Git with broken hash generation to generate collisions between object IDs. Don't use this! https://undefinedbehavior.de/posts/commit-vandalism/
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Jeff King cd37996795 pack-objects: break out of want_object loop early
When pack-objects collects the list of objects to pack
(either from stdin, or via its internal rev-list), it
filters each one through want_object_in_pack().

This function loops through each existing packfile, looking
for the object. When we find it, we mark the pack/offset
combo for later use. However, we can't just return "yes, we
want it" at that point. If --honor-pack-keep is in effect,
we must keep looking to find it in _all_ packs, to make sure
none of them has a .keep. Likewise, if --local is in effect,
we must make sure it is not present in any non-local pack.

As a result, the sum effort of these calls is effectively
O(nr_objects * nr_packs). In an ordinary repository, we have
only a handful of packs, and this doesn't make a big
difference. But in pathological cases, it can slow the
counting phase to a crawl.

This patch notices the case that we have neither "--local"
nor "--honor-pack-keep" in effect and breaks out of the loop
early, after finding the first instance. Note that our worst
case is still "objects * packs" (i.e., we might find each
object in the last pack we look in), but in practice we will
often break out early. On an "average" repo, my git.git with
8 packs, this shows a modest 2% (a few dozen milliseconds)
improvement in the counting-objects phase of "git
pack-objects --all <foo" (hackily instrumented by sticking
exit(0) right after list_objects).

But in a much more pathological case, it makes a bigger
difference. I ran the same command on a real-world example
with ~9 million objects across 1300 packs. The counting time
dropped from 413s to 45s, an improvement of about 89%.

