add-hook sets hook globally if buffer-local hook is nil

[Alan Shutko]

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

emacs -q --no-site-file

Evaluate this:

(add-hook 'local-write-file-hooks 'beep)

Global value of local-write-file-hooks contains beep!  

This started, I think, with the last change to add-hook.  

In GNU Emacs 21.3.50.13 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2003-10-21 on wesley.springies.com
configured using `configure  'CFLAGS=-g -O3''

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

Major mode: Summary

Minor modes in effect:
  gnus-mailing-list-mode: t
  display-time-mode: t
  auto-compression-mode: t
  auto-image-file-mode: t
  iswitchb-mode: t
  show-paren-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-decoding-mode: t
  unify-8859-on-encoding-mode: t
  column-number-mode: t
  line-number-mode: t

Recent input:
O A ESC O A ESC O A ESC O B ESC O B ESC O B ESC O B 
ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC 
O B ESC O B ESC O B ESC O B ESC O B ESC O B ESC O B 
ESC O B ESC O B ESC O B 1 0 0 SPC C-c C-s C-d ESC [ 
4 ~ C-r h o o k ESC [ 4 ~ M-x r e p o r t - e m TAB 
RET

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-- 
Alan Shutko <address@hidden> - I am the rocks.
5 days, 16 hours, 48 minutes, 38 seconds till closing!
Heaven don't want me, & hell's afraid I'll take over.