bug#3600: 23.0.94; shrink-window-if-larger-than-buffer

[martin rudalics]

> The code imposes this as one of the conditions for fitting the window
> to the buffer:
>
> (or (not (frame-parameter frame 'minibuffer))
>     (let ((mini-window (minibuffer-window frame)))
>       (or (null mini-window)
>           (not (eq frame (window-frame mini-window)))
>                (< (nth 3 edges) (nth 1 (window-edges mini-window)))
>                (> (nth 1 edges) (frame-parameter frame 'menu-bar-lines)))))
>
> I don't understand the last condition (>). At the least, this
> condition seems to be missing from the doc string:
>
> "Do nothing if the buffer contains more lines than the present window
> height, or if some of the window's contents are scrolled out of view,
> or if shrinking this window would also shrink another window, or if
> the window is the only window of its frame."
>
> What is that last condition (>) for?  What is the relation between the
> number of menu-bar-lines and the `Top' position of the window?

I guess it's a poor man's attempt to make sure that there's some other
window above or below the one to shrink.

> And doesn't this code raise an error if the `menu-bar-lines' parameter
> is nil? Should it really be doing that?

Looks like a bug.  Could you try the attached patch?  Since this code
hasn't been touched for quite some time we can't fix it for Emacs 23.1
though.

martin

*** window.el.~1.180.~  2009-05-07 11:10:52.000000000 +0200
--- window.el   2009-06-18 11:31:13.234375000 +0200
***************
*** 1520,1527 ****
    (when (null window)
      (setq window (selected-window)))
    (let* ((frame (window-frame window))
!        (mini (frame-parameter frame 'minibuffer))
!        (edges (window-edges window)))
      (if (and (not (eq window (frame-root-window frame)))
             (window-safely-shrinkable-p window)
             (pos-visible-in-window-p (point-min) window)
--- 1520,1526 ----
    (when (null window)
      (setq window (selected-window)))
    (let* ((frame (window-frame window))
!        (mini (frame-parameter frame 'minibuffer)))
      (if (and (not (eq window (frame-root-window frame)))
             (window-safely-shrinkable-p window)
             (pos-visible-in-window-p (point-min) window)
***************
*** 1530,1539 ****
                 (let ((mini-window (minibuffer-window frame)))
                   (or (null mini-window)
                       (not (eq frame (window-frame mini-window)))
!                      (< (nth 3 edges)
!                         (nth 1 (window-edges mini-window)))
!                      (> (nth 1 edges)
!                         (frame-parameter frame 'menu-bar-lines))))))
        (fit-window-to-buffer window (window-height window)))))
  
  (defun kill-buffer-and-window ()
--- 1529,1536 ----
                 (let ((mini-window (minibuffer-window frame)))
                   (or (null mini-window)
                       (not (eq frame (window-frame mini-window)))
!                      (/= (window-height window)
!                          (window-height (frame-root-window frame)))))))
        (fit-window-to-buffer window (window-height window)))))
  
  (defun kill-buffer-and-window ()