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Elijah Newren c91c944a06 rebase: define linearization ordering and enforce it
Ever since commit 3f213981e4 ("add tests for rebasing merged history",
2013-06-06), t3425 has had tests which included the rebasing of merged
history and whose order of applied commits was checked.  Unfortunately,
the tests expected different behavior depending on which backend was in
use.  Implementing these checks was the following four lines (including
the TODO message) which were repeated verbatim three times in t3425:

    #TODO: make order consistent across all flavors of rebase
    test_run_rebase success 'e n o' ''
    test_run_rebase success 'e n o' -m
    test_run_rebase success 'n o e' -i

As part of the effort to reduce differences between the rebase backends
so that users get more uniform behavior, let's define the correct
behavior and modify the different backends so they all get the right
answer.  It turns out that the difference in behavior here is entirely
due to topological sorting; since some backends require topological
sorting (particularly when --rebase-merges is specified), require it for
all modes.  Modify the am and merge backends to implement this.

Performance Considerations:

I was unable to measure any appreciable performance difference with this
change.  Trying to control the run-to-run variation was difficult; I
eventually found a headless beefy box that I could ssh into, which
seemed to help.  Using git.git, I ran the following testcase:
    $ git reset --hard v2.20.0-rc1~2
    $ time git rebase --quiet v2.20.0-rc0~16

I first ran once to warm any disk caches, then ran five subsequent runs
and recorded the times of those five.  I observed the following results
for the average time:

     Before this change:
       "real" timing: 1.340s (standard deviation: 0.040s)
       "user" timing: 1.050s (standard deviation: 0.041s)
       "sys"  timing: 0.270s (standard deviation: 0.011s)
     After  this change:
       "real" timing: 1.327s (standard deviation: 0.065s)
       "user" timing: 1.031s (standard deviation: 0.061s)
       "sys"  timing: 0.280s (standard deviation: 0.014s)

Measurements aside, I would expect the timing for walking revisions to
be dwarfed by the work involved in creating and applying patches, so
this isn't too surprising.  Further, while somewhat counter-intuitive,
it is possible that turning on topological sorting is actually a
performance improvement: by way of comparison, turning on --topo-order
made fast-export faster (see
https://public-inbox.org/git/20090211135640.GA19600@coredump.intra.peff.net/).

