Git with broken hash generation to generate collisions between object IDs. Don't use this!
https://undefinedbehavior.de/posts/commit-vandalism/
7cae7627c4
Turn on sparse index and remove ensure_full_index(). Before this patch, `git-grep` utilizes the ensure_full_index() method to expand the index and search all the entries. Because this method requires walking all the trees and constructing the index, it is the slow part within the whole command. To achieve better performance, this patch uses grep_tree() to search the sparse directory entries and get rid of the ensure_full_index() method. Why grep_tree() is a better choice over ensure_full_index()? 1) grep_tree() is as correct as ensure_full_index(). grep_tree() looks into every sparse-directory entry (represented by a tree) recursively when looping over the index, and the result of doing so matches the result of expanding the index. 2) grep_tree() utilizes pathspecs to limit the scope of searching. ensure_full_index() always expands the index, which means it will always walk all the trees and blobs in the repo without caring if the user only wants a subset of the content, i.e. using a pathspec. On the other hand, grep_tree() will only search the contents that match the pathspec, and thus possibly walking fewer trees. 3) grep_tree() does not construct and copy back a new index, while ensure_full_index() does. This also saves some time. ---------------- Performance test - Summary: p2000 tests demonstrate a ~71% execution time reduction for `git grep --cached bogus -- "f2/f1/f1/*"` using tree-walking logic. However, notice that this result varies depending on the pathspec given. See below "Command used for testing" for more details. Test HEAD~ HEAD ------------------------------------------------------- 2000.78: git grep ... (full-v3) 0.35 0.39 (≈) 2000.79: git grep ... (full-v4) 0.36 0.30 (≈) 2000.80: git grep ... (sparse-v3) 0.88 0.23 (-73.8%) 2000.81: git grep ... (sparse-v4) 0.83 0.26 (-68.6%) - Command used for testing: git grep --cached bogus -- "f2/f1/f1/*" The reason for specifying a pathspec is that, if we don't specify a pathspec, then grep_tree() will walk all the trees and blobs to find the pattern, and the time consumed doing so is not too different from using the original ensure_full_index() method, which also spends most of the time walking trees. However, when a pathspec is specified, this latest logic will only walk the area of trees enclosed by the pathspec, and the time consumed is reasonably a lot less. Generally speaking, because the performance gain is acheived by walking less trees, which are specified by the pathspec, the HEAD time v.s. HEAD~ time in sparse-v[3|4], should be proportional to "pathspec enclosed area" v.s. "all area", respectively. Namely, the wider the <pathspec> is encompassing, the less the performance difference between HEAD~ and HEAD, and vice versa. That is, if we don't specify a pathspec, the performance difference [1] is indistinguishable: both methods walk all the trees and take generally same amount of time (even with the index construction time included for ensure_full_index()). [1] Performance test result without pathspec (hence walking all trees): Command used: git grep --cached bogus Test HEAD~ HEAD --------------------------------------------------- 2000.78: git grep ... (full-v3) 6.17 5.19 (≈) 2000.79: git grep ... (full-v4) 6.19 5.46 (≈) 2000.80: git grep ... (sparse-v3) 6.57 6.44 (≈) 2000.81: git grep ... (sparse-v4) 6.65 6.28 (≈) -------------------------- NEEDSWORK about submodules There are a few NEEDSWORKs that belong to improvements beyond this topic. See the NEEDSWORK in builtin/grep.c::grep_submodule() for more context. The other two NEEDSWORKs in t1092 are also relative. Suggested-by: Derrick Stolee <derrickstolee@github.com> Helped-by: Derrick Stolee <derrickstolee@github.com> Helped-by: Victoria Dye <vdye@github.com> Helped-by: Elijah Newren <newren@gmail.com> Signed-off-by: Shaoxuan Yuan <shaoxuan.yuan02@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> |
