Re: [PATCH] checkpatch: Add test for commit id formatting style in commit log

From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Aug 10, 2014, 21:08 UTC
Message-ID: <CAMuHMdV1TXLmuAofwrUuT-KKUfkEYdXsM34VRrfhB6FxXfdeeg@mail.gmail.com>
In-Reply-To: <1404338448.14741.8.camel@joe-AO725>

Hi Joe,

On Thu, Jul 3, 2014 at 12:00 AM, Joe Perches <joe@perches.com> wrote:

Show 7 quoted lines

> Commit logs have various forms of commit id references.
>
> Try to standardize on a 12 character long lower case
> commit id along with a description of parentheses and
> the quoted subject line
>
> ie: commit 0123456789ab ("commit description")

Now this is in mainline, checkpatch starts complaining about my "too long" (40 chars) commit IDs in commit messages :-(

40 chars may be too long (but it's quick to copy-and-paste, as "git show" shows that by default), but 12 sounds a bit short, as that's only 48 bits.

According to the Birthday Paradox (en.wikipedia.org/wiki/Birthday_problem), there's a probability of 50% of a collision if you use 48 bits IDs in a repository with ca. 16 milion (2^24) objects. A Linux kernel repository counts ca. 4 million objects, so we're getting close...

So soon we'll get "error: short SHA1 is ambiguous".

BTW, is there actually an easy way to make "git show" show all options for an ambiguous SHA1?

Gr{oetje,eeting}s,

                        Geert

-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds