Bug#980099: virtual packages are failing to resolve when older versions of real packages are present when building buster-backports

It seems node-buble not only build-depends versioned on node-debbundle-acorn but also unversioned on rollup. Since dependency on rollup is unversioned, the package from buster is prioritized over the one from backports, and the one from buster depends unversioned on node-acorn. Seems the

Bug#980099: virtual packages are failing to resolve when older versions of real packages are present when building buster-backports

Package: aspcud,aptitude severity: important When trying to build node-buble (and any other package that build depends on node-acorn provided as a virtual package by node-debbundle-acorn in buster-backports) (I)Distcheck: Cudf Universe: 61258 packages (I)Distcheck: --checkonly specified,