bug#45737: 27.1.50; Assertion failure in window_box_height

[martin rudalics <rudalics@gmx.at>]

 >> That would be better indeed.  But I suppose this would require to
 >> implement zero-height windows, something you didn't like when we
 >> discussed it about a year ago.
 >
 > Can you help me understand why this would mean zero-height windows?
 > What I had in mind was to constraint resizing so that the min-window
 > is always at least 1-line high.

It depends on what you have in mind with "constraint resizing".

- We can constraint the frame size via size hints so a user can never
   make the frame smaller than needed to make all its windows visible.
   Whether this works with other window managers depends to be seen, is
   not general practice with practically all other applications I know of
   and, as mentioned before, doesn't really work on Windows.  And we
   would have to make it optional to avoid offending any users.

- Otherwise we'd have to constraint the size of normal windows since
   'window-safe-min-height' gives them always at least one frame line and
   if a frame contains two windows above each other and shrinks to two
   lines, these lines will be filled up already.  So the display engine
   and/or the windows code would have to "skip" these windows to allow
   showing the minibuffer window instead.  For me skipping a window is
   tantamount to giving it "zero height".

But maybe I'm missing something.

martin