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In a superproject some commands need to interact with submodules. They need to query values from the .gitmodules file either from the worktree of from certain revisions. At the moment this is quite hard since a caller would need to read the .gitmodules file from the history and then parse the values. We want to provide an API for this so we have one place to get values from .gitmodules from any revision (including the worktree). The API is realized as a cache which allows us to lazily read .gitmodules configurations by commit into a runtime cache which can then be used to easily lookup values from it. Currently only the values for path or name are stored but it can be extended for any value needed. It is expected that .gitmodules files do not change often between commits. Thats why we lookup the .gitmodules sha1 from a commit and then either lookup an already parsed configuration or parse and cache an unknown one for each sha1. The cache is lazily build on demand for each requested commit. This cache can be used for all purposes which need knowledge about submodule configurations. Example use cases are: * Recursive submodule checkout needs to lookup a submodule name from its path when a submodule first appears. This needs be done before this configuration exists in the worktree. * The implementation of submodule support for 'git archive' needs to lookup the submodule name to generate the archive when given a revision that is not checked out. * 'git fetch' when given the --recurse-submodules=on-demand option (or configuration) needs to lookup submodule names by path from the database rather than reading from the worktree. For new submodule it needs to lookup the name from its path to allow cloning new submodules into the .git folder so they can be checked out without any network interaction when the user does a checkout of that revision. Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net> Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Git - the stupid content tracker
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"git" can mean anything, 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
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.
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).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
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 http://news.gmane.org/gmane.comp.version-control.git/,
http://marc.info/?l=git and other archival sites.
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.