Git with broken hash generation to generate collisions between object IDs. Don't use this!
https://undefinedbehavior.de/posts/commit-vandalism/
2db1a43f41
When pack-objects is computing the reachability bitmap to
serve a fetch request, it can erroneously die() if some of
the UNINTERESTING objects are not present. Upload-pack
throws away HAVE lines from the client for objects we do not
have, but we may have a tip object without all of its
ancestors (e.g., if the tip is no longer reachable and was
new enough to survive a `git prune`, but some of its
reachable objects did get pruned).
In the non-bitmap case, we do a revision walk with the HAVE
objects marked as UNINTERESTING. The revision walker
explicitly ignores errors in accessing UNINTERESTING commits
to handle this case (and we do not bother looking at
UNINTERESTING trees or blobs at all).
When we have bitmaps, however, the process is quite
different. The bitmap index for a pack-objects run is
calculated in two separate steps:
First, we perform an extensive walk from all the HAVEs to
find the full set of objects reachable from them. This walk
is usually optimized away because we are expected to hit an
object with a bitmap during the traversal, which allows us
to terminate early.
Secondly, we perform an extensive walk from all the WANTs,
which usually also terminates early because we hit a commit
with an existing bitmap.
Once we have the resulting bitmaps from the two walks, we
AND-NOT them together to obtain the resulting set of objects
we need to pack.
When we are walking the HAVE objects, the revision walker
does not know that we are walking it only to mark the
results as uninteresting. We strip out the UNINTERESTING flag,
because those objects _are_ interesting to us during the
first walk. We want to keep going to get a complete set of
reachable objects if we can.
We need some way to tell the revision walker that it's OK to
silently truncate the HAVE walk, just like it does for the
UNINTERESTING case. This patch introduces a new
`ignore_missing_links` flag to the `rev_info` struct, which
we set only for the HAVE walk.
It also adds tests to cover UNINTERESTING objects missing
from several positions: a missing blob, a missing tree, and
a missing parent commit. The missing blob already worked (as
we do not care about its contents at all), but the other two
cases caused us to die().
Note that there are a few cases we do not need to test:
1. We do not need to test a missing tree, with the blob
still present. Without the tree that refers to it, we
would not know that the blob is relevant to our walk.
2. We do not need to test a tip commit that is missing.
Upload-pack omits these for us (and in fact, we
complain even in the non-bitmap case if it fails to do
so).
Reported-by: Siddharth Agarwal <sid0@fb.com>
Signed-off-by: Vicent Marti <tanoku@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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|---|---|---|
| block-sha1 | ||
| builtin | ||
| compat | ||
| contrib | ||
| Documentation | ||
| ewah | ||
| git-gui | ||
| gitk-git | ||
| gitweb | ||
| mergetools | ||
| perl | ||
| po | ||
| ppc | ||
| t | ||
| templates | ||
| vcs-svn | ||
| xdiff | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| abspath.c | ||
| aclocal.m4 | ||
| advice.c | ||
| advice.h | ||
| alias.c | ||
| alloc.c | ||
| archive-tar.c | ||
| archive-zip.c | ||
| archive.c | ||
| archive.h | ||
| argv-array.c | ||
| argv-array.h | ||
| attr.c | ||
| attr.h | ||
| base85.c | ||
| bisect.c | ||
| 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 | ||
| check_bindir | ||
| check-builtins.sh | ||
| check-racy.c | ||
| color.c | ||
| color.h | ||
| column.c | ||
| column.h | ||
| combine-diff.c | ||
| command-list.txt | ||
| commit-slab.h | ||
| commit.c | ||
| commit.h | ||
| config.c | ||
| config.mak.in | ||
| config.mak.uname | ||
| configure.ac | ||
| connect.c | ||
| connect.h | ||
| connected.c | ||
| connected.h | ||
| convert.c | ||
| convert.h | ||
| copy.c | ||
| COPYING | ||
| 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 | ||
| 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.c | ||
| dir.h | ||
| editor.c | ||
| entry.c | ||
| environment.c | ||
| exec_cmd.c | ||
| exec_cmd.h | ||
| fast-import.c | ||
| fetch-pack.c | ||
| fetch-pack.h | ||
