ODB transactions support being nested. Only the outermost
{begin,end}_odb_transaction() start and finish a transaction. This
allows internal object write codepaths to be optimized with ODB
transactions without worrying about whether a transaction is already
active. When {begin,end}_odb_transaction() is invoked during an active
transaction, these operations are essentially treated as no-ops. This
can make the interface a bit awkward to use, as calling
end_odb_transaction() does not guarantee that a transaction is actually
ended. Thus, in situations where a transaction needs to be explicitly
flushed, flush_odb_transaction() must be used.
To remove the need for an explicit transaction flush operation via
flush_odb_transaction() and better clarify transaction semantics, drop
the transaction nesting mechanism in favor of begin_odb_transaction()
returning a NULL transaction value to signal it was a no-op, and
end_odb_transaction() behaving as a no-op when a NULL transaction value
is passed. This is safe for existing callers as the transaction value
wired to end_odb_transaction() already comes from
begin_odb_transaction() and thus continues the same no-op behavior when
a transaction is already pending. With this model, passing a pending
transaction to end_odb_transaction() ensures it is committed at that
point in time.
Signed-off-by: Justin Tobler <jltobler@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.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