bug#53294: 29.0.50; Indirect font changes incorrectly affecting original buffer

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Andrew Hyatt <ahyatt@gmail.com>,  53294@debbugs.gnu.org
> Date: Sun, 16 Jan 2022 12:11:39 -0500
> 
> Some ways we can fix this:
> 
> - In `face-remap.el`, refrain from modifying the `face-remapping-alist`
>   by side-effects (i.e. avoid `delq`, `setcdr`, and friends).
> 
> - Add a `make-indirect-buffer-hook` and arrange for `face-remap.el` to
>   add a function there that does a deep enough copy of
>   `face-remapping-alist`.
> 
> - Remember that indirect buffers are an attractive nuisance and should
>   be deprecated (but note that I suspect the same bug affects
>   `clone-buffer` because it doesn't make a deep enough copy of
>   `face-remapping-alist` either).

The last one tells me we are better with leaving this sleeping dog
lie.