Subject: bug#39597: 27.0.60: M-x occur adds fontification to fundamental-mode

From: Kévin Le Gouguec <[email-masked]>
Date: Fri, 21 Feb 2020 20:09:41 +0100

Eli Zaretskii <[email-masked]> writes:

> The fix installed on master

(If you are referring to Stefan's patch, AFAICT it has not been
committed to master yet.)

>                             is in a much more general place, and will
> affect much more than just occur-engine.  I'm okay with a bug-fix
> change on the release branch which is local to this place in
> replace.el, but I don't want to risk breaking unrelated code by
> changing font-lock.el.

Idle musing: I wonder if something could be done inside
fundamental-mode.  It's not the only fontification issue I've noticed
there[1].

> Another alternative is to revert the offending changes in fb16313025
> on the release branch.  Since it is an enhancement, perhaps we could
> live without it in Emacs 27.

I don't have a preference about that.  Juri?

[1] E.g. (I was about to report this as a distinct issue… someday…)

    C-x b foo
    foo RET bar RET baz RET
    M-s h r a RET RET
    aaaa

    ⇒ In all modes *but* fundamental-mode, hi-lock-mode dynamically
    highlights new matches (e.g. the added "aaaa" string here).

    This bug is not strictly related to the current one, since the
    former has been with us since at least 26.3, but that does make me
    wonder whether both issues could be solved by turning some font-lock
    knob in fundamental-mode…