Is yum dependency resolution upside down?

[Michael Schwendt]

On Mon, 13 Jun 2011 17:48:12 +0800, KP wrote:

> On Mon, Jun 13, 2011 at 4:31 PM, Michael Schwendt wrote:
> >
> > You read the dependencies backwards.
> [...]
> > If you remove ppp, you cannot keep any packages that depend on ppp.
> 
> Remember that what I wanted was to remove "Dial-up Networking Support" - it is
> not expected that this operation should remove all Networking!

Then what is it supposed to do instead?

"yum groupinfo 'Dial-up Networking Support'" tells that "ppp" is a
Mandatory Package in that group. If you wanted to remove ppp, you would
need to remove everything that requires ppp. Do you understand that?
If so, you can tell Yum to exit its confirmation check by answering "no".

> Just as when I tried to remove "Electronic Lab" - it is not expected that this
> operation should remove eclipse, fonts and screensavers, right?

Not right. At least the font packages you've mentioned are part of
that group:

$ yum groupinfo 'Electronic Lab'|grep font
   xorg-x11-fonts-100dpi
   xorg-x11-fonts-ISO8859-1-100dpi
   xorg-x11-fonts-ISO8859-9-100dpi
   xorg-x11-fonts-Type1

Same for several eclipse packages, which probably are required by
eclipse and hence can only be removed if eclipse gets removed as well:

$ yum groupinfo 'Electronic Lab'|grep ecli
   eclipse-cdt
   eclipse-dltk-tcl
   eclipse-eclox
   eclipse-epic
   eclipse-subclipse
   eclipse-texlipse
   eclipse-veditor

> I am pretty sure I had fonts and screensavers before I installed "drawtiming"
> and "openocd". Do you see what I mean?

Not yet. Have you read the "man yum" section about "groupremove" and
"remove" yet?

Both commands are not the exact opposite of "groupinstall" and "install" due
to dependencies on additional packages. A groupinstall can add required packages
not listed in the group. Same for a normal install. "yum install foo" may pull
in packages that would not be removed by "yum remove foo". A groupremove tries
to remove all packages listed in the group plus anything that depends on them,
which can be packages listed also in other groups.