python_set_active_version() and python_pkg_setup() can be used in some ebuilds. When both of them are used, then python_set_active_version() should be called before python_pkg_setup(). repoman should detect ebuilds, which call python_pkg_setup() before python_set_active_version(), and print error.
No activity in 4.5yr, Gentoo is not interested in python.eclass anymore. If you want to do it for progress, I guess you don't need a bug :).