[NoahStapp]

PYTHON-6200 follow-up

Changes in this PR

Reset monitor pools to prevent a race between the executor being stopped and the monitor being closed.

Test Plan

Existing test suite.

Checklist

Checklist for Author

• Did you update the changelog (if necessary)?
• Is there test coverage?
• Is any followup work tracked in a JIRA ticket? If so, add link(s).

Checklist for Reviewer

• Does the title of the PR reference a JIRA Ticket?
• Do you fully understand the implementation? (Would you be comfortable explaining how this code works to someone else?)
• Is all relevant documentation (README or docstring) updated?

[Copilot]

🟡 Changes recommended

A deterministic regression test is still needed for the shutdown race in both Monitor and _RttMonitor, since the existing test can pass without exercising the problematic interleaving.

1 open issue

• Add deterministic shutdown race regression tests · New

What changed in this PR

This PR addresses PYTHON-6200 by adding monitor-pool cleanup when an executor stops, preventing connections from surviving a shutdown race.

Changes:

• Reset the main monitor’s connections during final cleanup.
• Reset the round-trip-time monitor’s pool when its executor stops.
• Mirror the asynchronous changes in the generated synchronous implementation.

File	Description
pymongo/​synchronous/​monitor.py	Mirrors the shutdown cleanup in synchronous monitors.
pymongo/​asynchronous/​monitor.py	Adds final pool resets to both asynchronous monitor types.

_{Review effort: Balanced}