[mayankdhingra02]

Cancellation or a timeout while establishing an asyncio/Trio TCP connection bypasses the existing OSError cleanup, leaving the newly allocated socket open. A failed local-address bind has the same ownership gap.

Keep socket setup, binding and connection establishment inside the cleanup guard, close on any unsuccessful exit, and re-raise the original exception. Successfully returned sockets remain open for the caller. The stream-based v2 and AnyIO helpers are unchanged.

Validation on macOS:

• Eight regression/control cases: six fail on the original implementation; all eight pass with the fix. They cover cancellation, timeout, binding failures and usable successful connections.
• An actual loopback Proxy.connect() task cancellation, without socket/loop mocks, leaves an open descriptor on the original code and a closed descriptor with the fix.
• Full suites pass on Python 3.9, 3.10, 3.11, 3.12, 3.13, 3.14 and free-threaded 3.14: 403 tests per runtime, including sync, asyncio, Trio, AnyIO and v2 APIs. Ruff checks/formatting and mypy pass on all seven runtimes.
• The four asyncio cases also pass with optional Trio absent. Wheel and source distribution builds pass.

Linux and Windows remain for CI.

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.31%. Comparing base (1427381) to head (9807fa6).
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Additional details and impacted files

@@            Coverage Diff             @@
##           master      #51      +/-   ##
==========================================
- Coverage   94.36%   94.31%   -0.05%     
==========================================
  Files          55       55              
  Lines        1562     1566       +4     
==========================================
+ Hits         1474     1477       +3     
- Misses         88       89       +1     

Flag	Coverage Δ
unit	94.31% <100.00%> (-0.05%)	⬇️

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