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|---|---|---|
| .github | ||
| block-sha1 | ||
| builtin | ||
| ci | ||
| compat | ||
| contrib | ||
| Documentation | ||
| ewah | ||
| git-gui | ||
| gitk-git | ||
| gitweb | ||
| mergetools | ||
| negotiator | ||
| perl | ||
| po | ||
| ppc | ||
| refs | ||
| reftable | ||
| sha1collisiondetection@855827c583 | ||
| sha1dc | ||
| sha256 | ||
| t | ||
| templates | ||
| trace2 | ||
| xdiff | ||
| .cirrus.yml | ||
| .clang-format | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| .tsan-suppressions | ||
| abspath.c | ||
| aclocal.m4 | ||
| add-interactive.c | ||
| add-interactive.h | ||
| add-patch.c | ||
| 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 | ||
| attr.c | ||
| attr.h | ||
| banned.h | ||
| base85.c | ||
| bisect.c | ||
| bisect.h | ||
| blame.c | ||
| blame.h | ||
| blob.c | ||
| blob.h | ||
| bloom.c | ||
| bloom.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 | ||
| cbtree.c | ||
| cbtree.h | ||
| chdir-notify.c | ||
| chdir-notify.h | ||
| check-builtins.sh | ||
| checkout.c | ||
| checkout.h | ||
| chunk-format.c | ||
| chunk-format.h | ||
| CODE_OF_CONDUCT.md | ||
| color.c | ||
| color.h | ||
| column.c | ||
| column.h | ||
| combine-diff.c | ||
| command-list.txt | ||
| commit-graph.c | ||
| commit-graph.h | ||
| commit-reach.c | ||
| commit-reach.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 | ||
| COPYING | ||
| credential.c | ||
| credential.h | ||
| csum-file.c | ||
| csum-file.h | ||
| ctype.c | ||
| daemon.c | ||
| date.c | ||
| date.h | ||
| decorate.c | ||
| decorate.h | ||
| delta-islands.c | ||
| delta-islands.h | ||
| delta.h | ||
| detect-compiler | ||
| diagnose.c | ||
| diagnose.h | ||
| diff-delta.c | ||
| diff-lib.c | ||
| diff-merges.c | ||
| diff-merges.h | ||
| diff-no-index.c | ||
| diff.c | ||
| diff.h | ||
| diffcore-break.c | ||
| diffcore-delta.c | ||
| diffcore-order.c | ||
| diffcore-pickaxe.c | ||
| diffcore-rename.c | ||
| diffcore-rotate.c | ||
| diffcore.h | ||
| dir-iterator.c | ||
| dir-iterator.h | ||
| dir.c | ||
| dir.h | ||
| editor.c | ||
| entry.c | ||
| entry.h | ||
| environment.c | ||
| environment.h | ||
| exec-cmd.c | ||
| exec-cmd.h | ||
| fetch-negotiator.c | ||
| fetch-negotiator.h | ||
| fetch-pack.c | ||
| fetch-pack.h | ||
| fmt-merge-msg.c | ||
| fmt-merge-msg.h | ||
| fsck.c | ||
| fsck.h | ||
| fsmonitor--daemon.h | ||
| fsmonitor-ipc.c | ||
| fsmonitor-ipc.h | ||
| fsmonitor-settings.c | ||
| fsmonitor-settings.h | ||
| fsmonitor.c | ||
| fsmonitor.h | ||
| fuzz-commit-graph.c | ||
| fuzz-pack-headers.c | ||
| fuzz-pack-idx.c | ||
| generate-cmdlist.sh | ||
| generate-configlist.sh | ||
| generate-hooklist.sh | ||
| gettext.c | ||
| gettext.h | ||
| git-add--interactive.perl | ||
| git-archimport.perl | ||
| git-bisect.sh | ||
| git-compat-util.h | ||
| git-curl-compat.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-quiltimport.sh | ||
| git-request-pull.sh | ||
| git-send-email.perl | ||
| git-sh-i18n.sh | ||
| git-sh-setup.sh | ||
| git-submodule.sh | ||
| git-svn.perl | ||
| GIT-VERSION-GEN | ||
| git-web--browse.sh | ||
| git.c | ||
| git.rc | ||
| gpg-interface.c | ||
| gpg-interface.h | ||
| graph.c | ||
| graph.h | ||
| grep.c | ||
| grep.h | ||
| hash-lookup.c | ||
| hash-lookup.h | ||
| hash.h | ||
| hashmap.c | ||
| hashmap.h | ||
