* Because ``None`` is now inserted into :attr:`sys.path_importer_cache`, if you
are clearing out entries in the dictionary of paths that do not have a
finder, you will need to remove keys paired with values of ``None`` **and**
- :class:`imp.NullImporter` to be backwards-compatible. This will need to extra
+ :class:`imp.NullImporter` to be backwards-compatible. This will lead to extra
overhead on older versions of Python that re-insert ``None`` into
:attr:`sys.path_importer_cache` where it repesents the use of implicit
finders, but semantically it should not change anything.
both the modification time and size of the source file the bytecode file was
compiled from.
+* :func:`pkgutil.iter_modules` and :func:`pkgutil.walk_packages` no longer work
+ with modules imported using the default import system. Both functions have
+ always relied on a non-standard method (``iter_modules()``) to be defined on
+ loaders to work and the import system now always provides a loader for
+ modules but does not implement the non-standard method.
+
Porting C code
--------------