bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

[Kevin Ryde]

While nosing around the unload-feature stuff I wondered if
unload-feature-special-hooks should include fill-nobreak-predicate, as
it's a hook now.

The damage from leaving an unloaded func there is limited to paragraph
filling, and is likely to be either buffer local, or be autoloaded and
then end up ok anyway.  You can see a bad effect currently for instance
with

    M-x sgml-mode
    M-x unload-feature sgml-mode
    type in a long line to be filled
    M-q
    => Symbol's function definition is void: sgml-fill-nobreak


In GNU Emacs 23.1.1 (i486-pc-linux-gnu, GTK+ Version 2.16.5)
 of 2009-09-14 on raven, modified by Debian
configured using `configure  '--build=i486-linux-gnu' '--host=i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.1/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.1/leim' '--with-x=yes' '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars' 'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''

bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

[Juanma Barranquero]

On Wed, Jan 6, 2010 at 00:38, Kevin Ryde <user42@zip.com.au> wrote:

> While nosing around the unload-feature stuff I wondered if
> unload-feature-special-hooks should include fill-nobreak-predicate, as
> it's a hook now.

It's a hook or hook-like, and its name does not end in -hooks?, so yes.

As an aside, perhaps unload-feature should also remove automatically
unloaded funcs from symbols called *-functions, which would eliminate
much cruft from `unload-feature-special-hooks'. The question is
whether there are many variables called -functions which are not
really hooks.

    Juanma

bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

[Kevin Ryde]

Juanma Barranquero <lekktu@gmail.com> writes:
>
> The question is
> whether there are many variables called -functions which are not
> really hooks.

That'd be the dangerous bit.  I've got a defconst called -functions in
some of my code, but it wouldn't be hurt.

Those with a custom-type of 'hook or '(repeat function) could be likely.
In fact any var with that custom-type might be ok to act on.  A grep
finds me three called -functions (code below)

    find-directory-functions
    auto-coding-functions
    compile-command-default-functions

of which auto-coding-functions may be the only important one not
presently in unload-feature-special-hooks.




(pp (let (ret)
      (mapatoms (lambda (sym)
                  (and (boundp sym)
                       (get sym 'custom-type)
                       (not (memq sym unload-feature-special-hooks))
                       (string-match "-functions\\'" (symbol-name sym))
                       (push (list sym (get sym 'custom-type)) ret))))
      ret)
    (current-buffer))

bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

[Juanma Barranquero]

On Wed, Jan 6, 2010 at 00:38, Kevin Ryde <user42@zip.com.au> wrote:

>    M-x sgml-mode
>    M-x unload-feature sgml-mode
>    type in a long line to be filled
>    M-q
>    => Symbol's function definition is void: sgml-fill-nobreak

`fill-nobreak-predicate' was set locally, so it would be removed when
the mode for the buffer was changed. Previously, `unload-feature'
failed to do so unless the mode package's FEATURE-unload-function,
assuming one existed, did by itself. Since revno:104702
`unload-feature' does so automatically, so the above case should work
(i.e, unloading sgml-mode will change the buffer's major mode to
text-mode).

That said, I'll add that variable and some of the others you mentioned
to `unload-feature-special-hooks' because it's better to be safe than
sorry. But, what would be nice is some way to identify hook variables
in a generic way, instead of special-casing still more of them. :-(

>   find-directory-functions
>   auto-coding-functions

OK.

>   compile-command-default-functions

I cannot find that one in the Emacs sources.

    Juanma

bug#5327: 23.1; unload-feature-special-hooks add fill-nobreak-predicate

[Kevin Ryde]

Juanma Barranquero <lekktu@gmail.com> writes:
>
>>   compile-command-default-functions
>
> I cannot find that one in the Emacs sources.

Ah yes, sorry, that's one of my own slipped through.
(Which I jigged up to add to unload-feature-special-hooks too anyway.)


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