| help.c | ||
| help.h | ||
| hex.c | ||
| hook.c | ||
| hook.h | ||
| http-backend.c | ||
| http-fetch.c | ||
| http-push.c | ||
| http-walker.c | ||
| http.c | ||
| http.h | ||
| ident.c | ||
| imap-send.c | ||
| INSTALL | ||
| iterator.h | ||
| json-writer.c | ||
| json-writer.h | ||
| khash.h | ||
| kwset.c | ||
| kwset.h | ||
| levenshtein.c | ||
| levenshtein.h | ||
| LGPL-2.1 | ||
| 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 | ||
| Makefile | ||
| match-trees.c | ||
| mem-pool.c | ||
| mem-pool.h | ||
| merge-blobs.c | ||
| merge-blobs.h | ||
| merge-ort-wrappers.c | ||
| merge-ort-wrappers.h | ||
| merge-ort.c | ||
| merge-ort.h | ||
| merge-recursive.c | ||
| merge-recursive.h | ||
| merge.c | ||
| mergesort.h | ||
| midx.c | ||
| midx.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-file.c | ||
| object-name.c | ||
| object-store.h | ||
| object.c | ||
| object.h | ||
| oid-array.c | ||
| oid-array.h | ||
| oidmap.c | ||
| oidmap.h | ||
| oidset.c | ||
| oidset.h | ||
| oidtree.c | ||
| oidtree.h | ||
| pack-bitmap-write.c | ||
| pack-bitmap.c | ||
| pack-bitmap.h | ||
| pack-check.c | ||
| pack-mtimes.c | ||
| pack-mtimes.h | ||
| pack-objects.c | ||
| pack-objects.h | ||
| pack-revindex.c | ||
| pack-revindex.h | ||
| pack-write.c | ||
| pack.h | ||
| packfile.c | ||
| packfile.h | ||
| pager.c | ||
| parallel-checkout.c | ||
| parallel-checkout.h | ||
| 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 | ||
| promisor-remote.c | ||
| promisor-remote.h | ||
| prompt.c | ||
| prompt.h | ||
| protocol-caps.c | ||
| protocol-caps.h | ||
| protocol.c | ||
| protocol.h | ||
| prune-packed.c | ||
| prune-packed.h | ||
| quote.c | ||
| quote.h | ||
| range-diff.c | ||
| range-diff.h | ||
| reachable.c | ||
| reachable.h | ||
| read-cache.c | ||
| README.md | ||
| rebase-interactive.c | ||
| rebase-interactive.h | ||
| rebase.c | ||
| rebase.h | ||
| ref-filter.c | ||
| ref-filter.h | ||
| reflog-walk.c | ||
| reflog-walk.h | ||
| reflog.c | ||
| reflog.h | ||
| refs.c | ||
| refs.h | ||
| refspec.c | ||
| refspec.h | ||
| RelNotes | ||
| remote-curl.c | ||
| remote.c | ||
| remote.h | ||
| replace-object.c | ||
| replace-object.h | ||
| repo-settings.c | ||
| repository.c | ||
| repository.h | ||
| rerere.c | ||
| rerere.h | ||
| reset.c | ||
| reset.h | ||
| resolve-undo.c | ||
| resolve-undo.h | ||
| revision.c | ||
| revision.h | ||
| run-command.c | ||
| run-command.h | ||
| SECURITY.md | ||
| send-pack.c | ||
| send-pack.h | ||
| sequencer.c | ||
| sequencer.h | ||
| serve.c | ||
| serve.h | ||
| server-info.c | ||
| setup.c | ||
| sh-i18n--envsubst.c | ||
| sha1dc_git.c | ||
| sha1dc_git.h | ||
| shallow.c | ||
| shallow.h | ||
| shared.mak | ||
| shell.c | ||
| shortlog.h | ||
| sideband.c | ||
| sideband.h | ||
| sigchain.c | ||
| sigchain.h | ||
| simple-ipc.h | ||
| sparse-index.c | ||
| sparse-index.h | ||
| split-index.c | ||
| split-index.h | ||
| stable-qsort.c | ||
| strbuf.c | ||
| strbuf.h | ||
| streaming.c | ||
| streaming.h | ||
| string-list.c | ||
| string-list.h | ||
| strmap.c | ||
| strmap.h | ||
| strvec.c | ||
| strvec.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 | ||
| trace2.c | ||
| trace2.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 | ||
| unix-stream-server.c | ||
| unix-stream-server.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 | ||
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).
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 with just "subscribe git" in the body to majordomo@vger.kernel.org (not the Git list). The mailing list archives are available at https://lore.kernel.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