KeyError: <aiohttp.connector._TransportPlaceholder>

[rndusr]

I'm not sure if this is a bug in aiohttp, but if it's a bug in my code, this error doesn't tell my anything:

  File "/home/ich/code/stig/stig/client/aiotransmission/rpc.py", line 328, in __post
    response = await self.__session.post(repr(self.__url), data=data, headers=self.__headers)
  File "/home/ich/code/aiohttp/aiohttp/helpers.py", line 102, in __await__
    ret = yield from self._coro
  File "/home/ich/code/aiohttp/aiohttp/client.py", line 233, in _request
    conn = yield from self._connector.connect(req)
  File "/home/ich/code/aiohttp/aiohttp/connector.py", line 386, in connect
    self._acquired.remove(placeholder)
KeyError: <aiohttp.connector._TransportPlaceholder object at 0x7f270bc78c88>

So, placeholder is added to self._acquired (line 379) and then removed again (line 386), but inbetween it has already been removed, hence the KeyError.

The culprit is self._create_connection(req) (line 382), and eventually self._loop.create_connection() (line 732), and then I'm losing track.

Anyway, a simple if placeholder in self._acquired: inserted in line 386 seems to fix the issue for me. Or it could be something wrong with my code, but then I still have no idea what it is I'm doing wrong. I'd appreciate any pointers what could cause this.

I can reproduce, but unfortunately not with simple, sharable code.

[rndusr]

After some more investigating, I think the issue is that I somehow close() my ClientSession before _create_connection() is finished. close() calls self._acquired.clear() (line 328) and that explains the KeyError when placeholder is to be removed from self._acquired after _create_connection() finished.

I've fixed my code, but it seems to me that this is still an issue in aiohttp. I should either get a more helpful exception or placeholder should be removed with the discard() method, which does nothing if placeholder isn't in self._acquired.

[fafhrd91]

fixed by 941a218

[fafhrd91]

e404760

[lock]

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[new issue]: https://github.com/aio-libs/aiohttp/issues/new