Re: Documentation for custom-file - is not (load custom-file) needed?

[Luc Teirlinck]

Richard Stallman wrote:
   
   A small amount of incompatibility in something unusual and advanced
   like this is no big deal.

If I understand your proposal correctly, if the user has a non-nil
custom file, nothing changes compared to 21.3.  The file will no
longer be automatically loaded after .emacs as in current CVS, but
that did not happen in 21.3 anyway.

So the only problem concerns the case where custom-file is nil.

If custom-file is nil, the user currently expects Custom to write
exclusively into .emacs.  All current packages the user is using
expect that.

Here is a very concrete example where your proposed change could cause
trouble.  From initsplit.el (not included with the Emacs distribution
but used by some people):

;; Note that that you *must* load each file that contains your various
;; customizations from your .emacs.  Otherwise, the variables won't
;; all be set, and the next time you use the customize interface, it
;; will delete the settings in those other files.

You are going to save in the last of those files, which are written in
some random order.  If I understand correctly, with custom-file being
nil, initsplit is watching .emacs for customizations being written in
there, to delete them from .emacs and put them in the correct
(according to the user) files.

Even if by some miracle your proposed changes would not break initsplit,
they are likely to break other similar packages.

Second scenario where your changes could cause trouble:

The user may load several files with `custom-set-variables' forms to
add a set of customizations to his .emacs.  Then he just nominally
saves some option using Custom to make Custom write all the stuff into
.emacs.  So you save everything in the last file he loaded.  I hope he
notices before he deletes that file.  I also hope that he does not use
that file for other purposes.

I understand the reasons for no longer automatically loading
custom-file after .emacs.  I understand the reasons for removing the
defcustom.  I do not understand what problems would remain after that.

Sincerely,

Luc.