svn+ssh://pythondev@svn.python.org/python/branches/py3k
........
r74584 | brett.cannon | 2009-08-29 20:47:36 -0700 (Sat, 29 Aug 2009) | 3 lines
Have importlib raise ImportError if None is found in sys.modules. This matches
current import semantics.
........
and relies much more on meta path finders to abstract out various parts of
import.
As part of this the semantics for import_module tightened up and now follow
__import__ much more closely (biggest thing is that the 'package' argument must
now already be imported, else a SystemError is raised).