patch seems
> reasonable to me.

A devil's advocate thinks that we should shorten it (and rename it
to format-patch-subject-prefix-length or something) instead.  That
way, "ls" output can show more than one files on a single line even
on a 80-column terminal.  The leading digits already guarantee the
uniqueness anyway.

I do not mind getting rid of the "FORMAT_PATCH_NAME_MAX" constant
and replacing it with a variable that defaults to 64 and can be
tweaked by a command line option and/or a configuration variable.
It does not feel it is worth the effort to replace one hardcoded
constant with another hardcoded constant.

> Looking at the code which uses the constant, I suspect it could also be
> made simpler:
>
>   - the PATH_MAX check in open_next_file() seems pointless. Once upon a
>     time it mattered for fitting into a PATH_MAX buffer, but these days
>     we use a dynamic buffer anyway. We are probably better off to just
>     feed the result to the filesystem and see if it complains (since
>     either way we are aborting; I'd feel differently if we adjusted our
>     truncation size)
>
>   - the logic in fmt_output_subject() could probably be simpler if the
>     constant was "here's how long the subject should be", not "here's
>     how long the whole thing must be".
>
> But those are both orthogonal to your patch and can be done separately.

Yes, these clean-ups seem worth doing.