Re: address@hidden: window-min-height not obeying its documentation in Emacs 22.1]

[martin rudalics]

> Fixed in HEAD.

The fix is correct but it only cures a symptom of the bug.  The real
problem is what the OP described as

>> You will now see a window that is 1 line tall and is missing its
>> mode line.

That's what you also get when - with `window-min-height' set to 1 - you
split windows or drag the mode-line: The last visible line of the window
whose height becomes 1 reappears as "header-line" of the window below.
Note that here's no convenient safe minimum window height (or width)
since you always have to cater for mode- and header-lines, fringes, and
scroll-bars.  Hence I'd propose something like the attached patch.

*** window.c.~1.577.~   Tue Jun  5 22:41:24 2007
--- window.c    Mon Jul  9 19:29:14 2007
***************
*** 62,67 ****
--- 62,68 ----
  static void window_scroll_pixel_based P_ ((Lisp_Object, int, int, int));
  static void window_scroll_line_based P_ ((Lisp_Object, int, int, int));
  static int window_min_size_1 P_ ((struct window *, int));
+ static int window_min_size_2 P_ ((struct window *, int));
  static int window_min_size P_ ((struct window *, int, int, int *));
  static void size_window P_ ((Lisp_Object, int, int, int, int, int));
  static int freeze_window_start P_ ((struct window *, void *));
***************
*** 2553,2559 ****
      *cols = MIN_SAFE_WINDOW_WIDTH;
  }
  
- 
  /* Value is non-zero if window W is fixed-size.  WIDTH_P non-zero means
     check if W's width can be changed, otherwise check W's height.
     CHECK_SIBLINGS_P non-zero means check resizablity of WINDOW's
--- 2554,2559 ----
***************
*** 2655,2660 ****
--- 2655,2686 ----
    return fixed_p;
  }
  
+ /* Return the minimum size for leaf window W.  WIDTH_P non-zero means
+    take into account fringes and the scrollbar of W.  WIDTH_P zero
+    means take into account mode-line and header-line of W.  Return 1
+    for the minibuffer.  */
+ 
+ static int
+ window_min_size_2 (w, width_p)
+      struct window *w;
+      int width_p;
+ {
+   int size;
+   
+   if (width_p)
+     size = max (window_min_width,
+               (MIN_SAFE_WINDOW_WIDTH
+                + WINDOW_FRINGE_COLS (w)
+                + WINDOW_SCROLL_BAR_COLS (w)));
+   else if (MINI_WINDOW_P (w))
+     size = 1;
+   else
+     size = max (window_min_height,
+               (MIN_SAFE_WINDOW_HEIGHT
+                + (WINDOW_WANTS_MODELINE_P (w) ? 1 : 0)
+                + (WINDOW_WANTS_HEADER_LINE_P (w) ? 1 : 0 )));
+   return size;
+ }
  
  /* Return the minimum size of window W, not taking fixed-width windows
     into account.  WIDTH_P non-zero means return the minimum width,
***************
*** 2724,2745 ****
        }
      }
    else
!     {
!       if (width_p)
!       size = max (window_min_width,
!                   (MIN_SAFE_WINDOW_WIDTH
!                    + WINDOW_FRINGE_COLS (w)
!                    + WINDOW_SCROLL_BAR_COLS (w)));
!       else
!       {
!         if (MINI_WINDOW_P (w)
!             || (!WINDOW_WANTS_MODELINE_P (w)
!                 && !WINDOW_WANTS_HEADER_LINE_P (w)))
!           size = 1;
!         else
!           size = window_min_height;
!       }
!     }
  
    return size;
  }
--- 2750,2756 ----
        }
      }
    else
!     size = window_min_size_2 (w, width_p);
  
    return size;
  }
***************
*** 2981,2991 ****
    Lisp_Object child, *forward, *sideward;
    int old_size, min_size, safe_min_size;
  
-   /* We test nodelete_p != 2 and nodelete_p != 1 below, so it
-      seems like it's too soon to do this here.  ++KFS.  */
-   if (nodelete_p == 2)
-     nodelete_p = 0;
- 
    check_min_window_sizes ();
    size = max (0, size);
  
