From: Shawn O. Pearce <spearce@spearce.org>
Date: Sun, 24 Feb 2008 08:07:31 +0000 (-0500)
Subject: Teach git-describe --exact-match to avoid expensive tag searches
X-Git-Tag: v1.5.5-rc0~145^2~1
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/2c33f7575452f53382dcf77fdc88a2ea5d46f09d?ds=inline;hp=2c33f7575452f53382dcf77fdc88a2ea5d46f09d

Teach git-describe --exact-match to avoid expensive tag searches

Sometimes scripts want (or need) the annotated tag name that exactly
matches a specific commit, or no tag at all.  In such cases it can be
difficult to determine if the output of `git describe $commit` is a
real tag name or a tag+abbreviated commit.  A common idiom is to run
git-describe twice:

if test $(git describe $commit) = $(git describe --abbrev=0 $commit)
...

but this is a huge waste of time if the caller is just going to pick a
different method to describe $commit or abort because it is not exactly
an annotated tag.

Setting the maximum number of candidates to 0 allows the caller to ask
for only a tag that directly points at the supplied commit, or to have
git-describe abort if no such item exists.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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