2c8ee1f53c
When writing a bundle to a file, the bundle code actually creates "your.bundle.lock" using our lockfile interface. We feed that output descriptor to a child git-pack-objects via run-command, which has the quirk that it closes the output descriptor in the parent. To avoid confusing the lockfile code (which still thinks the descriptor is valid), we dup() it, and operate on the duplicate. However, this has a confusing side effect: after the dup() but before we call pack-objects, we have _two_ descriptors open to the lockfile. If we call die() during that time, the lockfile code will try to clean up the partially-written file. It knows to close() the file before unlinking, since on some platforms (i.e., Windows) the open file would block the deletion. But it doesn't know about the duplicate descriptor. On Windows, triggering an error at the right part of the code will result in the cleanup failing and the lockfile being left in the filesystem. We can solve this by moving the dup() much closer to start_command(), shrinking the window in which we have the second descriptor open. It's easy to place this in such a way that no die() is possible. We could still die due to a signal in the exact wrong moment, but we already tolerate races there (e.g., a signal could come before we manage to put the file on the cleanup list in the first place). As a bonus, this shields create_bundle() itself from the duplicate-fd trick, and we can simplify its error handling (note that the lock rollback now happens unconditionally, but that's OK; it's a noop if we didn't open the lock in the first place). The included test uses an empty bundle to cause a failure at the right spot in the code, because that's easy to trigger (the other likely errors are write() problems like ENOSPC). Note that it would already pass on non-Windows systems (because they are happy to unlink an already-open file). Based-on-a-patch-by: Gaël Lhez <gael.lhez@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Tested-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-.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