Re: text_property_stickiness() ignores `text-property-default-nonsticky'

[Stefan Monnier]

>>>>> "Dmitry" == Dmitry Kurochkin <address@hidden> writes:

> Hello.
> I am trying to make `keymap' property rear-nonsticky, so that it does
> not affect the next character after the region the property is applied
> to.  If I do it by setting rear-nonsticky text property to 't or to a
> list that contains 'keymap, it works fine:

>   (let ((map (make-sparse-keymap)))
>     (define-key map (kbd "RET") 'bug)
>     (switch-to-buffer "test")
>     (insert "123456")
>     (put-text-property 1 4 'keymap map)
>     (put-text-property (point-min) (point-max) 'rear-nonsticky '(keymap))
>     (goto-char 4)
>     (message "keymap: %s" (get-text-property (point) 'keymap))
>     (message "key-binding: %s" (key-binding (kbd "RET"))))

> But if I set `text-property-default-nonsticky' variable instead, it does
> not work:

>   (let ((map (make-sparse-keymap)))
>     (define-key map (kbd "RET") 'bug)
>     (switch-to-buffer "test")
>     (insert "123456")
>     (put-text-property 1 4 'keymap map)
>     (make-local-variable 'text-property-default-nonsticky)
>     (add-to-list 'text-property-default-nonsticky '(keymap . t))
>     (goto-char 4)
>     (message "keymap: %s" (get-text-property (point) 'keymap))
>     (message "key-binding: %s" (key-binding (kbd "RET"))))

> Looking through the code, I got down to text_property_stickiness()
> function in src/textprop.c, which is used by get_pos_property(), which
> is used by get_local_map().  There are checks for `front-sticky' and
> `rear-nonsticky' properties, but no checks for
> `text-property-default-nonsticky' variable.

Indeed.  Does the patch below fix your problem?

> Before opening false bug reports, I would like to confirm that this is
> an issue indeed, and it is not me doing something stupid.

"False" bug reports are not something you should be afraid of.
I.e. feel free to use M-x report-emacs-bug when something looks like
a bug *to you*, even if we decide that it's a not a bug from our point
of view.


        Stefan


=== modified file 'src/textprop.c'
--- src/textprop.c      2011-06-25 13:00:55 +0000
+++ src/textprop.c      2011-07-04 16:49:42 +0000
@@ -1707,10 +1707,14 @@
 {
   Lisp_Object prev_pos, front_sticky;
   int is_rear_sticky = 1, is_front_sticky = 0; /* defaults */
+  Lisp_Object default = Fassq (prop, Vtext_property_default_nonsticky);
 
   if (NILP (buffer))
     XSETBUFFER (buffer, current_buffer);
 
+  if (CONSP (default) && NILP (XCDR (default)))
+    is_rear_sticky = 0;
+
   if (XINT (pos) > BUF_BEGV (XBUFFER (buffer)))
     /* Consider previous character.  */
     {