When cloning a repo with a --filter and with --recurse-submodules
enabled, the partial clone filter only applies to the top-level repo.
This can lead to unexpected bandwidth and disk usage for projects which
include large submodules. For example, a user might wish to make a
partial clone of Gerrit and would run:
`git clone --recurse-submodules --filter=blob:5k https://gerrit.googlesource.com/gerrit`.
However, only the superproject would be a partial clone; all the
submodules would have all blobs downloaded regardless of their size.
With this change, the same filter can also be applied to submodules,
meaning the expected bandwidth and disk savings apply consistently.
To avoid changing default behavior, add a new clone flag,
`--also-filter-submodules`. When this is set along with `--filter` and
`--recurse-submodules`, the filter spec is passed along to git-submodule
and git-submodule--helper, such that submodule clones also have the
filter applied.
This applies the same filter to the superproject and all submodules.
Users who need to customize the filter per-submodule would need to clone
with `--no-recurse-submodules` and then manually initialize each
submodule with the proper filter.
Applying filters to submodules should be safe thanks to Jonathan Tan's
recent work [1, 2, 3] eliminating the use of alternates as a method of
accessing submodule objects, so any submodule object access now triggers
a lazy fetch from the submodule's promisor remote if the accessed object
is missing. This patch is a reworked version of [4], which was created
prior to Jonathan Tan's work.
[1]: 8721e2e (Merge branch 'jt/partial-clone-submodule-1', 2021-07-16)
[2]: 11e5d0a (Merge branch 'jt/grep-wo-submodule-odb-as-alternate',
2021-09-20)
[3]: 162a13b (Merge branch 'jt/no-abuse-alternate-odb-for-submodules',
2021-10-25)
[4]: https://lore.kernel.org/git/52bf9d45b8e2b72ff32aa773f2415bf7b2b86da2.1563322192.git.steadmon@google.com/
Signed-off-by: Josh Steadmon <steadmon@google.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).
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
