does it also build at buildd after a source only upload.
At the official build machines it is n't allowed to install a package
which isn't called in debian/control beside the essential build packages.
You have to call *all needed* packages for building in debian/control.
Otherwise it can't be build at the official build machines.
This should be ensured by pbuilder. You have to be able to build in a
clean pbuilder chroot.
indeed, and we all agree on that.
I'm using sbuild in a clean sid chroot, and i don't see the problem with sphinx at all.
Could the problem be somewhere else ?