This code was an artifact of issuing a DeprecationWarning for the lack
of loader.exec_module(). However, we have deferred such warnings to
later Python versions.
Early in the PEP 451 implementation some of the importlib loaders had
their own _get_spec() methods to simplify accommodating them. However,
later implementations removed the need. They simply failed to remove
this code at the same time. :)
module loaders.
Due to the fact that the call signatures for extension modules and
built-in modules does not allow for the specifying of what module to
initialize and that on Windows all extension modules are built-in
modules, work to clean up built-in and extension module initialization
will have to wait until Python 3.5. Because of this the semantics of
exec_module() would be incorrect, so removing the methods for now is
the best option; load_module() is still used as a fallback by
importlib and so this won't affect semantics.
importlib.machinery.FileFinder.
While originally moved to stop special-casing '' as PathFinder farther
up the typical call chain now uses the cwd in the instance of '', it
was deemed an unnecessary risk to breaking subclasses of FileFinder to
take the special-casing out.
exists when checking for a package.
Before there was an isdir check and then various isfile checks for
possible __init__ files when looking for a package.
This change drops the isdir check by leaning
on the assumption that a directory will not contain something named
after the module being imported which is not a directory. If the module
is a package then it saves a stat call. If there is nothing in the
directory with the potential package name it also saves a stat call.
Only if there is something in the directory named the same thing as
the potential package will the number of stat calls increase
(due to more wasteful __init__ checks).
Semantically there is no change as the isdir check moved
down so that namespace packages continue to have no chance of
accidentally collecting non-existent directories.
