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Remembering renames on the upstream side of history in an early merge of a rebase or cherry-pick for re-use in a latter merge of the same operation makes pretty good intuitive sense. However, trying to show that it doesn't cause some subtle behavioral difference or some funny edge or corner case is much more involved. And, in fact, it does introduce a subtle behavioral change. Document all the assumptions, special cases, and logic involved in such an optimization, and describe why this optimization is safe under the current optimizations/features/etc. -- even when the subtle behavioral change is triggered. Part of the point of adding this document that goes over the optimization in such laborious detail, is that it is possible that significant future changes (optimizations or feature changes) could interact with this optimization in interesting ways; this document is here to help folks making big changes sanity check that the assumptions and arguments underlying this optimization are still valid. (As a side note, creating this document forced me to review things in sufficient detail that I found I was not properly caching directory-rename-induced renames, resulting in the code not being aware of those renames and causing unnecessary diffcore_rename_extended() calls in subsequent merges.) A subsequent commit will add several testcases based on this document meant to stress-test the implementation and also document the case with the subtle behavioral change. Signed-off-by: Elijah Newren <newren@gmail.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.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