On Sun, 2014-08-10 at 23:08 +0200, Geert Uytterhoeven wrote:
> Hi Joe,
Hi Geert.
> On Thu, Jul 3, 2014 at 12:00 AM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> > 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.
Right now, this test allows 12 to 16 byte length commit ids
without emitting a warning.
Andrew wanted this test, I don't care how long the commit id
is in the commit log.
> According to the Birthday Paradox (en.wikiipedia.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?
Not so far as I know, but I'm nothing like a git expert.
The script I used before adding this to checkpatch was:
$ cat format_commit.sh
#!/bin/bash
regex1="^error: short SHA1 $1 is ambiguous\."
regex2="fatal: ambiguous argument '$1': unknown revision or path not in the working tree\."
tmp=$(mktemp --tmpdir format_commit.XXXXXXXXXXXXX)
git log --format='%H ("%s")' -1 $1 > $tmp 2>&1
read line < $tmp
rm -f $tmp
if [[ $line =~ $regex1 ]] ; then
echo "checking commits $1..."
git rev-list --remotes | grep -i "^$1" |
while read line ; do
git log --format='%H ("%s")' -1 $line |
echo "commit $(cut -c 1-12,41-)"
done
elif [[ $line =~ $regex2 ]] ; then
echo "No matching commit"
exit 1
else
echo "commit $(echo $line | cut -c1-12,41-)"
fi
exit 0
$
so that using "$ format_commit.sh 1234" looks
at _all_ the commit references by using git rev-list
then greps that output for the matches, but it is
darn slow...
$ time ./format_commit.sh 1234
checking commits 1234...
commit 1234351cba95 ("xfs: introduce xlog_copy_iovec")
commit 1234471e2d11 ("perf header: Fix numa topology printing")
commit 1234f4bada54 ("hwrng: Kconfig: remove dependency for atmel-rng driver")
commit 12340313cf94 ("MAINTAINERS: add new cgroup list to CC notice")
commit 12346037a718 ("UBIFS: dump more in the lprops debugging check")
commit 12342c475f5d ("iwlwifi: proper monitor support")
commit 1234010684bb ("Add notation that the Asus W5F laptop has a short cable instead of 80-wire.")
commit 123411f2d0da ("[CPUFREQ] dprintf format fixes in cpufreq/speedstep-centrino.c")
real 0m24.535s
user 0m21.668s
sys 0m5.332s
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