[BUG] git crashes on simple rev-parse incantation

$ git --version
git version 2.34.1
$ uname -a
Linux zed 5.15.0-48-generic #54-Ubuntu SMP Fri Aug 26 13:26:29 UTC
2022 x86_64 x86_64 x86_64 GNU/Linux

I get:

$ git rev-parse --parseopt -- <<<$'x\n--\n=, x\n'
fatal: Out of memory, malloc failed (tried to allocate
18446744073709551615 bytes)

----
Here's a less cryptic that fails the same way:

OPTS_SPEC="\
some-command [<options>] <args>...

some-command does foo and bar!
--
h,help    show the help
=,equal   nooooooooooooo!
"

echo "$OPTS_SPEC" |
  git rev-parse --parseopt --

----
'=' as a short form in the opts spec seems to be the culprit.

I was trying to see what short options could be parsed like '-9',
'-_', '-+', etc.

In addition to '=', '!' and '*' also cause crashes.
I tested all the other ascii punctuation and didn't see crashes.