Note that this patch won't do anything by itself for a
normal "git gc", as it uses both --honor-pack-keep and
--local.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-29 11:05:07 -07:00
block-sha1
builtin pack-objects: break out of want_object loop early 2016-07-29 11:05:07 -07:00
ci
compat Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
contrib Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
Documentation Sixth batch of topics for 2.10 2016-07-19 13:26:16 -07:00
ewah
git-gui
gitk-git
gitweb
mergetools
perl git-svn: warn instead of dying when commit data is missing 2016-07-09 22:53:54 +00:00
po Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
ppc
refs coccinelle: apply object_id Coccinelle transformations 2016-06-28 11:39:02 -07:00
t t/perf: add tests for many-pack scenarios 2016-07-29 11:05:06 -07:00
templates
vcs-svn
xdiff Merge branch 'rs/xdiff-hunk-with-func-line' into maint 2016-06-27 09:56:24 -07:00
.gitattributes .gitattributes: set file type for C files 2016-07-07 14:11:15 -07:00
.gitignore
.mailmap mailmap: use main email address for dturner 2016-07-06 10:57:01 -07:00
.travis.yml perf: accommodate for MacOSX 2016-06-21 11:18:17 -07:00
abspath.c
aclocal.m4
advice.c i18n: advice: internationalize message for conflicts 2016-06-17 15:45:48 -07:00
advice.h
alias.c
alloc.c
archive-tar.c archive-tar: huge offset and future timestamps would not work on 32-bit 2016-07-15 10:51:55 -07:00
archive-zip.c
archive.c pathspec: rename free_pathspec() to clear_pathspec() 2016-06-02 14:09:22 -07:00
archive.h
argv-array.c
argv-array.h
attr.c
attr.h
base85.c
bisect.c Merge branch 'jk/printf-format' 2016-07-19 13:22:22 -07:00
bisect.h
blob.c
blob.h
branch.c
branch.h
builtin.h
bulk-checkin.c
bulk-checkin.h
bundle.c
bundle.h
cache-tree.c
cache-tree.h
cache.h find_pack_entry: replace last_found_pack with MRU cache 2016-07-29 11:05:07 -07:00
check_bindir
check-builtins.sh
check-racy.c
color.c Merge branch 'jk/ansi-color' 2016-07-11 10:31:05 -07:00
color.h Merge branch 'js/color-on-windows-comment' 2016-07-11 10:31:09 -07:00
column.c
column.h column: support piping stdout to external git-column process 2012-04-27 09:26:38 -07:00
combine-diff.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
command-list.txt
commit-slab.h
commit.c Merge branch 'jk/printf-format' 2016-07-19 13:22:22 -07:00
commit.h Merge branch 'jk/printf-format' 2016-07-19 13:22:22 -07:00
common-main.c mingw: declare main()'s argv as const 2016-07-06 08:11:47 -07:00
config.c Merge branch 'jk/upload-pack-hook' 2016-07-06 13:38:11 -07:00
config.mak.in
config.mak.uname mingw: make isatty() recognize MSYS2's pseudo terminals (/dev/pty*) 2016-05-26 13:12:02 -07:00
configure.ac
connect.c connect: read $GIT_SSH_COMMAND from config file 2016-07-06 14:04:09 -07:00
connect.h
connected.c
connected.h
convert.c
convert.h
copy.c
COPYING
credential-cache--daemon.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
credential-cache.c add an extra level of indirection to main() 2016-07-01 15:09:10 -07:00
credential-store.c add an extra level of indirection to main() 2016-07-01 15:09:10 -07:00
credential.c
credential.h
csum-file.c
csum-file.h
ctype.c
daemon.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
date.c local_tzoffset: detect errors from tm_to_time_t 2016-06-20 15:08:07 -07:00
decorate.c Remove get_object_hash. 2015-11-20 08:02:05 -05:00
decorate.h
delta.h
diff-delta.c
diff-lib.c
diff-no-index.c
diff.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
diff.h
diffcore-break.c diff: rename struct diff_filespec's sha1_valid member 2016-06-28 11:39:02 -07:00
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c diffcore-pickaxe: support case insensitive match on non-ascii 2016-07-01 12:44:57 -07:00
diffcore-rename.c diff: rename struct diff_filespec's sha1_valid member 2016-06-28 11:39:02 -07:00
diffcore.h diff: rename struct diff_filespec's sha1_valid member 2016-06-28 11:39:02 -07:00
dir.c
dir.h
editor.c
entry.c
environment.c Merge branch 'js/windows-dotgit' into maint 2016-05-26 13:17:23 -07:00
exec_cmd.c
exec_cmd.h
fast-import.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
fetch-pack.c
fetch-pack.h
fmt-merge-msg.h
fsck.c
fsck.h
generate-cmdlist.sh
gettext.c gettext: add is_utf8_locale() 2016-07-01 12:44:57 -07:00
gettext.h gettext: add is_utf8_locale() 2016-07-01 12:44:57 -07:00
git-add--interactive.perl add--interactive: respect diff.compactionHeuristic 2016-06-16 11:38:58 -07:00
git-archimport.perl
git-bisect.sh i18n: unmark die messages for translation 2016-06-17 15:46:10 -07:00
