Deprecation warnings in asyncio with Python 3.8

[dmajda]

• asyncpg version: 0.19.0
• PostgreSQL version: N/A
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: N/A
• Python version: 3.8.0
• Platform: N/A
• Do you use pgbouncer?: no
• Did you install asyncpg with pip?: yes
• If you built asyncpg locally, which version of Cython did you use?: N/A
• Can the issue be reproduced under both asyncio and
  uvloop?: N/A

When using asyncpg with Python 3.8 with warnings enabled, deprecation warnings are emitted at various places where a loop argument is passed to asyncio APIs. This is because explicit passing of that argument was deprecated and will be removed in Python 3.10.

A test suite of one of our internal services that uses asyncpg detected the following instances, but there can be more:

• connect_utils.py line 515
• connect_utils.py line 530
• connect_utils.py line 537

It would be good to fix these warnings. I’m not sure whether it would involve just refactoring few asyncio API calls, or whether it would require deeper changes in loop handling inside the library.

[1st1]

Fixed in #504

[1st1]

Thanks for reporting!