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Re: [PATCH] Lengthening FORMAT_PATCH_NAME_MAX to 80

From
Junio C Hamano <gitster@pobox.com>
Date
Nov 5, 2020, 21:16 UTC
Message-ID
<xmqqimajijwa.fsf@gitster.c.googlers.com>
In-Reply-To
<20201105150149.GA107127@coredump.intra.peff.net>
Jeff King <peff@peff.net> writes:
Show 25 quoted lines
>> 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.

Show 15 quoted lines
> 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.
Previous: Jeff KingNext: hukeping
Message 3 of 15 in “Lengthening FORMAT_PATCH_NAME_MAX to 80”
  1. Lengthening FORMAT_PATCH_NAME_MAX to 80Hu Keping, Nov 5, 2020
  2. Jeff KingNov 5, 2020
  3. Junio C HamanoNov 5, 2020
  4. hukepingNov 6, 2020
  5. Junio C HamanoNov 6, 2020
  6. Junio C HamanoNov 6, 2020
  7. format-patch: make output filename configurableJunio C Hamano, Nov 6, 2020
  8. Eric SunshineNov 6, 2020
  9. format-patch: make output filename configurableJunio C Hamano, Nov 9, 2020
  10. Jeff KingNov 10, 2020
  11. Junio C HamanoNov 10, 2020
  12. hukepingNov 10, 2020
  13. Junio C HamanoNov 10, 2020
  14. hukepingNov 10, 2020
  15. Junio C HamanoNov 10, 2020

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