Is yum dependency resolution upside down?

[Michael Schwendt]

On Mon, 13 Jun 2011 12:55:02 +0800, KP wrote:

> I don't know if it is yum, the package group definitions or the package
> dependencies that are wrong - but no matter who is to blame - the result is
> definitely not intuitive (or imho correct)...

You read the dependencies backwards.

> Below are a few examples:
> 
> # yum -C groupremove "Dial-up Networking Support"
> 
> Is removing "ppp" - and NetworkManager for dependencies:
> ----------------------
> Removing:
>  ppp                    i686 2.4.5-12.fc14  @updates                      752 k
> Removing for dependencies:
>  NetworkManager         i686 1:0.8.4-1.fc14 @updates                      5.5 M
>  NetworkManager-gnome   i686 1:0.8.4-1.fc14 @updates                      1.5 M
>  NetworkManager-openvpn i686 1:0.8.1-1.fc14 @anaconda-InstallationRepo-201010211
>  NetworkManager-vpnc    i686 1:0.8.1-1.fc14 @anaconda-InstallationRepo-201010211
> ----------------------
> 
> NetworkManager is part of (installed) "System Tools" group - not dial-up modem
> so why does it even consider to remove it?

Notice the "Removing" and "Removing for dependencies" headers.
If you remove ppp, you cannot keep any packages that depend on ppp.
Your option in such a scenario is to remove leaf packages only, or to
erase individual packages (with either Yum or RPM).

$ repoquery --whatrequires ppp
ppp-0:2.4.5-17.fc15.x86_64
NetworkManager-1:0.8.999-2.git20110509.fc15.x86_64
NetworkManager-1:0.8.9997-2.git20110531.fc15.x86_64
NetworkManager-pptp-1:0.8.999-1.fc15.x86_64
bluemodem-0:0.7-6.fc15.x86_64
kdenetwork-7:4.6.2-2.fc15.x86_64
kdenetwork-7:4.6.3-1.fc15.x86_64
ppp-0:2.4.5-17.fc15.x86_64
pptp-0:1.7.2-12.fc15.x86_64
rp-pppoe-0:3.10-8.fc15.x86_64
synce-serial-0:0.11-5.fc15.x86_64
wvdial-0:1.61-4.fc15.x86_64
xfce4-modemlights-plugin-0:0.1.3.99-7.fc15.x86_64
xl2tpd-0:1.2.7-3.fc15.x86_64

For your other non-detailed examples, one would need to look at the
details (= the dependencies) to understand why something would be removed.