Detailed steps to reproduce the problem?

On PyMongo version 4.15.0 if we use uvloop (the latest version is 0.21.0), we get timeout for any request with asynchronous client.

A minimal code example:

import pymongo, uvloop

async def mongo_info():
    c = pymongo.AsyncMongoClient('mongodb://localhost:27017')
    info = await c.server_info()
    print(info)
 
uvloop.run(mongo_info())

This code does not work with PyMongo 4.15.0 and works fine with PyMongo 4.14.1

Error:

pymongo.errors.ServerSelectionTimeoutError: localhost:27017: timed out (configured timeouts: socketTimeoutMS: 20000.0ms, connectTimeoutMS: 20000.0ms), Timeout: 30s, Topology Description: <TopologyDescription id: 68c2e1984d3d91e9826abd09, topology_type: Unknown, servers: [<ServerDescription ('localhost', 27017) server_type: Unknown, rtt: None, error=NetworkTimeout('localhost:27017: timed out (configured timeouts: socketTimeoutMS: 20000.0ms, connectTimeoutMS: 20000.0ms)')>]> 

Definition of done: what must be done to consider the task complete?

Fix the described problem. PyMongo >=4.15.0 should work correctly with uvloop.

The exact Python version used, with patch level:

3.11.13 (main, Jun  4 2025, 08:57:30) [GCC 13.3.0]

The exact version of PyMongo used, with patch level:

4.15.0

Describe how MongoDB is set up. Local vs Hosted, version, topology, load balanced, etc.

docker/mongo:latest

The operating system and version (e.g. Windows 7, OSX 10.8, ...)

Ubuntu 24.04 WSL2