I’ve just spent a little time squashing several bugs on the trot, all the same: insufficient build-dependencies when built in a clean environment. Typically this means that the package was uploaded after being built on a developer’s normal machine, which already has everything required installed.
It’s long been the case that we have several ways to build packages in a clean chroot before upload, which reveals these sorts of errors and more. There’s not really any excuse for uploading packages that fail to build in this way.
Please, for the sanity of everyone working with the archive, don’t upload packages that haven’t been built in a clean environment. It’s such a waste of everybody’s time if you don’t do this most basic of checks.