bug#24086: 25.1.50; ibuffer-do-view-1 fails to visit in new frame

[Eli Zaretskii <eliz@gnu.org>]

> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Wed, 27 Jul 2016 20:32:40 +0900 (JST)
> 
> When the argument TYPE is 'other-frame, it should visit
> the buffer in a new frame.

Not unconditionally, though.  There are clearly some conditions in the
code under which the above should not happen.

> emacs -Q --eval="(progn (require 'ibuffer) (setq ibuffer-expert t) (ibuffer))"

Invoking this command, I get an error:

  Wrong type argument: window-live-p, nil

>   (defun ibuffer-do-view-1 (type)
> -  (let ((marked-bufs (ibuffer-get-marked-buffers)))
> +  (let ((marked-bufs (ibuffer-get-marked-buffers))
> +        (confirm t))
>       (when (null marked-bufs)
>         (setq marked-bufs (list (ibuffer-current-buffer t))))
> -    (unless (and (eq type 'other-frame)
> +    (when (and (eq type 'other-frame)
>   		 (not ibuffer-expert)
> -		 (> (length marked-bufs) 3)
> -		 (not (y-or-n-p (format "Really create a new frame for %s 
> buffers? "
> -					(length marked-bufs)))))
> -      (set-buffer-modified-p nil)
> -      (delete-other-windows)
> -      (switch-to-buffer (pop marked-bufs))
> +		 (> (length marked-bufs) 3))
> +      (setq confirm
> +            (y-or-n-p (format "Really create a new frame for %s buffers? 
> "
> +                              (length marked-bufs)))))
> +
> +    (when confirm
> +      (unless (eq type 'other-frame)
> +        (set-buffer-modified-p nil)
> +        (delete-other-windows)
> +        (switch-to-buffer (pop marked-bufs)))
>         (let ((height (/ (1- (if (eq type 'horizontally) (frame-width)
>   			     (frame-height)))
>   		       (1+ (length marked-bufs)))))

Does the change have to be this complicated?  AFAICT, the error is
just in the wrong logic of combining the conditions.  Right?

Thanks.