git-compat-util.h Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
git-cvsexportcommit.perl
git-cvsimport.perl
git-cvsserver.perl
git-difftool--helper.sh
git-difftool.perl
git-filter-branch.sh
git-instaweb.sh
git-merge-octopus.sh i18n: git-sh-setup.sh: mark strings for translation 2016-06-17 15:45:48 -07:00
git-merge-one-file.sh
git-merge-resolve.sh
git-mergetool--lib.sh
git-mergetool.sh
git-p4.py Merge branch 'ls/p4-tmp-refs' 2016-07-19 13:22:24 -07:00
git-parse-remote.sh
git-quiltimport.sh
git-rebase--am.sh rebase: update comment about FreeBSD /bin/sh 2016-06-17 11:04:38 -07:00
git-rebase--interactive.sh Merge branch 'ps/rebase-i-auto-unstash-upon-abort' 2016-07-13 11:24:17 -07:00
git-rebase--merge.sh Merge branch 'em/newer-freebsd-shells-are-fine-with-returns' into maint 2016-07-06 13:06:41 -07:00
git-rebase.sh i18n: git-sh-setup.sh: mark strings for translation 2016-06-17 15:45:48 -07:00
git-relink.perl
git-remote-testgit.sh
git-request-pull.sh
git-send-email.perl Merge branch 'jc/send-email-skip-backup' 2016-07-11 10:31:04 -07:00
git-sh-i18n.sh i18n: rebase-interactive: mark here-doc strings for translation 2016-06-17 15:45:48 -07:00
git-sh-setup.sh Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
git-stash.sh i18n: git-sh-setup.sh: mark strings for translation 2016-06-17 15:45:48 -07:00
git-submodule.sh Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
git-svn.perl git-svn: clone: Fail on missing url argument 2016-07-03 06:04:47 +00:00
GIT-VERSION-GEN Git 2.9.2 2016-07-15 10:48:16 -07:00
git-web--browse.sh
git.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
git.rc
gpg-interface.c gpg-interface: check gpg signature creation status 2016-06-17 17:03:57 -07:00
gpg-interface.h
graph.c Merge branch 'js/log-to-diffopt-file' 2016-07-19 13:22:15 -07:00
graph.h pretty: pass graph width to pretty formatting for use in '%>|(N)' 2016-06-16 11:43:36 -07:00
grep.c Merge branch 'nd/icase' 2016-07-19 13:22:17 -07:00
grep.h grep/pcre: prepare locale-dependent tables for icase matching 2016-07-01 12:44:57 -07:00
hashmap.c
hashmap.h
help.c t0006: skip "far in the future" test when unsigned long is not long enough 2016-07-15 09:05:53 -07:00
help.h
hex.c hex: add oid_to_hex_r() 2016-06-28 11:39:02 -07:00
http-backend.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
http-fetch.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
http-push.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
http-walker.c
http.c Merge branch 'ep/http-curl-trace' 2016-07-06 13:38:06 -07:00
http.h Merge branch 'ep/http-curl-trace' 2016-07-06 13:38:06 -07:00
ident.c
imap-send.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
INSTALL
khash.h
kwset.c
kwset.h
levenshtein.c
levenshtein.h
LGPL-2.1
line-log.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
line-log.h
line-range.c
line-range.h
list-objects.c
list-objects.h
ll-merge.c
ll-merge.h
lockfile.c
lockfile.h
log-tree.c Merge branch 'js/log-to-diffopt-file' 2016-07-19 13:22:15 -07:00
log-tree.h
mailinfo.c
mailinfo.h
mailmap.c
mailmap.h
Makefile add generic most-recently-used list 2016-07-29 11:05:07 -07:00
match-trees.c
merge-blobs.c
merge-blobs.h
merge-recursive.c merge-recursive: convert merge_recursive_generic() to object_id 2016-06-28 11:39:02 -07:00
merge-recursive.h merge-recursive: convert merge_recursive_generic() to object_id 2016-06-28 11:39:02 -07:00
merge.c
mergesort.c
mergesort.h
mru.c add generic most-recently-used list 2016-07-29 11:05:07 -07:00
mru.h add generic most-recently-used list 2016-07-29 11:05:07 -07:00
name-hash.c
notes-cache.c
notes-cache.h
notes-merge.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
notes-merge.h
notes-utils.c
notes-utils.h
notes.c use string_list initializer consistently 2016-06-13 10:37:51 -07:00
notes.h
object.c
object.h
pack-bitmap-write.c
pack-bitmap.c
pack-bitmap.h
pack-check.c
pack-objects.c
pack-objects.h
pack-revindex.c
pack-revindex.h
pack-write.c sha1_file: drop free_pack_by_name 2016-07-29 11:05:06 -07:00
pack.h
pager.c
parse-options-cb.c Merge branch 'jk/parseopt-string-list' into jk/string-list-static-init 2016-06-13 10:37:48 -07:00
parse-options.c
parse-options.h
patch-delta.c
patch-ids.c
patch-ids.h
path.c Merge branch 'lp/typofixes' into maint 2016-05-26 13:17:21 -07:00
pathspec.c pathspec: rename free_pathspec() to clear_pathspec() 2016-06-02 14:09:22 -07:00
pathspec.h pathspec: rename free_pathspec() to clear_pathspec() 2016-06-02 14:09:22 -07:00
pkt-line.c
pkt-line.h
preload-index.c
pretty.c Merge branch 'nd/graph-width-padded' into maint 2016-07-11 10:44:09 -07:00
