[ikalchev]

Follow-up to the #544 review: a per-connection write response could outlive its connection.

The deferred cleanup in connection_lost pops a connection's write responses once. A coroutine setter that finished later stored its response again, via setdefault, and nothing removed it: the entry stayed under the closed connection's address forever, where a later connection that reuses the address read it. A Setup Endpoints answer carries its session's SRTP keys, so it must not outlive the connection that wrote.

• The driver registers each controller write with pending coroutine setters in _pending_connection_writes, and connection_lost marks those writes dead.
• _async_finish_set_characteristics drops the responses of dead writes and unregisters them, whatever a setter returns. A response is answered once, to the writing connection, so one that answers after the close would never be read anyway.

The existing test covered a completion that was already queued when the connection closed; the new tests cover a setter finishing after the deferred cleanup ran, for both a wr write response and a read_back_response characteristic. Both fail without the fix. The guard is per pending batch, so nothing accumulates for dead connections.

This PR was made with LLM (GLM-5.3). Verifications mine.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.00%. Comparing base (f7406d3) to head (ea15d57).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev     #557   +/-   ##
=======================================
  Coverage   91.99%   92.00%           
=======================================
  Files          50       50           
  Lines       10822    10839   +17     
  Branches     1402     1404    +2     
=======================================
+ Hits         9956     9972   +16     
  Misses        579      579           
- Partials      287      288    +1     

Files with missing lines	Coverage Δ
pyhap/accessory_driver.py	94.12% <100.00%> (+0.14%)	⬆️

... and 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.