Re: defcustom :version

[Luc Teirlinck]

Note that there is a bug in the current implementation of the :version
keyword.  For instance, `M-x customize-changed' lists the group
gnus-agent as new in Emacs 22.1 whereas it was already present in
Emacs 20.7 and possibly earlier.  The problem is that the :version for
`foo' gets stored in the custom-version property of the symbol 'foo.
But `foo' could be two or three of a customizable variable, a custom
group and a face.  All three could have been introduced in different
versions.  One of those could be new in a new release, the others not.
Only that one should be listed by `customize-changed'.  But depending
on luck, either none or all get listed, because only one of the three
:version's winds up being the lucky winner of the "symbol foo
custom-version property contest".

In the case of gnus-agent, the group is not new in 22.1, but the
variable gnus-agent is.

Maybe we should have {option,face,group}-custom-version properties,
maybe after the release.

Sincerely,

Luc.