Yury Selivanov added the comment:
So Ivan made an interesting observation: if we use Python version of
functools.lru_cache, typing tests start to leak like crazy:
beginning 6 repetitions
123456
......
test_typing leaked [24980, 24980, 24980] references, sum=74940
I experimented a bit, and I *think* I know what's happening:
* typing uses an lru cache for types.
* It looks like that some types in the cache are being *reused* by different
tests.
* Because typing doesn't set the size of the lru cache, it's set to 128
(default).
* When many typing tests execute, the cache invalidates some entries, but
because types in test_typing are so complex, I believe that the resulting graph
of objects it too complex for the GC to go through (10s of thousands of
cross-linked objects).
A simple fix that removes fixes the refleak with Python version of lru_cache is
to add a 'tearDown' method to 'test_typing.BaseTestCase':
class BaseTestCase(TestCase):
def tearDown(self):
for f in typing._cleanups:
f()
Now this all of this is just my guess of what's going on here. It might be
something that has to be fixed in typing, or maybe we should just add tearDown.
Guido, Ivan, what do you think?
----------
resolution: fixed ->
status: closed -> open
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue28649>
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