Re: dpkg seems not to 'see' virtual package installed.

[Prekates Alexandros <aprekates@gmail.com>]

στις 13/12/2010 02:04 πμ, O/H Jonathan Nieder έγραψε:
> Hi Alex,
>
> Prekates Alexandros wrote:
>
>   
>> cnijfilter-common depends from libcupsys2 (>= 1.2.1). But:
>> Package libcupsys2 in not installed
>>     
> The meaning of dependencies is spelled out in full in the Debian
> policy manual (which is the closest we have to a high-level manual for
> dpkg).  It says[1]:
>
> 	If a relationship field has a version number attached, only
> 	real packages will be considered to see whether the
> 	relationship is satisfied 
>
> The code agrees[2].
>
>       /* If there was no version specified we try looking for Providers. */
>       if (possi->verrel == dvr_none) {
>
> I believe it would be possible to diagnose this better, though ---
> for example: in addition to
>
> 	 cnijfilter-common depends on libcupsys2 (>= 1.2.1)
> 	  libcupsys2 is not installed but configs remain
>
> to say something like
>
> 	  libcup2 provides libcupsys2, but virtual packages have no version
>
> If you would like to work on that, I'd be glad ot provide any help
> I can.
>
> Regards,
> Jonathan
>
> [1] http://www.debian.org/doc/debian-policy/ch-relationships.html#s-virtual
> [2] src/depcon.c::depisok
>   


Thanks very much for the explanation.

So for time being cancelling packages and making them virtual (like
libcupsys2) is an operation that could break dependencies to thirdparty
packages.

I'll try to look at it as soon as i find some time.