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

[Jean Louis]

* Eli Zaretskii <eliz@gnu.org> [2019-09-26 11:51]:
> > 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.


I could not edebug-defun on wdired-isearch-filter-read-only, nothing
was happening.

I could do edebug-defun on isearch-forward or C-s and then I got this
below:

Debugger entered: nil
  edebug--display-1(nil 0 before)
  edebug--display(nil 0 before)
  edebug-debugger(0 before nil)
  edebug-before(0)
  (edebug-after (edebug-before 0) 9 (isearch-mode t (edebug-after 
(edebug-before 1) 5 (not (edebug-after (edebug-before 2) 4 (null (edebug-after 
0 3 regexp-p))))) nil (edebug-after (edebug-before 6) 8 (not (edebug-after 0 7 
no-recursive-edit)))))
  (closure ((no-recursive-edit . 1) (regexp-p) t) nil (edebug-after 
(edebug-before 0) 9 (isearch-mode t (edebug-after (edebug-before 1) 5 (not 
(edebug-after (edebug-before 2) 4 (null (edebug-after 0 3 regexp-p))))) nil 
(edebug-after (edebug-before 6) 8 (not (edebug-after 0 7 
no-recursive-edit))))))()
  edebug-default-enter(isearch-forward (nil 1) (closure ((no-recursive-edit . 
1) (regexp-p) t) nil (edebug-after (edebug-before 0) 9 (isearch-mode t 
(edebug-after (edebug-before 1) 5 (not (edebug-after (edebug-before 2) 4 (null 
...)))) nil (edebug-after (edebug-before 6) 8 (not (edebug-after 0 7 
no-recursive-edit)))))))
  edebug-default-enter(isearch-forward (nil 1) (closure ((no-recursive-edit . 
1) (regexp-p) t) nil (edebug-after (edebug-before 0) 9 (isearch-mode t 
(edebug-after (edebug-before 1) 5 (not (edebug-after (edebug-before 2) 4 (null 
...)))) nil (edebug-after (edebug-before 6) 8 (not (edebug-after 0 7 
no-recursive-edit)))))))
  edebug-enter(isearch-forward (nil 1) (closure ((no-recursive-edit . 1) 
(regexp-p) t) nil (edebug-after (edebug-before 0) 9 (isearch-mode t 
(edebug-after (edebug-before 1) 5 (not (edebug-after (edebug-before 2) 4 (null 
...)))) nil (edebug-after (edebug-before 6) 8 (not (edebug-after 0 7 
no-recursive-edit)))))))
  isearch-forward(nil 1)
  funcall-interactively(isearch-forward nil 1)
  call-interactively(isearch-forward nil nil)
  command-execute(isearch-forward)

And I have observed that the isearch-forward stopped functioning after
doing not so many editing with C-x C-q, just few. Suddenly I got the
problem again.

Jean