Advice requested with tricky dependencies in records.deb

[Tommi Virtanen <tv@debian.org>]

	My package "records" is a nice emacsy way to handle notes and
	such.

	It depends on emacsen, perl5, and mailcrypt. Except that
	XEmacs bundles mailcrypt, so it depends on

        perl5 AND (
                ((emacs20 OR emacs21 OR mule2) AND mailcrypt)
                OR (xemacs21 OR xemacs21-gtk)
        )

	Eww. And it was worse before I noticed most XEmacsen provide
	xemacs21, and GNU Emacsen provide emacsNN or mule2. To ease
	parsing, read that as

        perl5 AND (
                ($GNU_Emacs AND mailcrypt) 
                OR $XEmacs
        )

	This is just something the dependency system can't express. 
	The current package approximates that with

Depends: emacs20 | emacsen, mailcrypt|xemacs20|xemacs21, perl5

        which fails in one case: user has GNU Emacs _and_ XEmacs
        installed, but mailcrypt is not installed. Package
        installation is aborted when it tries to compile the .el for
        GNU Emacs. This is reported as grave bug #84789.

        Suggestions so far:

        1. Make XEmacs provide mailcrypt

                Won't work, XEmacs has mailcrypt in
                /usr/share/xemacs21/packages/lisp/mailcrypt - it is
                meant for XEmacs only. And the lisp might even be
                modified to be specific to XEmacs. GNU Emacs can't
                use that.

        2. Add install-time logic that detects the failing case,
           outputs better information, and fails.

                Doesn't really solve the problem..

        3. Split the package, records-gnuemacs and records-xemacs

                records-gnuemacs would have
		Depends: emacs20 | emacs21 | mule2, mailcrypt, perl5

                records-xemacs would have
		Depends: xemacs21 | xemacs21-gtk, perl5

		This is doable, but a bit ugly. And it means I have
                to enumerate all emacsen -- thankfully not individual
                package names, but only on a higher level.




	Now, I need your $0.02:


        1. Is there any other solution?


        2. If I split the package, should I do

Package: records-gnuemacs
Depends: emacs20 | emacs21 | mule2, mailcrypt, perl5, records-common

Package: records-xemacs
Depends: xemacs21 | xemacs21-gtk, perl5, records-common

Package: records-common

	where records-common has all the real stuff, and the two
	specific packages are just to work around the problems? Or
	should I just include the files in both of the packages? If I
	use a -common, I need to careful not to try to compile the
	.el's for any other emacs than what have records-foo packages
	installed..

-- 
tv@{{hq.yok.utu,havoc,gaeshido}.fi,{debian,wanderer}.org,stonesoft.com}
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