Re: Policy regarding virtual packages

[Russ Allbery <rra@debian.org>]

Magnus Holmgren <holmgren@lysator.liu.se> writes:

> Actually they can, but it's recommended that a real package be given as
> well. From /usr/share/lintian/checks/fields.desc:

> Tag: virtual-package-depends-without-real-package-depends
> Type: warning
> Ref: policy 7.4
> Info: The package declares a depends on a virtual package without listing a
>  real package as an alternative first.
>  .
>  A real package should be listed in the first part of the | dependency in
>  order for the package to be installable by package management programs that
>  can't or won't guess which alternative to select by default. In particular,
>  it helps build daemons rebuild the package without manual overrides.

There's a much better version of this warning in current lintian:

Tag: virtual-package-depends-without-real-package-depends
Type: warning
Info: The package declares a depends on a virtual package without listing a
 real package as an alternative first.
 .
 If this package could ever be a build dependency, it should list a real
 package as the first alternative to any virtual package in its Depends.
 Otherwise, the build daemons will not be able to provide a consistent
 build environment.
 .
 If it will never be a build dependency, this isn't necessary, but you may
 want to consider doing so anyway if there is a real package providing
 that virtual package that most users will want to use.

This is really only an issue with build dependencies.  For regular
dependencies, the only problem is the UI issue of what a package manager
should do when a package depends only on a virtual package, but that's a
solvable UI question.  (For example, one reasonable thing that the package
manager could do is present a list of packages fulfilling that virtual
requirement and ask the user to pick.)

-- 
Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>