Re: About the 'minibuffer' frame parameter

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 09 Aug 2016 18:07:58 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: emacs-devel@gnu.org
> 
>  >> (1) Make sure that store_frame_param doesn't store invalid parameter
>  >>       values.
>  >>
>  >> (2) Never store a minibuffer window as frame parameter.
>  >>
>  >> (3) Have ‘frame-parameter’ return the 'minibuffer' parameter as stored
>  >>       internally.  If no stored value is available, return t.
>  >>
>  >> (4) Wait for regression reports.
>  >>
>  >> (5) Fix the documentation.
>  >>
>  >> (6) Fix/remove related comments.
>  >
>  > I'm okay with that, but I'm surprised by (2): won't storing the
>  > minibuffer window there allow us to report the correct value in (3)?
>  > What am I missing?
> 
> If we did that we would invert the values returned by ‘frame-parameter’
> for the "normal" frame and minibuffer-less frame cases.  Currently, we
> return the minibuffer window for a normal frame and nil for a
> minibuffer-less frame.  You would return the minibuffer window for a
> minibuffer-less frame and t for a normal frame.  Correct?

Maybe.  Another alternative would be to return a window in both cases.

> This would have the benefit that after
> 
>    (set-frame-parameter minibuffer-less-frame 'minibuffer some-minibuffer-window)
> 
> the value returned by ‘frame-parameter’ would be consistent with the
> requested value.  However, most minibuffer-less frames are created via
> 
>    (make-frame '((minibuffer . nil)))
> 
> and whatever we do here we would introduce another inconsistency: Either
> the stored value is the minibuffer window chosen by Emacs and the value
> returned by ‘frame-parameter’ would not be the value from the PARAMETERS
> argument of ‘make-frame’.  Or we would sometimes return nil and
> sometimes a window as value of the 'minibuffer' frame parameter of a
> minibuffer-less frame.

We have already a few cases where frame-parameter returns a value
different from the one specified when make-frame was called.  There's
nothing wrong about that, if it's Emacs that chooses the actual value.

> Given the fact that changing the frame parameter of a minibuffer-less
> frame is a pretty rare operation, I would prefer the solution sketched
> in (2).  WDYT?

Do you still prefer (2)?  I prefer storing a window because then we
could naturally return it, like we do with frame colors.