| fmt-merge-msg.h | ||
| fsck.c | ||
| fsck.h | ||
| generate-cmdlist.sh | ||
| gettext.c | ||
| gettext.h | ||
| git-add--interactive.perl | ||
| git-am.sh | ||
| git-archimport.perl | ||
| git-bisect.sh | ||
| git-compat-util.h | ||
| git-cvsexportcommit.perl | ||
| git-cvsimport.perl | ||
| git-cvsserver.perl | ||
| git-difftool--helper.sh | ||
| git-difftool.perl | ||
| git-filter-branch.sh | ||
| git-instaweb.sh | ||
| git-lost-found.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-pull.sh | ||
| git-quiltimport.sh | ||
| git-rebase--am.sh | ||
| git-rebase--interactive.sh | ||
| git-rebase--merge.sh | ||
| git-rebase.sh | ||
| git-relink.perl | ||
| 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-VERSION-GEN | ||
| git-web--browse.sh | ||
| git.c | ||
| git.rc | ||
| git.spec.in | ||
| gpg-interface.c | ||
| gpg-interface.h | ||
| graph.c | ||
| graph.h | ||
| grep.c | ||
| grep.h | ||
| hash.c | ||
| hash.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 | ||
| INSTALL | ||
| 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 | ||
| list-objects.c | ||
| list-objects.h | ||
| ll-merge.c | ||
| ll-merge.h | ||
| lockfile.c | ||
| log-tree.c | ||
| log-tree.h | ||
| mailmap.c | ||
| mailmap.h | ||
| Makefile | ||
| match-trees.c | ||
| 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.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 | ||
| pack.h | ||
| pager.c | ||
| parse-options-cb.c | ||
| parse-options.c | ||
| parse-options.h | ||
| patch-delta.c | ||
| patch-ids.c | ||
| patch-ids.h | ||
| path.c | ||
| pathspec.c | ||
| pathspec.h | ||
| pkt-line.c | ||
| pkt-line.h | ||
| preload-index.c | ||
| pretty.c | ||
| prio-queue.c | ||
| prio-queue.h | ||
| progress.c | ||
| progress.h | ||
| prompt.c | ||
| prompt.h | ||
| quote.c | ||
| quote.h | ||
| reachable.c | ||
| reachable.h | ||
| read-cache.c | ||
| README | ||
| reflog-walk.c | ||
| reflog-walk.h | ||
| refs.c | ||
| refs.h | ||
| RelNotes | ||
| remote-curl.c | ||
| remote-testsvn.c | ||
| remote.c | ||
| remote.h | ||
| replace_object.c | ||
| 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 | ||
| server-info.c | ||
| setup.c | ||
| sh-i18n--envsubst.c | ||
| sha1_file.c | ||
| sha1_name.c | ||
| sha1-array.c | ||
| sha1-array.h | ||
| sha1-lookup.c | ||
| sha1-lookup.h | ||
| shallow.c | ||
| shell.c | ||
| shortlog.h | ||
| show-index.c | ||
| sideband.c | ||
| sideband.h | ||
| sigchain.c | ||
| sigchain.h | ||
| strbuf.c | ||
| strbuf.h | ||
| streaming.c | ||
| streaming.h | ||
| string-list.c | ||
| string-list.h | ||
| submodule.c | ||
| submodule.h | ||
| symlinks.c | ||
| tag.c | ||
| tag.h | ||
| tar.h | ||
| test-chmtime.c | ||
| test-ctype.c | ||
| test-date.c | ||
| test-delta.c | ||
| test-dump-cache-tree.c | ||
| test-genrandom.c | ||
| test-index-version.c | ||
| test-line-buffer.c | ||
| test-match-trees.c | ||
| test-mergesort.c | ||
| test-mktemp.c | ||
| test-parse-options.c | ||
| test-path-utils.c | ||
| test-prio-queue.c | ||
| test-read-cache.c | ||
| test-regex.c | ||
| test-revision-walking.c | ||
| test-run-command.c | ||
| test-scrap-cache-tree.c | ||
| test-sha1.c | ||
| test-sha1.sh | ||
| test-sigchain.c | ||
| test-string-list.c | ||
| test-subprocess.c | ||
| test-svn-fe.c | ||
| test-urlmatch-normalization.c | ||
| test-wildmatch.c | ||
| thread-utils.c | ||
| thread-utils.h | ||
| trace.c | ||
| transport-helper.c | ||
| transport.c | ||
| transport.h | ||
| tree-diff.c | ||
| tree-walk.c | ||
| tree-walk.h | ||
| tree.c | ||
| tree.h | ||
| unimplemented.sh | ||
| unix-socket.c | ||
| unix-socket.h | ||
| unpack-trees.c | ||
| unpack-trees.h | ||
| upload-pack.c | ||
| 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 | ||
| walker.c | ||
| walker.h | ||
| wildmatch.c | ||
| wildmatch.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 - the stupid content tracker
////////////////////////////////////////////////////////////////
"git" can mean anything, 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
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.
See Documentation/gittutorial.txt to get started, then see
Documentation/everyday.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).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
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.