bug#58518: 29.0.50; [PATCH] Turning off compilation-minor-mode removes fontification of other modes

[Lars Ingebrigtsen <larsi@gnus.org>]

miha@kamnitnik.top writes:

> The attached patch makes them return to the face they had after step 2,
> as specified by the grep command.
[...]

> -    `(font-lock-face ,(if leave
> -                          compilation-leave-directory-face
> -                        compilation-enter-directory-face)
> +    `(compilation-face ,(if leave
> +                            compilation-leave-directory-face

[...]

> +  (let ((alist (copy-alist char-property-alias-alist)))
> +    (cl-pushnew 'compilation-face (alist-get 'face alist))

Hm, it's an interesting approach -- we don't use this trick elsewhere in
other mode (I mean, except for `font-lock-face'), but this seems like a
good solution.

But since it's so unusual, I wonder whether there's any reason we don't
use this more in general.  Are there performance impacts, for instance?
(I don't think so, since it's a buffer-local variable.)  But I've added
Stefan and Eli to the CCs; perhaps they have comments.