2dda741279
Under certain circumstances, gitCommitByP4Change() can enter an infinite
loop resulting in `git p4 sync` hanging forever.
The problem is that
`git rev-list --bisect <latest> ^<earliest>` can return `<latest>`,
which would result in reinspecting <latest> and potentially an infinite loop.
This can happen when importing just a subset of P4 repository
and/or with explicit "--changesfile" option.
A real-life example:
"""
looking in ref refs/remotes/p4/mybranch for change 26894 using bisect...
Reading pipe: git rev-parse refs/remotes/p4/mybranch
trying: earliest latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git cat-file commit 147f5d3292af2e1cc4a56a7b96db845144c68486
current change 25339
trying: earliest ^147f5d3292af2e1cc4a56a7b96db845144c68486 latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1 ^147f5d3292af2e1cc4a56a7b96db845144c68486
Reading pipe: git cat-file commit 51db83df9d588010d0bd995641c85aa0408a5bb9
current change 25420
trying: earliest ^51db83df9d588010d0bd995641c85aa0408a5bb9 latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1 ^51db83df9d588010d0bd995641c85aa0408a5bb9
Reading pipe: git cat-file commit e8f83909ceb570f5a7e48c2853f3c5d8207cea52
current change 25448
trying: earliest ^e8f83909ceb570f5a7e48c2853f3c5d8207cea52 latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1 ^e8f83909ceb570f5a7e48c2853f3c5d8207cea52
Reading pipe: git cat-file commit 09a48eb7acd594dce52e06681be9c366e1844d66
current change 25521
trying: earliest ^09a48eb7acd594dce52e06681be9c366e1844d66 latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1 ^09a48eb7acd594dce52e06681be9c366e1844d66
Reading pipe: git cat-file commit 4daff81c520a82678e1ef347f2b5e97258101ae1
current change 26907
trying: earliest ^09a48eb7acd594dce52e06681be9c366e1844d66 latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1 ^09a48eb7acd594dce52e06681be9c366e1844d66
Reading pipe: git cat-file commit 4daff81c520a82678e1ef347f2b5e97258101ae1
current change 26907
trying: earliest ^09a48eb7acd594dce52e06681be9c366e1844d66 latest 4daff81c520a82678e1ef347f2b5e97258101ae1
Reading pipe: git rev-list --bisect 4daff81c520a82678e1ef347f2b5e97258101ae1 ^09a48eb7acd594dce52e06681be9c366e1844d66
Reading pipe: git cat-file commit 4daff81c520a82678e1ef347f2b5e97258101ae1
current change 26907
...
"""
The fix is two-fold:
* detect an infinite loop and die right away
instead of looping forever;
* make sure, `git rev-list --bisect` can't return "latestCommit" again
by excluding it from the rev-list range explicitly.
Signed-off-by: Andrey Mazo <amazo@checkvideo.com>
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-.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).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission). To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.
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