bug#37496: 27.0.50; C-s failing to search

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 26 Sep 2019 10:54:34 +0200
> From: Jean Louis <bugs@gnu.support>
> Cc: 37496@debbugs.gnu.org
> 
> I will try to invoke edebug, but how to invoke it exactly?

First, load wdired.el (NOT wdired.elc!) manually with

   M-x load-library RET wdired.el RET

Then visit the wdired.el file with "C-x 5 f", go to the definition of
wdired-isearch-filter-read-only function, and with point anywhere
inside its definition type

   M-x edebug-defun RET

(Visiting wdired.el in a separate frame will make sure the buffer
where you invoke C-s will remain on display even if Edebug kicks in
and lets you step through the code of wdired-isearch-filter-read-only,
because Edebug will then use that other frame and leave alone the
frame where your buffer is displayed.)

Now invoke C-s.  If this displays the arrow on the left fringe of the
window where wdired.el is shown, it means that function was indeed
called.  In that case, step through the function by repeatedly
pressing SPC -- each SPC press will move to the next line -- and see
what happens there.

The expected and correct result is that either
wdired-isearch-filter-read-only is not called at all, or it is called
and returns non-nil.  If it is called and returns nil, it is the
reason why you don't find anything, because that makes Isearch skip
the match.

Thanks.