So the key point here is to be able to check in advance whether a build would fail and at a minimum report “You need X, Y and Z, please install them before proceeding” or for more capable installers (essentially ones that are capable of installing non-Python dependencies) actually install the dependencies and then proceed to the build?
That would be great, and I’d be very much in favour of it - even for pip, having better errors and not starting builds that are guaranteed to fail would be a great step forward.
Excuse my ignorance here, but I assume the first thing we’d need is some means of naming such dependencies in a platform and installer independent way? Is that correct? For example, “g++” isn’t a very good name for a dependency on a C++ compiler for a Windows user, who would typically be using Visual C++. Is that the sort of thing that you’d expect to cover in the PEP?