Redisplay inf-loop with (recenter -1)

[lawrence mitchell]

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

In some cases, when Emacs is displaying glyphs that are higher
than the line-height, adding (recenter -1) to
window-scroll-functions causes Emacs to enter an infinite loop.

A simple test case:

$ emacs -q --no-site-file --eval '(blink-cursor-mode -1)'

C-h h (view the HELLO file)

Scroll to the bottom of the window.

(add-hook 'window-scroll-functions
          (lambda (&rest ignore)
             (recenter -1)))

Scroll down again, Emacs gets into an infinite loop which may be
broken out of with C-g.

In GNU Emacs 21.3.50.9 (i686-pc-linux-gnu, GTK+ Version 2.2.4)
 of 2004-01-17 on yam
configured using `configure '--prefix=/opt/sw/emacs-21.3.5/'
'--with-gtk' '--with-xpm' '--with-jpeg' '--with-tiff'
'--with-gif' '--with-png' '--without-xim' '--without-sound'
'--without-pop' '--with-kerberos' '--with-kerberos5''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: C
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: C
  value of $LC_TIME: C
  value of $LANG: en_GB
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t


-- 
lawrence mitchell <address@hidden>