pull: avoid segfault when commit lookup fails get_can_ff() and already_up_to_date() pass the result of lookup_commit_reference() straight to commit_list_insert() and repo_is_descendant_of() without checking it. When the object behind HEAD or one of the merge heads cannot be parsed, e.g. because a loose object was left truncated by a fetch or gc racing on the same repository, lookup_commit_reference() returns NULL and "git pull" segfaults instead of reporting the corruption. Treat a failed lookup as "cannot fast-forward" and "not up to date", so that the caller falls through to the normal merge path, which already diagnoses the broken object and fails cleanly. An alternative would be to report the breakage at each lookup site, which could give a more precise diagnosis. The minimal guards are preferred because they do no more than is needed to avoid the crash, and will be easy to drop once "git pull" is reworked to resolve object names into commit objects early and pass those around, at which point there will not be multiple lookups of the same object name to guard in the first place. The test corrupts the loose object in place rather than removing it: a missing object that is still recorded in the commit-graph is caught by the consistency check in fetch-pack before "git pull" reaches the fast-forward check, so removing it would not exercise the crash. Signed-off-by: Jiri Kuncar <jiri.kuncar@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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):