The code added 0cc05b044f (usage.c: add a non-fatal bug() function to go
with BUG(), 2022-06-02) sets up two va_list variables: one to output to
stderr, and one to trace2. But the order of initialization is wrong:
va_list ap, cp;
va_copy(cp, ap);
va_start(ap, fmt);
We copy the contents of "ap" into "cp" before it is initialized, meaning
it is full of garbage. The two should be swapped.
However, there's another bug, noticed by Johannes Schindelin: we forget
to call va_end() for the copy. So instead of just fixing the copy's
initialization, let's do two separate start/end pairs. This is allowed
by the standard, and we don't need to use copy here since we have access
to the original varargs. Matching the pairs with the calls makes it more
obvious that everything is being done correctly.
Note that we do call bug_fl() in the tests, but it didn't trigger this
problem because our format string doesn't have any placeholders. So even
though we were passing a garbage va_list through the stack, nobody ever
needed to look at it. We can easily adjust one of the trace2 tests to
trigger this, both for bug() and for BUG(). The latter isn't broken, but
it's nice to exercise both a bit more. Without the fix in this patch
(but with the test change), the bug() case causes a segfault.
Signed-off-by: Jeff King <peff@peff.net>
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).
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).
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
