pkgutil.get_loader calls
pkgutil.find_loader which calls
importlib.find_loader

The latter logs a deprecation warning about it being replaced by importlib.util.find_spec.

This is a regression in 3.4 as far as I can see.

This also happens with the latest hg version.  I could not make an isolated test case unfortunately but it happens on the flask testsuite if run on 3.4.

Ah, I think I see what may have happened - when we finally switched all the stdlib importers over to PEP 302 (and consistently set __loader__), the pkgutil.get_loader fallback to pkgutil.find_loader stopped being exercised by the test suite (it's currently missing lower level unit tests), and so we missed that it was still calling a deprecated API. (And we don't currently have any CI set up to warn us when coverage of a module goes backwards)

I'll add some new tests to get coverage and change it to use importlib.util.find_spec instead.

Attached patch adds some appropriate unit tests, switches pkgutil.find_loader over to using importlib.util.find_spec and updates the docs appropriately.

I also filed issue 20842 relating to the fact that the pkgutil docs still refer to PEP 302 when they should be referring to the glossary terms instead.

Brett, Eric - if this looks right to you, feel free to commit and create the issue for Larry to incorporate it into 3.4.0.

LGTM, but I won't be able to commit it until Friday so hopefully Eric or you can do it sooner.

OK, I can add it tonight.

New changeset ea827c809765 by Nick Coghlan in branch 'default':
Close #20839: pkgutil.find_loader now uses importlib.util.find_spec
http://hg.python.org/cpython/rev/ea827c809765

New changeset a8b30fd6ee4f by Nick Coghlan in branch '3.4':
Close #20839: pkgutil.find_loader now uses importlib.util.find_spec
http://hg.python.org/cpython/rev/a8b30fd6ee4f