The following code leaks one reference on Python 3.6:

    def test_attributes(self):
        d = dict((entry.name, entry) for entry in os.scandir('.'))

Or try the command:

   ./python -m test -R 3:3 test_os -v -m test_attributes

The owning of references in the path_t structure was changed in issue29034, but some code still directly manipulates reference counters of path_t fields. Proposed patch should fix the leak.

3.7 doesn't leak, but contains outdated comment and code.

3.6 LGTM. 3.7 is technically right to me. But it looks to me AC shouldn't call path_cleanup in .c.h. It always do nothing.

If PyObject_New(ScandirIterator, &ScandirIteratorType) fails the path should be cleaned up by Argument Clinic.

scandir-refleak-3.6.patch LGTM. The following removed Py_CLEAR() is just redundant, so it's ok to remove it.

-    Py_CLEAR(iterator->path.object);

> If PyObject_New(ScandirIterator, &ScandirIteratorType) fails the path should be cleaned up by Argument Clinic.

Ohh yes. My stupid. Then both LGTM.

New changeset 4e3a16bdadae by Serhiy Storchaka in branch '3.6':
Issue #29513: Fixed a reference leak in os.scandir() added in issue #29034.
https://hg.python.org/cpython/rev/4e3a16bdadae

New changeset a3f8c5d172b4 by Serhiy Storchaka in branch 'default':
Issue #29513: Fix outdated comment and remove redundand code is os.scandir().
https://hg.python.org/cpython/rev/a3f8c5d172b4

New changeset be85fd4ef41979dbe68262938da12328fb6cfb8c by Serhiy Storchaka in branch '3.6':
Issue #29513: Fixed a reference leak in os.scandir() added in issue #29034.
https://github.com/python/cpython/commit/be85fd4ef41979dbe68262938da12328fb6cfb8c

Thanks for the quick fix Serhiy! I was working on patch and I like to check
for refleaks. Sadly, it wasn't noticed before. At least my test was pass :-)