Deprecation warning in web_response.py with Python 3.7 #3480
Description
Long story short
When warnings are enabled, a warning like this is printed on importing aiohttp.web with Python 3.7:
/Users/dmajda/tmp/warnings/aiohttp/.venv/lib/python3.7/site-packages/aiohttp/web_response.py:33: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working
BaseClass = collections.MutableMapping
This pullutes the output of our test suite (for which we have warnings enabled).
Expected behaviour
No warning gets printed when importing aiohttp.web.
Actual behaviour
A warning gets printed when importing aiohttp.web.
Steps to reproduce
$ python3 --version
Python 3.7.0
$ python3 -m venv .venv
[...]
$ . .venv/bin/activate
$ pip3 install aiohttp
[...]
$ python3 -Wall -c 'import aiohttp.web'
/Users/dmajda/tmp/warnings/aiohttp/.venv/lib/python3.7/site-packages/aiohttp/web_response.py:33: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working
BaseClass = collections.MutableMappingYour environment
aiohttp version: 3.5.1
Python version: 3.7.0
OS: macOS Mojave