Qin ShiCheng
eb17aae2f8
repack works out which packs are redundant by looking for ".keep" files when it starts, then runs pack-objects, which looks for them all over again when it opens the packs. Two scans of the same directory, seconds apart, with nothing holding them together. A ".keep" that turns up in between loses objects. The parent did not see it, so the pack is on its list to delete. The child does see it, so it leaves that pack to itself: its objects are not copied into the new pack, not loosened for "-A", not kept for "-k" or "--cruft". The parent deletes the pack regardless, as repack_remove_redundant_pack() passes force_delete, which skips the ".keep" check in unlink_pack_path(). The objects are gone and repack exits successfully. The gap is easy to land in. index-pack names a pack after its contents and writes its ".keep" before it renames the packfile into place, so a "git fetch", or a push being migrated out of its quarantine, that brings in a pack identical to one we already have puts a ".keep" next to that pack. Checking for the ".keep" once more right before deleting would not help: a push holds it for a fraction of a second, and it may well be gone again by the time pack-objects has finished. When we may delete packs, that is with "-d" and either "-a", "-A", "--cruft" or "--geometric", write the names of the packs we may delete, the non-kept and cruft packs, to a file next to the refs snapshot we already write for "git multi-pack-index write", and pass it to every pack-objects we spawn with "--ignore-pack-keep-from". pack-objects then never treats those packs as kept, whatever appears on the disk. Every other pack, whether kept when we started or showing up later, still goes by its ".keep" file, so "--honor-pack-keep" stays. Otherwise nothing gets deleted and nothing is passed. The file has one name per line. A name with a newline in it gets split there, which at worst makes some other pack not count as kept: its objects may be copied, but none are lost. Unreachable objects of such a pack are still dropped by "-a -d", or by "--cruft-expiration" and "--unpack-unreachable" once they are old enough, as these drop unreachable objects by design, and a pack written again under the same name does not make them any younger; what changes is that the objects that are to be kept no longer go with them. The tests have a ".keep" appear on the pack about to be deleted as pack-objects starts, through a "git" wrapper found via "--exec-path", for "-a", "-A", "-k", "--cruft" with and without an expiration, "--pack-kept-objects", "--filter" and "--geometric". Signed-off-by: Qin ShiCheng <qeesung@live.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