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-12-28 12:49:48 -08:00
.github
Documentation Git 2.20.1 2018-12-15 12:31:34 +09:00
block-sha1
builtin git-rebase, sequencer: extend --quiet option for the interactive machinery 2018-12-28 12:49:48 -08:00
ci Merge branch 'ab/dynamic-gettext-poison' 2018-11-19 16:24:39 +09:00
compat Merge branch 'ss/msvc-strcasecmp' 2018-12-01 21:41:45 +09:00
contrib Merge branch 'jc/cocci-preincr' into maint 2018-11-21 22:58:08 +09:00
ewah
git-gui
gitk-git
gitweb
mergetools
negotiator
perl
po l10n: de.po: fix two messages 2018-12-07 19:43:07 +01:00
ppc
refs Merge branch 'nd/per-worktree-ref-iteration' 2018-11-26 23:13:43 +09:00
sha1collisiondetection@232357eb2e
sha1dc
t rebase: define linearization ordering and enforce it 2018-12-28 12:49:48 -08:00
templates
vcs-svn
xdiff
.clang-format
.editorconfig
.gitattributes Merge branch 'ds/hash-independent-tests-fix' into maint 2018-12-15 12:24:32 +09:00
.gitignore
.gitmodules
.mailmap Merge branch 'jn/mailmap-update' into maint 2018-11-21 22:57:47 +09:00
.travis.yml Merge branch 'ab/dynamic-gettext-poison' 2018-11-19 16:24:39 +09:00
.tsan-suppressions
COPYING
GIT-VERSION-GEN Git 2.20.1 2018-12-15 12:31:34 +09:00
INSTALL
LGPL-2.1
Makefile Merge branch 'js/mingw-o-append' into maint 2018-11-21 22:57:44 +09:00
README.md
RelNotes Git 2.20.1 2018-12-15 12:31:34 +09:00
abspath.c
aclocal.m4
advice.c
advice.h
alias.c
alias.h
alloc.c
alloc.h
apply.c Merge branch 'js/apply-recount-allow-noop' 2018-11-18 18:23:56 +09:00
apply.h
archive-tar.c Upcast size_t variables to uintmax_t when printing 2018-11-12 16:43:52 +09:00
archive-zip.c
archive.c
archive.h
argv-array.c
argv-array.h
attr.c attr.c: remove #ifdef NO_PTHREADS 2018-11-05 13:42:11 +09:00
attr.h
banned.h
base85.c
bisect.c
bisect.h
blame.c
blame.h
blob.c
blob.h
branch.c
branch.h
builtin.h
bulk-checkin.c
bulk-checkin.h
bundle.c Merge branch 'jk/close-duped-fd-before-unlock-for-bundle' 2018-11-18 18:23:59 +09:00
bundle.h
cache-tree.c
cache-tree.h
cache.h Merge branch 'bp/refresh-index-using-preload' 2018-11-13 22:37:26 +09:00
chdir-notify.c
chdir-notify.h
check-builtins.sh
check-racy.c
check_bindir
checkout.c
checkout.h
color.c
color.h
column.c
column.h
combine-diff.c Merge branch 'jk/xdiff-interface' 2018-11-13 22:37:27 +09:00
command-list.txt Merge branch 'du/cherry-is-plumbing' into maint 2018-11-21 22:58:05 +09:00
commit-graph.c Merge branch 'ds/commit-graph-with-grafts' into maint 2018-11-21 22:57:47 +09:00
commit-graph.h Merge branch 'ds/commit-graph-with-grafts' into maint 2018-11-21 22:57:47 +09:00
commit-reach.c
commit-reach.h Merge branch 'ds/add-missing-tags' 2018-11-13 22:37:24 +09:00
commit-slab-decl.h
commit-slab-impl.h
commit-slab.h
commit.c Merge branch 'ds/commit-graph-with-grafts' into maint 2018-11-21 22:57:47 +09:00
commit.h Merge branch 'js/shallow-and-fetch-prune' into maint 2018-11-21 22:57:51 +09:00
common-main.c
config.c index: make index.threads=true enable ieot and eoie 2018-11-21 16:46:54 +09:00
config.h index: make index.threads=true enable ieot and eoie 2018-11-21 16:46:54 +09:00
config.mak.dev Merge branch 'jk/dev-build-format-security' into maint 2018-11-21 22:57:56 +09:00
config.mak.in
config.mak.uname Merge branch 'jk/curl-ldflags' 2018-11-18 18:23:53 +09:00
configure.ac Merge branch 'dd/poll-dot-h' 2018-11-19 16:24:41 +09:00
