Message224293
| Author |
vstinner |
| Recipients |
giampaolo.rodola, gvanrossum, pitrou, vstinner, yselivanov, zach.ware |
| Date |
2014年07月30日.10:08:04 |
| SpamBayes Score |
-1.0 |
| Marked as misclassified |
Yes |
| Message-id |
<1406714884.75.0.392365750563.issue22104@psf.upfronthosting.co.za> |
| In-reply-to |
| Content |
> It may be related to the issue #17911.
I checked: it is. The strange reference count can be seen with a single test. Example:
$ ./python -m test -R 3:3: -m test_default_exc_handler_coro test_asyncio
[1/1] test_asyncio
beginning 6 repetitions
123456
......
test_asyncio leaked [53, 53, -106] references, sum=0
test_asyncio leaked [15, 15, -30] memory blocks, sum=0
1 test failed:
test_asyncio
This test uses a coroutine which raises an exception. The exception is stored in a Task object. But the exception contains also a traceback which indirectly creates a reference cycle. For example, the zero_error_coro() coroutine of the test uses the free variable "self".
It's very difficult to find all objects of a reference cycle. We can try to break some cycles, it's already done Task._step() which sets self to None, but it's a waste of time. IMO the correct fix is to not store frame objects in an exception: see the issue #17911. |
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