So this is bringing up a sticky situation that I ran across when initially implementing all of this: what should sys.path_importer_cache use as a key? '' would be what happens with Madison's option 3, and with option 1 it would be os.getcwd(). Now if you iterate through sys.path you won't find what '' connects to. Then again, it won't be accurate if you change the directory either.

So the question becomes should sys.path_importer_cache reflect exactly what is in sys.path or what should be cached for a finder based on what import should do (i.e. the full path and change based on the cwd)?