Re: rpm gets some deps wrong?

[James Olin Oden <joden malachi lee k12 nc us>]

On Wed, 6 Aug 2003, Jeff Johnson wrote:

> Frank Cusack wrote:
> 
> >On Mon, Aug 04, 2003 at 08:42:33AM -0400, Jeff Johnson wrote:
> >  
> >
> >>Frank Cusack wrote:
> >>
> >>    
> >>
> >>>I don't understand why rpm is complaining about breaking a dependency,
> >>>when the package being removed doesn't provide said dependency:
> >>>
> >>>[root@mother root]# rpm -e kernel-smp-2.4.21-gg3
> >>>error: Failed dependencies:
> >>>	kernel-smp = 2.4.21-gg2 is needed by (installed) NVIDIA_kernel-2.4.21-gg2-smp-1.0-4363gg10
> >>>	kernel-smp = 2.4.21-gg2 is needed by (installed) bcm5700-2.4.21-gg2-smp-6.2.11-gg3
> >>>
> >>>      
> >>>
> 
> You have 2 packages with a dependency on the package that you are
> upgrading. The dependency specifies a version, but not an epoch.
> Missing epoch is equivalent to Epoch:0 when packages are installed.
> 
> (Note: "when installed" missing epoch == 0, now everywhere.)
> 
> Both packages have the same version, but not the same epoch. So the new
> does not satisfy the previously satisifed  dependency because it has an 
> epoch.
> 
> Even though the versions are the same, the epoch's are not.
>
The thing you have to realize, Frank, is when dependencies are compared 
rpm looks at not just the version (%version), but it looks at what I call
the fully qualified version (no originality, I know), which is made up of
three components:

	Epoch(E)
	Version(V)
	Release(R)

Thinking of each one as seperate digits for the sake of comparison, rpm 
does the following comparison:

	EVR1 (operator) EVR2

So Epoch is most significant, Version is next in significance, and Release 
is last.  It would be simular to comparing 110 to 210.  Yes the 10's 
places are equal, but the 100's are not; just as in your case the Versions 
are equal but the Epochs are not, and Epochs win.

Cheers...james