Re: apt-get's choice of a dependent package

[Remco van de Meent <remco@dnd.utwente.nl>]

Peter S Galbraith wrote:
> 
> It would be nice if apt had some way of knowing which package is
> preferred to fulfill a dependency.

It has. When you specify multiple packages with a boolean OR, the first one
is preferred ("Depends: tk8.2 | tk8.0" would lead to tk8.2 if neither of
them is installed).

> For example, the package august depends on `wish'.
> `wish' is really anything in:
> 
>   tk8.0-ja or tk4.2 or tkstep8.0 or tkstep4.2 or tk8.0 or tk8.2

The 'problem' with wish is that it's a virtual package. Hence, the first
package providing this virtual package is chosen to install.

$ apt-cache depends august
august
  Depends: <wish>
    tkstep8.0
    tkstep4.2
    tk8.2
    tk8.0-ja
    tk8.0
    tk4.2

==> tkstep8.0 

This package needs tcl8.0 (among others), so that one gets selected as well.

> I'm happy it didn't try to automatically install a more esoteric provider
> of wish, but I suppose it's possible.

It won't install a more esoteric provider of wish because the dependencies
are fulfilled.  If ``august'' needs a specific version, it should mention
that in its dependencies.


		Remco