demandimport: fix compatibility with meta path finders w/o find_spec() method...
demandimport: fix compatibility with meta path finders w/o find_spec() method
Meta path finders got a find_spec() method in Python version 3.4. The
sys.meta_path documentation says that the deprecated find_module() method is
used as a fallback.
Setuptool’s VendorImporter still doesn’t have the find_spec() method,
which resulted in a crash e.g. within a virtual environment. For reference, I
opened an issue for that:
https://github.com/pypa/setuptools/issues/2104.
An alternative implementation would have been to implement a wrapper for
find_module() itself and raise an AttributeError when accessing find_spec() if
the wrapped finder doesn’t have it.