--- 2992,2997 ----
***************
*** 2996,3017 ****
      {
        old_size = WINDOW_TOTAL_COLS (w);
        min_size = window_min_width;
!       /* Ensure that there is room for the scroll bar and fringes!
!          We may reduce display margins though.  */
!       safe_min_size = (MIN_SAFE_WINDOW_WIDTH
!                      + WINDOW_FRINGE_COLS (w)
!                      + WINDOW_SCROLL_BAR_COLS (w));
      }
    else
      {
        old_size = XINT (w->total_lines);
        min_size = window_min_height;
!       safe_min_size = MIN_SAFE_WINDOW_HEIGHT;
      }
  
    if (old_size < min_size && nodelete_p != 2)
      w->too_small_ok = Qt;
  
    /* Maybe delete WINDOW if it's too small.  */
    if (nodelete_p != 1 && !NILP (w->parent))
      {
--- 3002,3024 ----
      {
        old_size = WINDOW_TOTAL_COLS (w);
        min_size = window_min_width;
!       safe_min_size = window_min_size_2 (w, 1);
      }
    else
      {
        old_size = XINT (w->total_lines);
        min_size = window_min_height;
!       safe_min_size = window_min_size_2 (w, 0);
      }
  
    if (old_size < min_size && nodelete_p != 2)
      w->too_small_ok = Qt;
  
+   /* Move the following test here since otherwise the
+      preceding test doesn't make sense.  martin. */
+   if (nodelete_p == 2)
+     nodelete_p = 0;
+ 
    /* Maybe delete WINDOW if it's too small.  */
    if (nodelete_p != 1 && !NILP (w->parent))
      {
***************
*** 3751,3757 ****
              && ! FRAME_NO_SPLIT_P (XFRAME (XWINDOW (window)->frame))
              && (EQ (window, selected_window)
                  || EQ (XWINDOW (window)->parent, Qnil))
!             && window_height (window) >= window_min_height << 1)
            window = Fsplit_window (window, Qnil, Qnil);
          else
            window = Fget_lru_window (frames, Qnil);
--- 3758,3765 ----
              && ! FRAME_NO_SPLIT_P (XFRAME (XWINDOW (window)->frame))
              && (EQ (window, selected_window)
                  || EQ (XWINDOW (window)->parent, Qnil))
!             && (window_height (window) >=
!                 window_min_size_2 (XWINDOW (window), 0) << 1))
            window = Fsplit_window (window, Qnil, Qnil);
          else
            window = Fget_lru_window (frames, Qnil);
***************
*** 4000,4008 ****
  
    if (NILP (horflag))
      {
!       if (size_int < window_min_height)
        error ("Window height %d too small (after splitting)", size_int);
!       if (size_int + window_min_height > XFASTINT (o->total_lines))
        error ("Window height %d too small (after splitting)",
               XFASTINT (o->total_lines) - size_int);
        if (NILP (o->parent)
--- 4008,4018 ----
  
    if (NILP (horflag))
      {
!       int window_safe_height = window_min_size_2 (o, 0);
!       
!       if (size_int < window_safe_height)
        error ("Window height %d too small (after splitting)", size_int);
!       if (size_int + window_safe_height > XFASTINT (o->total_lines))
        error ("Window height %d too small (after splitting)",
               XFASTINT (o->total_lines) - size_int);
        if (NILP (o->parent)
***************
*** 4015,4024 ****
      }
    else
      {
!       if (size_int < window_min_width)
        error ("Window width %d too small (after splitting)", size_int);
! 
!       if (size_int + window_min_width > XFASTINT (o->total_cols))
        error ("Window width %d too small (after splitting)",
               XFASTINT (o->total_cols) - size_int);
        if (NILP (o->parent)
--- 4025,4035 ----
      }
    else
      {
!       int window_safe_width = window_min_size_2 (o, 1);
!       
!       if (size_int < window_safe_width)
        error ("Window width %d too small (after splitting)", size_int);
!       if (size_int + window_safe_width > XFASTINT (o->total_cols))
        error ("Window width %d too small (after splitting)",
               XFASTINT (o->total_cols) - size_int);
        if (NILP (o->parent)
***************
*** 4499,4505 ****
  
        /* Don't make this window too small.  */
        if (XINT (CURSIZE (window)) + delta
!         < (horiz_flag ? window_min_width : window_min_height))
        {
          Fset_window_configuration (old_config);
          error ("Cannot adjust window size as specified");
--- 4510,4516 ----
  
        /* Don't make this window too small.  */
        if (XINT (CURSIZE (window)) + delta
!         < window_min_size_2 (XWINDOW (window), horiz_flag))
        {
          Fset_window_configuration (old_config);
          error ("Cannot adjust window size as specified");