When searching the commit graph for tag candidates, `git-describe`
will stop as soon as there is only one active branch left and
it already found an annotated tag as a candidate.
This works well as long as all branches eventually connect back
to a common root, but if the tags are found across branches
with no common ancestor
B
o----.
\
o-----o---o----x
A
it can happen that the search on one branch terminates prematurely
because a tag was found on another, independent branch. This scenario
isn't quite as obscure as it sounds, since cloning with a limited
depth often introduces many independent "dead ends" into the commit
graph.
The help text of `git-describe` states pretty clearly that when
describing a commit D, the number appended to the emitted tag X should
correspond to the number of commits found by `git log X..D`.
Thus, this commit modifies the stopping condition to only abort
the search when only one branch is left to search *and* all current
best candidates are descendants from that branch.
For repositories with a single root, this condition is always
true: When the search is reduced to a single active branch, the
current commit must be an ancestor of *all* tag candidates. This
means that in the common case, this change will have no negative
performance impact since the same number of commits as before will
be traversed.
Signed-off-by: Benno Evers <benno@bmevers.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public
License version 2 (some parts of it are under different licenses,
compatible with the GPLv2). It was originally written by Linus
Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/
including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
Issues which are security relevant should be disclosed privately to
the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that
list the current status of various development topics to the mailing
list. The discussion following them give a good reference for
project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very
first version. He described the tool as "the stupid content tracker"
and the name as (depending on your mood):
random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
"global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
"goddamn idiotic truckload of sh*t": when it breaks
