Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of
text editors" <bug-gnu-emacs@gnu.org> writes:

>> @@ -2150,24 +2150,26 @@ comint-output-filter
>>  	    ;; insert-before-markers is a bad thing. XXX
>>  	    ;; Luckily we don't have to use it any more, we use
>>  	    ;; window-point-insertion-type instead.
>> -	    (insert string)
>> +	    (make-local-variable 'jit-lock-mode)
>> +	    (let ((jit-lock-mode nil))
>> +	      (insert string)
>
> Yuck!
> Oh, and this will fail to do what it intends if the user has set
> `font-lock-support-mode` t nil: don't confuse font-lock and jit-lock.
>
> Also, I suspect that the above is not sufficient if you edit earlier
> parts of the buffer (presumably previous inputs) which may cause later
> parts to be *re*fontified.
>
> A better way might be to change the font-lock rules to skip any text
> that is marked as being output (e.g. by testing if the `field` property
> is set to `output`).
>
>
>         Stefan

Thanks for feedback, discussion continued at
https://lists.gnu.org/r/emacs-devel/2022-10/msg00005.html.