connect.c
connect.h
connected.c
connected.h
convert.c
convert.h
copy.c
credential-cache--daemon.c
credential-cache.c
credential-store.c
credential.c
credential.h
csum-file.c
csum-file.h
ctype.c
daemon.c
date.c approxidate: fix NULL dereference in date_time() 2018-11-07 11:04:06 +09:00
decorate.c
decorate.h
delta-islands.c
delta-islands.h
delta.h
detect-compiler
diff-delta.c
diff-lib.c
diff-no-index.c
diff.c Merge branch 'js/diff-notice-has-drive-prefix' into maint 2018-11-21 22:57:51 +09:00
diff.h
diffcore-break.c
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c Merge branch 'jk/xdiff-interface' 2018-11-13 22:37:27 +09:00
diffcore-rename.c
diffcore.h
dir-iterator.c
dir-iterator.h
dir.c
dir.h
editor.c
entry.c Merge branch 'nd/clone-case-smashing-warning' 2018-11-21 20:39:03 +09:00
environment.c Merge branch 'js/mingw-perl5lib' 2018-11-13 22:37:20 +09:00
exec-cmd.c
exec-cmd.h
fast-import.c Upcast size_t variables to uintmax_t when printing 2018-11-12 16:43:52 +09:00
fetch-negotiator.c
fetch-negotiator.h
fetch-object.c
fetch-object.h
fetch-pack.c
fetch-pack.h
fmt-merge-msg.h
fsck.c
fsck.h
fsmonitor.c
fsmonitor.h
fuzz-pack-headers.c
fuzz-pack-idx.c
generate-cmdlist.sh
gettext.c i18n: make GETTEXT_POISON a runtime option 2018-11-09 11:25:19 +09:00
gettext.h i18n: make GETTEXT_POISON a runtime option 2018-11-09 11:25:19 +09:00
git-add--interactive.perl
git-archimport.perl
git-bisect.sh
git-compat-util.h Merge branch 'cc/delta-islands' 2018-11-21 20:39:02 +09:00
git-cvsexportcommit.perl
git-cvsimport.perl
git-cvsserver.perl
git-difftool--helper.sh
git-filter-branch.sh
git-instaweb.sh
git-legacy-rebase.sh git-legacy-rebase: simplify unnecessary triply-nested if 2018-12-28 12:49:48 -08:00
git-merge-octopus.sh
git-merge-one-file.sh
git-merge-resolve.sh
git-mergetool--lib.sh
git-mergetool.sh
git-p4.py
git-parse-remote.sh
git-quiltimport.sh
git-rebase--am.sh rebase: define linearization ordering and enforce it 2018-12-28 12:49:48 -08:00
git-rebase--common.sh git-rebase, sequencer: extend --quiet option for the interactive machinery 2018-12-28 12:49:48 -08:00
git-rebase--merge.sh rebase: define linearization ordering and enforce it 2018-12-28 12:49:48 -08:00
git-rebase--preserve-merges.sh
git-remote-testgit.sh
git-request-pull.sh
git-send-email.perl Merge branch 'nd/complete-format-patch' 2018-11-13 22:37:28 +09:00
git-sh-i18n.sh i18n: make GETTEXT_POISON a runtime option 2018-11-09 11:25:19 +09:00
git-sh-setup.sh
git-stash.sh
git-submodule.sh Merge branch 'ao/submodule-wo-gitmodules-checked-out' 2018-11-13 22:37:22 +09:00
git-svn.perl
git-web--browse.sh
git.c
git.rc
gpg-interface.c Merge branch 'mg/gpg-fingerprint' 2018-11-03 00:53:58 +09:00
gpg-interface.h
graph.c Merge branch 'np/log-graph-octopus-fix' into maint 2018-11-21 22:57:49 +09:00
graph.h
grep.c grep: remove #ifdef NO_PTHREADS 2018-11-05 13:42:11 +09:00
grep.h grep: remove #ifdef NO_PTHREADS 2018-11-05 13:42:11 +09:00
hash.h
hashmap.c
hashmap.h
help.c help -a: handle aliases with long names gracefully 2018-12-12 17:18:38 +09:00
help.h help.h: fix coding style 2018-12-12 17:18:29 +09:00
hex.c
http-backend.c
http-fetch.c
http-push.c Upcast size_t variables to uintmax_t when printing 2018-11-12 16:43:52 +09:00
http-walker.c
http.c i18n: fix small typos 2018-11-29 15:45:31 +09:00
