bug#27040: 25.2: fringe click event bug

bug#27040: 25.2: fringe click event bug

[Charles A. Roelli]

In Emacs 25.1/25.2:

   - emacs -q
   - C-h k
   - Click somewhere in the fringe:

     => Args out of range: "Describe key (or click or menu item): 
mouse-1", 0, 64

Same recipe in Emacs 24.5 pops up a description of the binding as expected:

=========
<mouse-1> (translated from <down-mouse-1> <mouse-1>) at that spot runs
the command mouse-set-point, which is an interactive compiled Lisp
function in `mouse.el'.

It is bound to <triple-mouse-1>, <double-mouse-1>, <mouse-1>.

(mouse-set-point EVENT)

Move point to the position clicked on with the mouse.
This should be bound to a mouse click event type.
=========

As a side note, while you click and hold the mouse in the fringe in an 
emacs-lisp mode
buffer in Emacs 25.2, the echo area indicates the current mode name. 
(This does not
happen in Emacs 24.5).  Not sure if this is related (or intentional).

bug#27040: 25.2: fringe click event bug

[Eli Zaretskii]

> From: "Charles A. Roelli" <charles@aurox.ch>
> Date: Tue, 23 May 2017 20:13:20 +0200
> 
> In Emacs 25.1/25.2:
> 
>    - emacs -q
>    - C-h k
>    - Click somewhere in the fringe:
> 
>      => Args out of range: "Describe key (or click or menu item): 
> mouse-1", 0, 64

Thanks, fixed.

> As a side note, while you click and hold the mouse in the fringe in an 
> emacs-lisp mode
> buffer in Emacs 25.2, the echo area indicates the current mode name. 
> (This does not
> happen in Emacs 24.5).  Not sure if this is related (or intentional).

I have no idea where this comes from.  Looks like some subtle bug.
Please submit a separate bug report.

bug#27040: 25.2: fringe click event bug

[Charles A. Roelli]

On 27/05/2017 15:00, Eli Zaretskii wrote:
>> From: "Charles A. Roelli" <charles@aurox.ch>
>> Date: Tue, 23 May 2017 20:13:20 +0200
>>
>> In Emacs 25.1/25.2:
>>
>>    - emacs -q
>>    - C-h k
>>    - Click somewhere in the fringe:
>>
>>      => Args out of range: "Describe key (or click or menu item):
>> mouse-1", 0, 64
>
> Thanks, fixed.

Thank you.  Can I ask how you found the source of the error?
M-x toggle-debug-on-error doesn't help much in this case.

>
>> As a side note, while you click and hold the mouse in the fringe in an
>> emacs-lisp mode
>> buffer in Emacs 25.2, the echo area indicates the current mode name.
>> (This does not
>> happen in Emacs 24.5).  Not sure if this is related (or intentional).
>
> I have no idea where this comes from.  Looks like some subtle bug.
> Please submit a separate bug report.

Will do.

bug#27040: 25.2: fringe click event bug

[Eli Zaretskii]

> From: "Charles A. Roelli" <charles@aurox.ch>
> Date: Sat, 27 May 2017 15:30:00 +0200
> 
> >>    - emacs -q
> >>    - C-h k
> >>    - Click somewhere in the fringe:
> >>
> >>      => Args out of range: "Describe key (or click or menu item):
> >> mouse-1", 0, 64
> >
> > Thanks, fixed.
> 
> Thank you.  Can I ask how you found the source of the error?

By running Emacs under GDB and setting a C-level breakpoint on the
function 'xsignal', through which all the errors are signaled.  That
showed me that Emacs was calling 'substring' on a string shorter than
the 3rd argument of the function.

bug#27040: 25.2: fringe click event bug

[Charles A. Roelli]

Thanks!  I need to get more familiar with GDB...


On 27/05/2017 15:50, Eli Zaretskii wrote:
>> From: "Charles A. Roelli" <charles@aurox.ch>
>> Date: Sat, 27 May 2017 15:30:00 +0200
>>
>>>>     - emacs -q
>>>>     - C-h k
>>>>     - Click somewhere in the fringe:
>>>>
>>>>       => Args out of range: "Describe key (or click or menu item):
>>>> mouse-1", 0, 64
>>> Thanks, fixed.
>> Thank you.  Can I ask how you found the source of the error?
> By running Emacs under GDB and setting a C-level breakpoint on the
> function 'xsignal', through which all the errors are signaled.  That
> showed me that Emacs was calling 'substring' on a string shorter than
> the 3rd argument of the function.