There are two bugs that sort of work together and cause
problems. Let's start with one in replace_each_worktree_head_symref.
Before fa099d2322 (worktree.c: kill parse_ref() in favor of
refs_resolve_ref_unsafe() - 2017-04-24), this code looks like this:
if (strcmp(oldref, worktrees[i]->head_ref))
continue;
set_worktree_head_symref(...);
After fa099d2322, it is possible that head_ref can be NULL. However,
the updated code takes the wrong exit. In the error case (NULL
head_ref), we should "continue;" to the next worktree. The updated
code makes us _skip_ "continue;" and update HEAD anyway.
The NULL head_ref is triggered by the second bug in add_head_info (in
the same commit). With the flag RESOLVE_REF_READING, resolve_ref_unsafe()
will abort if it cannot resolve the target ref. For orphan checkouts,
HEAD always points to an unborned branch, resolving target ref will
always fail. Now we have NULL head_ref. Now we always update HEAD.
Correct the logic in replace_ function so that we don't accidentally
update HEAD on error. As it turns out, correcting the logic bug above
breaks branch renaming completely, thanks to the second bug.
"git branch -[Mm]" does two steps (on a normal checkout, no orphan!):
- rename the branch on disk (e.g. refs/heads/abc to refs/heads/def)
- update HEAD if it points to the branch being renamed.
At the second step, since the branch pointed to by HEAD (e.g. "abc") no
longer exists on disk, we run into a temporary orphan checkout situation
that has been just corrected to _not_ update HEAD. But we need to update
HEAD since it's not actually an orphan checkout. We need to update HEAD
to move out of that orphan state.
Correct add_head_info(), remove RESOLVE_REF_READING flag. With the flag
gone, we should always return good "head_ref" in orphan checkouts (either
temporary or permanent). With good head_ref, things start to work again.
Noticed-by: Nish Aravamudan <nish.aravamudan@canonical.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@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-.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.
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