![]() Sometimes we want to suppress a coccinelle transformation inside a particular function. For example, in finding conversions of hashcmp() to oidcmp(), we should not convert the call in oidcmp() itself, since that would cause infinite recursion. We write that like this: @@ identifier f != oidcmp; expression E1, E2; @@ f(...) {... - hashcmp(E1->hash, E2->hash) + oidcmp(E1, E2) ...} to match the interior of any function _except_ oidcmp(). Unfortunately, this doesn't catch all cases (e.g., the one in sequencer.c that this patch fixes). The problem, as explained by one of the Coccinelle developers in [1], is: For transformation, A ... B requires that B occur on every execution path starting with A, unless that execution path ends up in error handling code. (eg, if (...) { ... return; }). Here your A is the start of the function. So you need a call to hashcmp on every path through the function, which fails when you add ifs. [...] Another issue with A ... B is that by default A and B should not appear in the matched region. So your original rule matches only the case where every execution path contains exactly one call to hashcmp, not more than one. One way to solve this is to put the pattern inside an angle-bracket pattern like "<... P ...>", which allows zero or more matches of P. That works (and is what this patch does), but it has one drawback: it matches more than we care about, and Coccinelle uses extra CPU. Here are timings for "make coccicheck" before and after this patch: [before] real 1m27.122s user 7m34.451s sys 0m37.330s [after] real 2m18.040s user 10m58.310s sys 0m41.549s That's not ideal, but it's more important for this to be correct than to be fast. And coccicheck is already fairly slow (and people don't run it for every single patch). So it's an acceptable tradeoff. There _is_ a better way to do it, which is to record the position at which we find hashcmp(), and then check it against the forbidden function list. Like: @@ position p : script:python() { p[0].current_element != "oidcmp" }; expression E1,E2; @@ - hashcmp@p(E1->hash, E2->hash) + oidcmp(E1, E2) This is only a little slower than the current code, and does the right thing in all cases. Unfortunately, not all builds of Coccinelle include python support (including the ones in Debian). Requiring it may mean that fewer people can easily run the tool, which is worse than it simply being a little slower. We may want to revisit this decision in the future if: - builds with python become more common - we find more uses for python support that tip the cost-benefit analysis But for now this patch sticks with the angle-bracket solution, and converts all existing cocci patches. This fixes only one missed case in the current code, though it makes a much better difference for some new rules I'm adding (converting "!hashcmp()" to "hasheq()" misses over half the possible conversions using the old form). [1] https://public-inbox.org/git/alpine.DEB.2.21.1808240652370.2344@hadrien/ Helped-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com> |
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Documentation | ||
block-sha1 | ||
builtin | ||
ci | ||
compat | ||
contrib | ||
ewah | ||
git-gui | ||
gitk-git | ||
gitweb | ||
mergetools | ||
negotiator | ||
perl | ||
po | ||
ppc | ||
refs | ||
sha1collisiondetection@232357eb2e | ||
sha1dc | ||
t | ||
templates | ||
vcs-svn | ||
xdiff | ||
.clang-format | ||
.gitattributes | ||
.gitignore | ||
.gitmodules | ||
.mailmap | ||
.travis.yml | ||
.tsan-suppressions | ||
COPYING | ||
GIT-VERSION-GEN | ||
INSTALL | ||
LGPL-2.1 | ||
Makefile | ||
README.md | ||
RelNotes | ||
abspath.c | ||
aclocal.m4 | ||
advice.c | ||
advice.h | ||
alias.c | ||
alias.h | ||
alloc.c | ||
alloc.h | ||
apply.c | ||
apply.h | ||
archive-tar.c | ||
archive-zip.c | ||
archive.c | ||
archive.h | ||
argv-array.c | ||
argv-array.h | ||
attr.c | ||
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 | ||
bundle.h | ||
cache-tree.c | ||
cache-tree.h | ||
cache.h | ||
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 | ||
command-list.txt | ||
commit-graph.c | ||
