bug#58082: recent whitespace-mode regression for read-only buffers

[Lars Ingebrigtsen]

Kyle Meyer <kyle@kyleam.com> writes:

> Before f47a5324f44 (whitespace: Redo BoB/EoB empty line highlighting,
> 2022-09-11, bug#37467), this snippet runs without an issue:
>
>   (let ((b (generate-new-buffer "ws-read-only-test")))
>     (with-current-buffer b
>       (insert " ")
>       (setq buffer-read-only t)
>       (whitespace-mode 1))
>     (pop-to-buffer b))
>
> After that commit, activating whitespace mode fails:
>
>   whitespace--update-bob-eob: Buffer is read-only: #<buffer ws-read-only-test>
>
> Perhaps some of the additions in f47a5324f44 should let-bind
> inhibit-read-only?

Yup.  I've now done this in Emacs 29.