set-frame-height glitch [Was: Re: Changes in frame/window code]

[Dmitry Antipov <dmantipov@yandex.ru>]

On 07/23/2014 04:48 PM, martin rudalics wrote:

> With emacs -Q and an internal tool bar evaluate one after the other
>
> (frame-height)
> (set-frame-height nil (1+ (frame-height)))
> (frame-height)
>
> Here the `set-frame-height' shrinks the frame.

Nice shot.  But, IIUC, this means that set-frame-height goes wrong
but should be:

=== modified file 'src/frame.c'
--- src/frame.c	2014-07-21 16:58:12 +0000
+++ src/frame.c	2014-07-23 15:01:44 +0000
@@ -2584,8 +2584,11 @@
      {
        if (NILP (pixelwise))
  	{
-	  if (XINT (height) != FRAME_LINES (f))
-	    x_set_window_size (f, 1, FRAME_COLS (f), XINT (height), 0);
+	  int actual = FRAME_LINES (f) - FRAME_TOP_MARGIN (f);
+	  int requested = XINT (height) + FRAME_TOP_MARGIN (f);
+
+	  if (requested != actual)
+	    x_set_window_size (f, 1, FRAME_COLS (f), requested, 0);

  	  do_pending_window_change (0);
  	}

Dmitry