http.h
ident.c
imap-send.c
interdiff.c
interdiff.h
iterator.h
json-writer.c
json-writer.h
khash.h
kwset.c
kwset.h
levenshtein.c
levenshtein.h
line-log.c
line-log.h
line-range.c
line-range.h
linear-assignment.c
linear-assignment.h
list-objects-filter-options.c
list-objects-filter-options.h
list-objects-filter.c
list-objects-filter.h
list-objects.c
list-objects.h
list.h
ll-merge.c
ll-merge.h
lockfile.c
lockfile.h
log-tree.c range-diff: always pass at least minimal diff options 2018-12-04 10:36:14 +09:00
log-tree.h
ls-refs.c
ls-refs.h
mailinfo.c
mailinfo.h
mailmap.c
mailmap.h
match-trees.c
mem-pool.c
mem-pool.h
merge-blobs.c
merge-blobs.h
merge-recursive.c Merge branch 'en/double-semicolon-fix' into maint 2018-11-21 22:57:55 +09:00
merge-recursive.h
merge.c
mergesort.c
mergesort.h
midx.c i18n: fix small typos 2018-11-29 15:45:31 +09:00
midx.h Merge branch 'ds/test-multi-pack-index' 2018-11-13 22:37:19 +09:00
name-hash.c Clean up pthread_create() error handling 2018-11-05 13:42:11 +09:00
notes-cache.c
notes-cache.h
notes-merge.c
notes-merge.h
notes-utils.c
notes-utils.h
notes.c
notes.h
object-store.h
object.c
object.h
oidmap.c
oidmap.h
oidset.c
oidset.h
pack-bitmap-write.c
pack-bitmap.c
pack-bitmap.h
pack-check.c
pack-objects.c
pack-objects.h Merge branch 'cc/delta-islands' 2018-11-21 20:39:02 +09:00
pack-revindex.c
pack-revindex.h
pack-write.c
pack.h
packfile.c Merge branch 'ds/test-multi-pack-index' 2018-11-13 22:37:19 +09:00
packfile.h
pager.c
parse-options-cb.c assert NOARG/NONEG behavior of parse-options callbacks 2018-11-06 12:56:29 +09:00
parse-options.c Merge branch 'nd/show-gitcomp-compilation-fix' into maint 2018-12-15 12:24:33 +09:00
parse-options.h Merge branch 'nd/show-gitcomp-compilation-fix' into maint 2018-12-15 12:24:33 +09:00
patch-delta.c
patch-ids.c
patch-ids.h
path.c Merge branch 'tb/char-may-be-unsigned' into maint 2018-11-21 22:58:09 +09:00
path.h
pathspec.c
pathspec.h
pkt-line.c
pkt-line.h
preload-index.c Merge branch 'nd/pthreads' 2018-11-18 18:23:52 +09:00
pretty.c Merge branch 'jk/trailer-fixes' into maint 2018-11-21 22:57:42 +09:00
pretty.h
prio-queue.c
prio-queue.h
progress.c
progress.h
prompt.c
prompt.h
protocol.c
protocol.h
quote.c
quote.h
range-diff.c format-patch: do not let its diff-options affect --range-diff 2018-11-30 13:47:55 +09:00
range-diff.h format-patch: do not let its diff-options affect --range-diff 2018-11-30 13:47:55 +09:00
reachable.c
reachable.h
read-cache.c Merge branch 'cc/shared-index-permbits' 2018-11-21 20:39:03 +09:00
rebase-interactive.c
rebase-interactive.h
ref-filter.c Merge branch 'jk/trailer-fixes' into maint 2018-11-21 22:57:42 +09:00
ref-filter.h
reflog-walk.c
reflog-walk.h
refs.c Merge branch 'ds/commit-graph-with-grafts' into maint 2018-11-21 22:57:47 +09:00
refs.h Merge branch 'ds/commit-graph-with-grafts' into maint 2018-11-21 22:57:47 +09:00
refspec.c
refspec.h
remote-curl.c Merge branch 'en/double-semicolon-fix' into maint 2018-11-21 22:57:55 +09:00
remote-testsvn.c
remote.c
remote.h
replace-object.c Merge branch 'ds/commit-graph-with-grafts' into maint 2018-11-21 22:57:47 +09:00
replace-object.h
repository.c
repository.h
rerere.c Merge branch 'en/rerere-multi-stage-1-fix' into maint 2018-11-21 22:57:44 +09:00
rerere.h
resolve-undo.c
resolve-undo.h
