The options --exit-code and --quiet instruct git diff to indicate whether it found any significant changes by exiting with code 1 if it did and 0 if there were none. Currently this doesn't work if external diff programs are involved, as we have no way to learn what they found. Add that ability in the form of the new configuration options diff.trustExitCode and diff.<driver>.trustExitCode and the environment variable GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE. They pair with the config options diff.external and diff.<driver>.command and the environment variable GIT_EXTERNAL_DIFF, respectively. The new options are off by default, keeping the old behavior. Enabling them indicates that the external diff returns exit code 1 if it finds significant changes and 0 if it doesn't, like diff(1). The name of the new options is taken from the git difftool and mergetool options of similar purpose. (There they enable passing on the exit code of a diff tool and to infer whether a merge done by a merge tool is successful.) The new feature sets the diff flag diff_from_contents in diff_setup_done() if we need the exit code and are allowed to call external diffs. This disables the optimization that avoids calling the program with --quiet. Add it back by skipping the call if the external diff is not able to report empty diffs. We can only do that check after evaluating the file-specific attributes in run_external_diff(). If we do run the external diff with --quiet, send its output to /dev/null. I considered checking the output of the external diff to check whether its empty. It was added as 11be65cfa4 (diff: fix --exit-code with external diff, 2024-05-05) and quickly reverted, as it does not work with external diffs that do not write to stdout. There's no reason why a graphical diff tool would even need to write anything there at all. I also considered using a non-zero exit code for empty diffs, which could be done without adding new configuration options. We'd need to disable the optimization that allows git diff --quiet to skip calling external diffs, though -- that might be quite surprising if graphical diff programs are involved. And assigning the opposite meaning of the exit codes compared to diff(1) and git diff --exit-code to the external diff can cause unnecessary confusion. Suggested-by: Phillip Wood <phillip.wood123@gmail.com> Signed-off-by: René Scharfe <l.s.r@web.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 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