In66ae9a57b8(t3404: rebase -i: demonstrate short SHA-1 collision, 2013-08-23), we added a test case that demonstrated how it is possible that a previously unambiguous short commit ID could become ambiguous *during* a rebase. In75c6976655(rebase -i: fix short SHA-1 collision, 2013-08-23), we fixed that problem simply by writing out the todo list with expanded commit IDs (except *right* before letting the user edit the todo list, in which case we shorten them, but we expand them right after the file was edited). However, the bug resurfaced as a side effect of393adf7a6f(sequencer: directly call pick_commits() from complete_action(), 2019-11-24): as of this commit, the sequencer no longer re-reads the todo list after writing it out with expanded commit IDs. The only redeeming factor is that the todo list is already parsed at that stage, including all the commits corresponding to the commands, therefore the sequencer can continue even if the internal todo list has short commit IDs. That does not prevent problems, though: the sequencer writes out the `done` and `git-rebase-todo` files incrementally (i.e. overwriting the todo list with a version that has _short_ commit IDs), and if a merge conflict happens, or if an `edit` or a `break` command is encountered, a subsequent `git rebase --continue` _will_ re-read the todo list, opening an opportunity for the "short SHA-1 collision" bug again. To avoid that, let's make sure that we do expand the commit IDs in the todo list as soon as we have parsed it after letting the user edit it. Additionally, we improve the 'short SHA-1 collide' test case in t3404 to test specifically for the case where the rebase is resumed. We also hard-code the expected colliding short SHA-1s, to document the expectation (and to make it easier on future readers). Note that we specifically test that the short commit ID is used in the `git-rebase-todo.tmp` file: this file is created by the fake editor in the test script and reflects the state that would have been presented to the user to edit. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.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).
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://lore.kernel.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