Stanislav Brabec wrote:
Such assumption as what the user probably has or has not usage for doesn't belong to low level stuff like a package. A package cannot (and should not) know everything about all the system and the about the user preferences. In this case, what if the user intends to use a mysql on a remote machine?
If mysql client libraries are not installed, (s)he probably don't want.
The plain presence of a package is not an indication. For good results a more advanced heuristic is required, and this is simply not task of a package. The libgda-mysql is nice example how attempts to fine-tune this on an inapropriate level will break. As Reinhard said, the libraries will be present, becouse they are required by zillion another packages.
The package also has many unresolved dependencies, but I really want to suggest here: "Yes, install all these dependencies to have a cool gstreamer package." Whether a package is cool for a user depends on his preferences, something a high level setup tool can know about but a package cannot..
But packager should know, that it is perfectly possible to use libgda without libgda-mysql (only not for MySQL databases), but it is hard to use gstreamer without gstreamer-plugins-extra (because it is not able to play many common audio format). But it is still not hard-dependency, because your music player is still able to play WAV without it.
Perfect reason for a Suggests.
Maybe it should be evident, why package Suggests/Enhances other package, to provide enough information to user. For example:
Package: mc Suggests: (xv eog gv pdftotext)("To provide default viewers. You can define different viewers and ignore these suggestions.")
Package: gnome-session Suggests: gnome2-user-docs("To provide enhanced user documentation.") The purpose should be obvious from the suggested package description.
In other cases it is not obvious, that: "Without package yyy, you will be able to use all tools from xxx except zzz, which is not commonly used."
This, as oposite to attempting to hide the Suggestion, is a valid reason for complex Suggests expressions, to describe that aaa is enhanced by xxx and even more by xxx and yyy but not enhanced by yyy alone. Best Regards, Marian