commit-graph.h | ||
commit-slab-decl.h | ||
commit-slab-impl.h | ||
commit-slab.h | ||
commit.c | ||
commit.h | ||
common-main.c | ||
config.c | ||
config.h | ||
config.mak.dev | ||
config.mak.in | ||
config.mak.uname | ||
configure.ac | ||
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 | ||
decorate.c | ||
decorate.h | ||
delta.h | ||
detect-compiler | ||
diff-delta.c | ||
diff-lib.c | ||
diff-no-index.c | ||
diff.c | ||
diff.h | ||
diffcore-break.c | ||
diffcore-delta.c | ||
diffcore-order.c | ||
diffcore-pickaxe.c | ||
diffcore-rename.c | ||
diffcore.h | ||
dir-iterator.c | ||
dir-iterator.h | ||
dir.c | ||
dir.h | ||
editor.c | ||
entry.c | ||
environment.c | ||
exec-cmd.c | ||
exec-cmd.h | ||
fast-import.c | ||
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 | ||
generate-cmdlist.sh | ||
gettext.c | ||
gettext.h | ||
git-add--interactive.perl | ||
git-archimport.perl | ||
git-bisect.sh | ||
git-compat-util.h | ||
git-cvsexportcommit.perl | ||
git-cvsimport.perl | ||
git-cvsserver.perl | ||
git-difftool--helper.sh | ||
git-filter-branch.sh | ||
git-instaweb.sh | ||
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 | ||
git-rebase--interactive.sh | ||
git-rebase--merge.sh | ||
git-rebase--preserve-merges.sh | ||
git-rebase.sh | ||
git-remote-testgit.sh | ||
git-request-pull.sh | ||
git-send-email.perl | ||
git-sh-i18n.sh | ||
git-sh-setup.sh | ||
git-stash.sh | ||
git-submodule.sh | ||
git-svn.perl | ||
git-web--browse.sh | ||
git.c | ||
git.rc | ||
gpg-interface.c | ||
gpg-interface.h | ||
graph.c | ||
graph.h | ||
grep.c | ||
grep.h | ||
hash.h | ||
hashmap.c | ||
hashmap.h | ||
help.c | ||
help.h | ||
hex.c | ||
http-backend.c | ||
http-fetch.c | ||
http-push.c | ||
http-walker.c | ||
http.c | ||
http.h | ||
ident.c | ||
imap-send.c | ||
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 | ||
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-recursive.h | ||
merge.c | ||
mergesort.c | ||
mergesort.h | ||
name-hash.c | ||
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 | ||
pack-revindex.c | ||
pack-revindex.h | ||
pack-write.c | ||
pack.h | ||
packfile.c | ||
packfile.h | ||
pager.c | ||
parse-options-cb.c | ||
parse-options.c | ||
parse-options.h | ||
patch-delta.c | ||
patch-ids.c | ||
patch-ids.h | ||
path.c | ||
path.h | ||
pathspec.c | ||
pathspec.h | ||
pkt-line.c | ||
pkt-line.h | ||
preload-index.c | ||
pretty.c | ||
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 | ||
range-diff.h | ||
reachable.c | ||
reachable.h | ||
read-cache.c | ||
ref-filter.c | ||
ref-filter.h | ||
reflog-walk.c | ||
reflog-walk.h | ||
refs.c | ||
refs.h | ||
refspec.c | ||
refspec.h | ||
remote-curl.c | ||
remote-testsvn.c | ||
remote.c | ||
remote.h | ||
replace-object.c | ||
replace-object.h | ||
repository.c | ||
repository.h | ||
rerere.c | ||
rerere.h | ||
resolve-undo.c | ||
resolve-undo.h | ||
revision.c | ||
revision.h | ||
run-command.c | ||
run-command.h | ||
send-pack.c | ||
send-pack.h | ||
sequencer.c | ||
sequencer.h | ||
serve.c | ||
serve.h | ||
server-info.c | ||
setup.c | ||
sh-i18n--envsubst.c | ||
sha1-array.c | ||
sha1-array.h | ||
sha1-file.c | ||
sha1-lookup.c | ||
sha1-lookup.h | ||
sha1-name.c | ||
sha1dc_git.c | ||
sha1dc_git.h | ||
shallow.c | ||
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 | ||
string-list.h | ||
sub-process.c | ||
sub-process.h | ||
submodule-config.c | ||
submodule-config.h | ||
submodule.c | ||
submodule.h | ||
symlinks.c | ||
tag.c | ||
tag.h | ||
tar.h | ||
tempfile.c | ||
tempfile.h | ||
thread-utils.c | ||
thread-utils.h | ||
tmp-objdir.c | ||
tmp-objdir.h | ||
trace.c | ||
trace.h | ||
trailer.c | ||
trailer.h | ||
transport-helper.c | ||
transport-internal.h | ||
transport.c | ||
transport.h | ||
tree-diff.c | ||
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.h | ||
upload-pack.c | ||
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 | ||
worktree.h | ||
wrap-for-bin.sh | ||
wrapper.c | ||
write-or-die.c | ||
ws.c | ||
wt-status.c | ||
wt-status.h | ||
xdiff-interface.c | ||
xdiff-interface.h | ||
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