prio-queue.c
prio-queue.h
progress.c
progress.h
prompt.c
prompt.h
quote.c Merge branch 'nd/icase' 2016-07-19 13:22:17 -07:00
quote.h Merge branch 'nd/icase' 2016-07-19 13:22:17 -07:00
reachable.c
reachable.h
read-cache.c add: add --chmod=+x / --chmod=-x options 2016-06-07 17:43:39 -07:00
README.md README.md: format CLI commands with code syntax 2016-05-31 08:54:24 -07:00
ref-filter.c
ref-filter.h
reflog-walk.c reflog: continue walking the reflog past root commits 2016-06-06 15:06:44 -07:00
reflog-walk.h
refs.c
refs.h refs.h: fix misspelt "occurred" in a comment 2016-06-10 14:53:32 -07:00
RelNotes Git 2.9.2 2016-07-15 10:48:16 -07:00
remote-curl.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
remote-testsvn.c common-main: call git_extract_argv0_path() 2016-07-01 15:09:10 -07:00
remote.c Merge branch 'nd/remote-plural-ours-plus-theirs' into maint 2016-05-26 13:17:18 -07:00
remote.h
replace_object.c
rerere.c Merge branch 'jc/rerere-multi' 2016-05-23 14:54:38 -07:00
rerere.h
resolve-undo.c
resolve-undo.h
revision.c Merge branch 'mj/log-show-signature-conf' 2016-07-11 10:31:08 -07:00
revision.h
run-command.c run-command: add pipe_command helper 2016-06-17 17:03:56 -07:00
run-command.h run-command: add pipe_command helper 2016-06-17 17:03:56 -07:00
send-pack.c send-pack: use buffered I/O to talk to pack-objects 2016-06-08 16:02:40 -07:00
send-pack.h
sequencer.c Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
sequencer.h
server-info.c
setup.c i18n: setup: mark strings for translation 2016-06-17 15:45:48 -07:00
sh-i18n--envsubst.c add an extra level of indirection to main() 2016-07-01 15:09:10 -07:00
sha1_file.c find_pack_entry: replace last_found_pack with MRU cache 2016-07-29 11:05:07 -07:00
sha1_name.c
sha1-array.c
sha1-array.h sha1-array.c: mark a private file-scope symbol as static 2012-09-15 22:58:21 -07:00
sha1-lookup.c
sha1-lookup.h
shallow.c
shell.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
shortlog.h shortlog: support outputting to streams other than stdout 2016-06-24 14:25:49 -07:00
show-index.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
sideband.c Merge branch 'lf/recv-sideband-cleanup' 2016-07-19 13:22:14 -07:00
sideband.h sideband.c: make send_sideband() return void 2016-06-16 11:40:19 -07:00
sigchain.c
sigchain.h
split-index.c
split-index.h
strbuf.c
strbuf.h Merge branch 'pb/strbuf-read-file-doc' into maint 2016-07-06 13:06:45 -07:00
streaming.c
streaming.h
string-list.c
string-list.h
submodule-config.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
submodule-config.h submodule-config: keep shallow recommendation around 2016-05-27 10:40:45 -07:00
submodule.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
submodule.h
symlinks.c
tag.c
tag.h
tar.h
tempfile.c
tempfile.h
thread-utils.c
thread-utils.h
trace.c
trace.h
trailer.c
trailer.h
transport-helper.c i18n: transport-helper.c: change N_() call to _() 2016-06-17 15:45:49 -07:00
transport.c i18n: transport: mark strings for translation 2016-06-17 15:45:48 -07:00
transport.h
tree-diff.c Merge branch 'jk/avoid-unbounded-alloca' into maint 2016-07-06 13:06:39 -07:00
tree-walk.c
tree-walk.h
tree.c
tree.h
unicode_width.h
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c unpack-trees: fix English grammar in do-this-before-that messages 2016-06-27 08:29:36 -07:00
unpack-trees.h
update_unicode.sh
upload-pack.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
url.c
url.h
urlmatch.c
urlmatch.h
usage.c
userdiff.c userdiff: add built-in pattern for CSS 2016-06-03 14:45:56 -07:00
userdiff.h
utf8.c
utf8.h
varint.c
varint.h
version.c
version.h
versioncmp.c
walker.c walker: let walker_say take arbitrary formats 2016-07-08 10:11:23 -07:00
walker.h walker: let walker_say take arbitrary formats 2016-07-08 10:11:23 -07:00
wildmatch.c
wildmatch.h
worktree.c Merge branch 'nd/worktree-cleanup-post-head-protection' 2016-07-06 13:38:11 -07:00
worktree.h
wrap-for-bin.sh
wrapper.c Merge branch 'jk/write-file' 2016-07-19 13:22:23 -07:00
write_or_die.c write_or_die: remove the unused write_or_whine() function 2016-06-10 10:54:27 -07:00
ws.c
wt-status.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
wt-status.h
xdiff-interface.c xdiff: don't trim common tail with -W 2016-05-31 13:08:56 -07:00
xdiff-interface.h
zlib.c

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 http://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-.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 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.

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