bug#9639: 24.0.90; Problem with bury-buffer in minibuffer-hide-completions

[Stephen Berman]

On Sat, 01 Oct 2011 11:08:09 +0200 martin rudalics <rudalics@gmx.at> wrote:

>> 1. emacs -Q
>> 2. Type `M-x glo TAB' and at the completion "M-x global-" type TAB again,
>>    making a *Completions* buffer pop up.
>> 3. Type `v TAB', yielding the completion "M-x global-visual-line-mode".
>> => The window that had been displaying the *Completions* buffer now
>> displays the *Messages* buffer.
>>
>> AFAICT this is due to the following cond clause in bury-buffer (which is
>> called by minibuffer-hide-completions):
>>
>>      ((not (window-dedicated-p))
>>       (switch-to-prev-buffer nil 'bury))
>
> ... plus the fact that switching buffers should not delete windows ...
>
>> Only after typing RET in the minibuffer to accept the completion is the
>> window that had been displaying the *Completions* buffer and now
>> displays the *Messages* buffer deleted; in Emacs 23.2 it is deleted as
>> soon as the sole completion is displayed in the minibuffer.  Commenting
>> out the above clause restores the 23.2 behavior.  But this presumably
>> has bad effects elsewhere.
>
> Presumably `minibuffer-hide-completions' should iconify a standalone
> completions frame while deleting a split-off completions window.  So
> maybe the following DTRT:
>
> (defun minibuffer-hide-completions ()
>   "Get rid of an out-of-date *Completions* buffer."
>   ;; FIXME: We could/should use minibuffer-scroll-window here, but it
>   ;; can also point to the minibuffer-parent-window, so it's a bit tricky.
>   (let* ((window (get-buffer-window "*Completions*" 0))
>        (buffer (window-buffer window)))
>     (when window
>       (let ((deletable (window-deletable-p window)))
>       (cond
>        ((eq deletable 'frame)
>         ;; Iconify frame.
>         (iconify-frame (window-frame window))
>         (bury-buffer-internal buffer))
>        (deletable
>         ;; Delete window
>         (delete-window window)
>         (bury-buffer-internal buffer))
>        (t
>         ;; Switch to another buffer.
>         (switch-to-prev-buffer window 'bury)))))))

I confirm this DTRT for my case.

Steve Berman