> From: Bob Weiner <rsw@gnu.org>
> Date: Sat, 16 Feb 2019 17:08:47 -0500
>
> With point on a "Choose" button in a customize-group buffer, point is on
> a text-property button and (button-at (point)) returns a marker object
> rather than a button whose action is a marker object. Thus, if one
> calls (push-button) at that location, it sends this marker object as the
> button argument to 'button-activate' which then triggers an error when
> it tries to funcall the button's action which is nil in this case.
> Shouldn't there be additional logic that checks if the button itself is
> a marker and then uses the button as the action in that case?
>
> Related to this: (button-type (button-at (point))) returns nil which seems
> to contradict the fact that button-at returns non-nil.
>
> Am I missing things here or does button-activate need additional code?
button-activate and push-button already include that additional code,
but you are trying to invoke them on a kind of "button" that they
don't know how to handle. The problem is that "button" is overloaded
here: buttons created by Customize are not of the kind supported by
functions from button.el, you need to invoke functions described in
widget.info instead. The "text-property buttons" mentioned in the
documentation of button-at etc. are those created by make-text-button
and insert-text-button, not those created by Customize.
I really don't fully understand what you are saying here.
There is a section in
widget.info which describes use of the (push-button)
function which is defined in button.el, so although I
understand you are saying there are two different types
of buttons, it seems like they are connected. Maybe
the custom widgets use text-property buttons.
If you could, for each of the two types of buttons,
just show code that finds the button at point and then
activates it, so I can see the difference clearly. That
would be most helpful.
And what about (button-type (button-at (point))) returning
nil when button-at returns non-nil. Both of these functions
operate on push-buttons as the button.el code reflects, right?
If so, then that should be a bug. If not, then it could use
some explanation.
Thanks,
Bob