c1ea48a8f7
versions could be an empty string_list. In that case, versions->items is NULL, and we shouldn't be trying to perform pointer arithmetic with it (as that results in undefined behaviour). Moreover we only use the results of this calculation once when calling QSORT. Therefore we choose to skip creating relevant_entries and call QSORT directly with our manipulated pointers (but only if there's data requiring sorting). This lets us avoid abusing the string_list API, and saves us from having to explain why this abuse is OK. Finally, an assertion is added to make sure that write_tree() is called with a valid offset. This issue has probably existed since: ee4012dcf9 (merge-ort: step 2 of tree writing -- function to create tree object, 2020-12-13) But it only started occurring during tests since tests started using merge-ort: f3b964a07e (Add testing with merge-ort merge strategy, 2021-03-20) For reference - here's the original UBSAN commit that implemented this check, it sounds like this behaviour isn't actually likely to cause any issues (but we might as well fix it regardless): https://reviews.llvm.org/D67122 UBSAN output from t3404 or t5601: merge-ort.c:2669:43: runtime error: applying zero offset to null pointer #0 0x78bb53 in write_tree merge-ort.c:2669:43 #1 0x7856c9 in process_entries merge-ort.c:3303:2 #2 0x782317 in merge_ort_nonrecursive_internal merge-ort.c:3744:2 #3 0x77feef in merge_incore_nonrecursive merge-ort.c:3853:2 #4 0x6f6a5c in do_recursive_merge sequencer.c:640:3 #5 0x6f6a5c in do_pick_commit sequencer.c:2221:9 #6 0x6ef055 in single_pick sequencer.c:4814:9 #7 0x6ef055 in sequencer_pick_revisions sequencer.c:4867:10 #8 0x4fb392 in run_sequencer revert.c:225:9 #9 0x4fa5b0 in cmd_revert revert.c:235:8 #10 0x42abd7 in run_builtin git.c:453:11 #11 0x429531 in handle_builtin git.c:704:3 #12 0x4282fb in run_argv git.c:771:4 #13 0x4282fb in cmd_main git.c:902:19 #14 0x524b63 in main common-main.c:52:11 #15 0x7fc2ca340349 in __libc_start_main (/lib64/libc.so.6+0x24349) #16 0x4072b9 in _start start.S:120 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior merge-ort.c:2669:43 in Signed-off-by: Andrzej Hunt <ajrhunt@google.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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). 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://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