Re: [RFC PATCH] GIT-VERSION-GEN: set --abbrev=9 to match auto-scaling
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Dec 6, 2016, 18:17 UTC
- Message-ID
- <xmqqwpfc2a7g.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <20161206140259.lly76xkvsj7su3om@sigill.intra.peff.net>
Jeff King <peff@peff.net> writes:
Show 29 quoted lines
> On Mon, Dec 05, 2016 at 10:01:19AM -0800, Junio C Hamano wrote: > >> > That said, I think the right patch may be to just drop --abbrev >> > entirely. >> > ... >> > I think at that point it was a noop, as 7 should have been the default. >> > And now we probably ought to drop it, so that we can use the >> > auto-scaling default. >> >> Yeah, I agree. >> >> It does mean that snapshot binaries built out of the same commit in >> the same repository before and after a repack have higher chances of >> getting named differently, which may surprise people, but that >> already is possible with a fixed length if the repacking involves >> pruning (albeit with lower probabilities), and I do not think it is >> a problem. > > I think that the number is already unstable, even with --abbrev, as it > just specifies a minimum. So any operation that creates objects has a > possibility of increasing the length. Or more likely, two people > describing the same version may end up with different strings because > they have different objects in their repositories (e.g., I used to > carry's trast's git-notes archive of the mailing list which added quite > a few objects). > > I agree that having it change over the course of a repack is slightly > _more_ surprising than those cases, but ultimately the value just isn't > stable.
Yup, that is what I meant to say with "that is already possible" and we are on the same page. As all three of us seem to be happy with just dropping --abbrev and letting describe do its default thing (as configured by whoever is doing the build), let's do so.
-- >8 -- From: Ramsay Jones <ramsay@ramsayjones.plus.com> Date: Sun, 4 Dec 2016 20:45:59 +0000 Subject: [PATCH] GIT-VERSION-GEN: do not force abbreviation length used by 'describe'
The default version name for a Git binary is computed by running "git describe" on the commit the binary is made out of, basing on a tag whose name matches "v[0-9]*", e.g. v2.11.0-rc2-2-g7f1dc9.
In the very early days, with 9b88fcef7d ("Makefile: use git-describe to mark the git version.", 2005-12-27), we used "--abbrev=4" to get absolute minimum number of abbreviated commit object name. This was later changed to match the default minimum of 7 with bf505158d0 ("Git 1.7.10.1", 2012-05-01).
These days, the "default minimum" scales automatically depending on the size of the repository, and there is no point in specifying a particular abbreviation length; all we wanted since Git 1.7.10.1 days was to get "something reasonable we would use by default".
Just drop "--abbrev=<number>" from the invocation of "git describe" and let the command pick what it thinks is appropriate, taking the end user's configuration and the repository contents into account.
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Helped-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> --- GIT-VERSION-GEN | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN index 556fbfc104..f95b04bb36 100755 --- a/GIT-VERSION-GEN +++ b/GIT-VERSION-GEN @@ -12,7 +12,7 @@ if test -f version then VN=$(cat version) || VN="$DEF_VER" elif test -d ${GIT_DIR:-.git} -o -f .git && - VN=$(git describe --match "v[0-9]*" --abbrev=7 HEAD 2>/dev/null) && + VN=$(git describe --match "v[0-9]*" HEAD 2>/dev/null) && case "$VN" in *$LF*) (exit 1) ;; v[0-9]*)
-- 2.11.0-263-gd89495280e