The recent version of makepkg introduces some new variables in the PKGBUILD and the possibility to overwrite some of them in additional pacakge_*() functions.

At first those new variables should be recognized bei namcap. The following features might be quite useful:

* check if the pkgname array matches the names of package_* functions and vice versa.
* check if all deps and optdeps introduced in package_* functions are covered by the global makedepends.
** as a bnous: ignore inter-sub-package depends

All those tests can be run on the PKGBUILD; the resulting package does not know about splitting of course. Maybe its a lot easier to implement this in Bash than Python.