Value yielded by PoolAcquireContext is mistyped by IDEs

• asyncpg version: 0.21.0
• PostgreSQL version: 12.5
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: No
• Python version: 3.9.1
• Platform: Windows 10
• 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

Using PyCharm Professional 2020.2 by JetBrains, the typing of conn is interpreted incorrectly in the following expression:

pool = await asyncpg.create_pool('postgres://...')
async with pool.acquire() as conn:
    await conn.execute(...)

Expected: asyncpg.Connection
Observed: typing.Any
Suggested remedy: Explicitly type PoolAcquireContext.connection as typing.Optional[Connection] and/or explicitly type PoolAcquireContext.pool as Pool.
Caveat: The suggestions above will break compatibility with Python 3.4, which reached end of life in March 2019.

Commencez par les définitions de type de PoolAcquireContext et reproduisez l’exemple pool.acquire() dans PyCharm afin d’inspecter le type inféré de conn. Comparez les annotations de connection et pool avec le type asyncpg.Connection attendu indiqué, tout en vérifiant la réserve de compatibilité avec Python 3.4. Le travail est terminé lorsque l’IDE infère correctement conn sans supprimer la compatibilité prise en charge.