revision.c Merge branch 'md/exclude-promisor-objects-fix' into maint 2018-11-21 22:57:52 +09:00
revision.h Merge branch 'md/exclude-promisor-objects-fix' into maint 2018-11-21 22:57:52 +09:00
run-command.c Merge branch 'jc/run-command-report-exec-failure-fix' into maint 2018-12-15 12:24:34 +09:00
run-command.h send-pack.c: move async's #ifdef NO_PTHREADS back to run-command.c 2018-11-05 13:42:11 +09:00
send-pack.c send-pack.c: move async's #ifdef NO_PTHREADS back to run-command.c 2018-11-05 13:42:11 +09:00
send-pack.h
sequencer.c git-rebase, sequencer: extend --quiet option for the interactive machinery 2018-12-28 12:49:48 -08:00
sequencer.h git-rebase, sequencer: extend --quiet option for the interactive machinery 2018-12-28 12:49:48 -08:00
serve.c
serve.h
server-info.c
setup.c
sh-i18n--envsubst.c
sha1-array.c
sha1-array.h
sha1-file.c Merge branch 'jk/detect-truncated-zlib-input' into maint 2018-11-21 22:57:52 +09:00
sha1-lookup.c
sha1-lookup.h
sha1-name.c
sha1dc_git.c
sha1dc_git.h
shallow.c Merge branch 'js/shallow-and-fetch-prune' 2018-11-06 15:50:18 +09:00
shell.c
shortlog.h
sideband.c
sideband.h
sigchain.c
sigchain.h
split-index.c
split-index.h
strbuf.c
strbuf.h
streaming.c
streaming.h
string-list.c Merge branch 'sb/string-list-remove-unused' into maint 2018-11-21 22:57:56 +09:00
string-list.h
sub-process.c
sub-process.h
submodule-config.c Merge branch 'ao/submodule-wo-gitmodules-checked-out' 2018-11-13 22:37:22 +09:00
submodule-config.h
submodule.c Merge branch 'sm/show-superproject-while-conflicted' into maint 2018-11-21 22:57:48 +09:00
submodule.h Merge branch 'ao/submodule-wo-gitmodules-checked-out' 2018-11-13 22:37:22 +09:00
symlinks.c
tag.c
tag.h
tar.h
tempfile.c
tempfile.h Merge branch 'jk/reopen-tempfile-truncate' into maint 2018-11-21 22:57:43 +09:00
thread-utils.c
thread-utils.h
tmp-objdir.c
tmp-objdir.h
trace.c
trace.h
trailer.c
trailer.h Merge branch 'jk/trailer-fixes' into maint 2018-11-21 22:57:42 +09:00
transport-helper.c Merge branch 'nd/n18n-fix' 2018-11-29 16:28:39 +09:00
transport-internal.h
transport.c Merge branch 'nd/submodule-unused-vars' 2018-11-06 15:50:20 +09:00
transport.h
tree-diff.c
tree-walk.c Merge branch 'nd/tree-walk-path-exclusion' 2018-11-13 22:37:28 +09:00
tree-walk.h
tree.c
tree.h
unicode-width.h
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c
unpack-trees.h
upload-pack.c Merge branch 'jk/uploadpack-packobjectshook-fix' into maint 2018-11-21 22:58:09 +09:00
upload-pack.h
url.c
url.h
urlmatch.c
urlmatch.h
usage.c
userdiff.c
userdiff.h
utf8.c
utf8.h
varint.c
varint.h
version.c
version.h
versioncmp.c
walker.c
walker.h
wildmatch.c
wildmatch.h
worktree.c Merge branch 'nd/per-worktree-ref-iteration' 2018-11-13 22:37:26 +09:00
worktree.h Merge branch 'nd/per-worktree-ref-iteration' 2018-11-13 22:37:26 +09:00
wrap-for-bin.sh
wrapper.c
write-or-die.c
ws.c
wt-status.c status: rebase and merge can be in progress at the same time 2018-11-13 12:04:00 +09:00
wt-status.h
xdiff-interface.c Merge branch 'jk/xdiff-interface' 2018-11-13 22:37:27 +09:00
xdiff-interface.h xdiff-interface: drop parse_hunk_header() 2018-11-05 13:14:35 +09:00
zlib.c

README.md

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-.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 https://public-inbox.org/git/, http://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