Subject: bug#44329: 28.0.50; Crash in bidi_mirror_char on view-hello-file when no bidi-display-reordering (harfbuzz)

From: Kevin Brubeck Unhammer <[email-masked]>
Date: Fri, 30 Oct 2020 21:42:45 +0100

Eli Zaretskii <[email-masked]> čálii:

[...]

> This isn't supported: that variable is not supposed to be set nil,
> except for debugging display problems.

Is there something like make-obsolete-variable for this case that would
give a warning in init.el on this variable?

I am not the only one setting it to nil
https://github.com/search?q=setq+bidi-display-reordering+nil&type=code
https://emacs.stackexchange.com/a/21761/730 :) so a warning might stop
some other poor user from wasting half a day on a pointless debugging
mission.

(The manual also mentions the variable's effect without saying you
shouldn't set it
https://www.gnu.org/software/emacs/manual/html_node/emacs/Bidirectional-Editing.html
)