Error in ClientSession __del__

[sk-]

The __del__ method of ClientSession available for Python >= 3.4.1 produces inconsistent tracebacks.
I'm using Aiohttp 0.17.3 on Mac Os X Yosemite, with Python 3.4.3.

With the same code I've seen the following ones:
(Note: this same code was working fine with aiohttp 0.16.5 and it also works if I just comment out https://github.com/KeepSafe/aiohttp/blob/b6bfb7afbe1b786ca396757c5a88c3822fc4057a/aiohttp/client.py#L79-L90)

Exception ignored in: <bound method ClientSession.__del__ of <aiohttp.client.ClientSession object at 0x101975b70>>
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/aiohttp/client.py", line 77, in __del__
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/aiohttp/client.py", line 342, in close
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/aiohttp/connector.py", line 235, in close
TypeError: 'NoneType' object is not callable

Exception ignored in: <bound method ClientSession.__del__ of <aiohttp.client.ClientSession object at 0x102075b70>>
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/aiohttp/client.py", line 79, in __del__
AttributeError: 'NoneType' object has no attribute 'warn'

Exception ignored in: <bound method ClientSession.__del__ of <aiohttp.client.ClientSession object at 0x102175b70>>
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/aiohttp/client.py", line 80, in __del__
TypeError: 'NoneType' object is not callable

Exception ignored in: <bound method ClientSession.__del__ of <aiohttp.client.ClientSession object at 0x102175b70>>
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/aiohttp/client.py", line 85, in __del__
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py", line 1036, in call_exception_handler
AttributeError: 'NoneType' object has no attribute 'error'

[asvetlov]

Thanks for report. It should be fixed in both aiohttp and asyncio.

[asvetlov]

This is only partial fix: the same should be done for asyncio for logger instance.

Let's leave the issue open until making asyncio fix.

[asvetlov]

@sk for sake of best practice please don't rely on garbage collector but explicitly call session.close() after finishing all jobs for the session.

[sk-]

@asvetlov: Thanks for pointing out that I should close the session. I was using it in a command line crawler, and the program was terminating after completing the jobs. Closing the session fixes my problem.