Comment 2 for bug 900081

A "complete apt line in quotes" requires a type at the beginning, (deb, deb-src, rpm, or rpm-src). If you add "deb " to your example, it will work as you expect. Without a type, it matches this argument type: "a repo url and areas in quotes (areas defaults to 'main')" so oneiric-proposed is assumed to be an area.