Fails to parse virtual package providers from oneiric's apt

I ran into this problem on https://launchpad.net/ubuntu/+source/kde4libs/4:4.7.0-0ubuntu1 since it build-depends on libjpeg-dev, which is a virtual package. What's really odd though is that after i386, amd64, and armel had hit depwait due to this bug, I uploaded ubuntu2 to build-dep on the real package. Then powerpc and armel (which had previously depwait) built. See (note: build was manually killed by lamot):

https://launchpad.net/ubuntu/+source/kde4libs/4:4.7.0-0ubuntu1/+build/2650993

lamot/lamont

This appears to be an issue with apt (or something even lower level), not sbuild. One can witness with a simple "apt-get install mail-transport-agent" followed by "apt-get install mail-transport-agent > foo" that the package list, while happily displayed on your console, isn't making it to STDOUT pipes, which sbuild needs to read them.

What's much more distressing is that strace shows the list being written to FD 1 (which vaguely matches with "hey, we can see it on the console"), so I have no idea why neither Perl nor the shell redirect get around to seeing it.

This bug was fixed in the package apt - 0.8.16~exp5ubuntu8

---------------
apt (0.8.16~exp5ubuntu8) oneiric; urgency=low

  * cherry pick r1825 from lp:~mvo/apt/mvo:
    * apt-pkg/contrib/configuration.cc:
    - fix double delete (LP: #848907)
    - ignore only the invalid regexp instead of all options

  * cherry pick r2165 from lp:~donkult/apt/sid:
    [ David Kalnischkies ]
    * cmdline/apt-get.cc:
      - output list of virtual package providers to c1out in -q=1
        instead of /dev/null to unbreak sbuild (LP: #816155)
 -- Michael Vogt <email address hidden> Tue, 13 Sep 2011 18:23:09 +0200