bug#44375: Always give a message when flashing the screen

bug#44375: Always give a message when flashing the screen

[積丹尼 Dan Jacobson]

Always give a message when flashing the screen. See e.g., bug 44340
(Archived rather fast.)

bug#44375: Always give a message when flashing the screen

[Stefan Kangas]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> Always give a message when flashing the screen. See e.g., bug 44340
> (Archived rather fast.)

I have no idea what any of the above means.

What is the bug?

bug#44375: Always give a message when flashing the screen

[積丹尼 Dan Jacobson]

In http://debbugs.gnu.org/cgi/bugreport.cgi?bug=44340 one can see how to
produce a [Show] button.

If the user just clicks it, the screen flashes.

Instead there should be a message printed at the bottom of the screen.

"Don't just click me. I need to be specially clicked: with the middle
button to work."

The above is a case of where flashing should be replaced by a message.

I think most of the cases where emacs just flashes like this, leaving
the user puzzled, have been found already. But there still may be others.

bug#44375: Always give a message when flashing the screen

[Lars Ingebrigtsen]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> In http://debbugs.gnu.org/cgi/bugreport.cgi?bug=44340 one can see how to
> produce a [Show] button.
>
> If the user just clicks it, the screen flashes.

I'm now sure what's this is about.  Clicking any links (with mouse-1) in
the *Help* buffer here dings my Emacs, and this is the backtrace I'm
getting if I instrument `ding':

Debugger entered--entering a function:
* ding()
  pop-mark()
  #f(compiled-function () #<bytecode 0xb41ff211354d205>)()
  #f(compiled-function () #<bytecode 0x1b178ae04d6865b2>)()
  clear-transient-map()

I don't have a recipe to reproduce it, though -- In this Emacs I can do
`M-x describe-face RET default RET' and then mouse-1 on the "faces.el"
button, and Emacs will ding me before taking me to the faces.el file.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#44375: Always give a message when flashing the screen

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> I don't have a recipe to reproduce it, though -- In this Emacs I can do
> `M-x describe-face RET default RET' and then mouse-1 on the "faces.el"
> button, and Emacs will ding me before taking me to the faces.el file.

I still don't have a recipe -- it seems to happen after having done an
unspecified number of actions in the *Help* buffer.  The thing that's
dinging is this, though:

(defun mouse-drag-track (start-event)

[...]

     t (lambda ()
         (setq track-mouse old-track-mouse)
         (setq auto-hscroll-mode auto-hscroll-mode-saved)
         (deactivate-mark)
         (pop-mark)))))

When the pop-mark is called (mark t) is non-nil.  pop-mark is just this:

(defun pop-mark ()
  "Pop off mark ring into the buffer's actual mark.
Does not set point.  Does nothing if mark ring is empty."
  (when mark-ring
    (setq mark-ring (nconc mark-ring (list (copy-marker (mark-marker)))))
    (set-marker (mark-marker) (car mark-ring))
    (set-marker (car mark-ring) nil)
    (unless (mark t) (ding))
    (pop mark-ring))
  (deactivate-mark))

(mark t) is nil here, so it dings.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#44375: Always give a message when flashing the screen

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> (defun pop-mark ()
>   "Pop off mark ring into the buffer's actual mark.
> Does not set point.  Does nothing if mark ring is empty."
>   (when mark-ring
>     (setq mark-ring (nconc mark-ring (list (copy-marker (mark-marker)))))
>     (set-marker (mark-marker) (car mark-ring))

And this is the bit that unsets the mark -- the first entry in mark-ring
is a mark that points to no buffer.

Is it obvious to anybody what's going wrong here?  :-)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#44375: Always give a message when flashing the screen

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Is it obvious to anybody what's going wrong here?  :-)

The `ding' in `pop-mark' has been there since the function was first
written, but there doesn't really seem to be a reason to ding at the
user in this case, so I've removed the ding.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no