Eli Zaretskii <
eliz@gnu.org> schrieb am Mi., 14. Sep. 2016 um 21:24 Uhr:
> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Wed, 14 Sep 2016 18:43:13 +0000
> Cc: 21730@debbugs.gnu.org, mwd@md5i.com
>
> Since the problem that caused the patch to be reverted was with
> narrowing, why not simply use
>
> (= point (with-current-buffer (window-buffer window) (point-min)))
>
> instead of
>
> (= point 1)
>
> ?
>
> This has the same issues as described above. There's more code in cursor-sensor--detect that assumes (eq
> (current-buffer) (window-buffer window)), e.g. the form (get-char-property point 'cursor-sensor-functions).
> Therefore (= point (with-current-buffer (window-buffer window) (point-min))) must be the same as (bobp).
> Another mystery is the stack trace entry "run-hook-with-args(cursor-sensor--detect #<window 224 on
> *Group*>)". How can cursor-sensor--detect be the first argument to run-hook-with-args? Shouldn't it always
> be pre-redisplay-functions?
If we want to dig deeper, I think we should first understand why bop
doesn't work. Is it indeed because the window's buffer is not the
current buffer when the hook is called?
Unfortunately the error doesn't trigger consistently. Maybe we are lucky and somebody manages to detect such an issue.
I'd also suggest to add
(cl-assert (eq (current-buffer) (window-buffer window)))
to cursor-sensor--detect, because the function relies on this equality.