invisible spec in elide-head

[Matthias Meulien <orontee@club.lemonde.fr>]

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In GNU Emacs 21.2.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2002-06-28 on clarinde
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: fr_FR.ISO-8859-15
  value of $LC_CTYPE: fr_FR.ISO-8859-15
  value of $LC_MESSAGES: en_US
  value of $LC_MONETARY: fr_FR.ISO-8859-15
  value of $LC_NUMERIC: fr_FR.ISO-8859-15
  value of $LC_TIME: fr_FR.ISO-8859-15
  value of $LANG: fr
  locale-coding-system: iso-latin-9
  default-enable-multibyte-characters: t

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

Look at the way the header is made invisible in `elide-head':

(overlay-put elide-head-overlay 'invisible t)

Now suppose you call `elide-head' in a buffer in `outline-mode';
`outline-mode' had add (outline . t) to `buffer-invisibility-spec',
which made `buffer-invisibility-spec' into a list. But

,----[ C-h v buffer-invisibility-spec RET ]
| (...)
| This variable is always local in all buffers.
| The default is t, which means that text is invisible
| if it has a non-nil `invisible' property.
| If the value is a list, a text character is invisible if its `invisible'
| property is an element in that list.
| If an element is a cons cell of the form (PROP . ELLIPSIS),
| then characters with property value PROP are invisible,
| and they have an ellipsis as well if ELLIPSIS is non-nil.
`----

The header will not disappear because the `invisible' property of the
elide-head-overlay isn't an element of `buffer-invisibility-spec' !

Recent input:
<switch-frame> <f6> <down> <down> <return> <down> <down> 
<down> <down> <down> <down> <down> <down> <return> 
<return> <left> <right> <left> <M-left> <M-right> <down> 
<down> <return> <down> <return> C-x 5 2 <switch-frame> 
M-x r e p o <tab> r SPC e m <tab> <return>

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-- 
Matthias