bug#67037: 29.1/git latest; Multiple versions of Emacs on macos consistently crash when loading a 2-line Markdown file

[Eli Zaretskii <eliz@gnu.org>]

> From: Matthew Ray <matthewhray@gmail.com>
> Date: Thu, 9 Nov 2023 23:49:46 -0600
> 
> The attached 2-line Markdown file consistently crashes Emacs 29.1 and
> a recent Git build of 30. I have rebuilt all of my Emacs plugins
> several times, uninstalled/reinstalled multiple versions of Emacs and
> tree-sitter. I narrowed down the offending Markdown file from a much
> larger file with `head` and `tail` that consistently crashes Emacs.
> Using `cat` to look at the file in M-x shell is fine.

Do you have some kind or Markdown mode installed?  If so, which one,
and where can one be downloaded?  Because Emacs 29 doesn't have such a
mode bundled, and when I visit the file you attached, I see
Fundamental mode (and no crash).

So some additional information is missing from your report.  In
general, it is best to describe all the steps needed to reproduce the
problem starting from "emacs -Q" (and loading any optional packages if
needed by hand), including all the commands you need to type in Emacs.

Thanks.