In 6ce9d558ced (midx-write: skip rewriting MIDX with `--stdin-packs` unless needed, 2025-12-10), the MIDX machinery learned how to optimize out unnecessary writes with "--stdin-packs". In order to do this, it compares the contents of the in-progress write against a MIDX loaded directly from the object store. We load a separate MIDX (as opposed to checking our update relative to "ctx.m") because the MIDX code does not reuse an existing MIDX with --stdin-packs, and always leaves "ctx.m" as NULL. See commit 0c5a62f14bc (midx-write.c: do not read existing MIDX with `packs_to_include`, 2024-06-11) for details on why. If "ctx.m" is non-NULL, however, it is guaranteed to be checksum-valid, since we only assign "ctx.m" when "midx_checksum_valid()" returns true. Since the same guard does not exist for the MIDX we pass to "midx_needs_update()", we may ignore on-disk corruption when determining whether or not we can optimize out the write. Add a similar guard within "midx_needs_update()" to prevent such an issue. A more robust fix would involve revising 0c5a62f14bc and teaching the MIDX generation code how to reuse an existing MIDX even when invoked with "--stdin-packs", such that we could avoid side-loading the MIDX directly from the object store in order to call "midx_needs_update()". For now, pursue the minimal fix. Signed-off-by: Taylor Blau <me@ttaylorr.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.adoc to get started, then see
Documentation/giteveryday.adoc for a useful minimum set of commands, and
Documentation/git-<commandname>.adoc 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.adoc
(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 and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://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