[Quinnod345]

AnyIO v1 catches the stdlib incomplete-read exception, but its stream raises the package exception. Asyncio v2 has the reverse mismatch. A peer closing during negotiation therefore bypasses the intended ProxyError conversion.

Catch each stream's actual EOF type. Keep AnyIO's existing shielded cleanup behavior when moving EOF into its specific handler. The regression uses the public proxy APIs with both AnyIO backends and asyncio v2. It covers truncated replies, protocol errors, successful tunnels and cancellation.

Local validation against upstream 8d054e5855e354735b95f2004d9fe8242920e261:

• The same final regression has 14 failures and 12 passing controls on upstream. Correcting only the exception imports leaves 2 close-cancellation failures and 24 passes. The complete fix passes all 26 cases.
• All 429 project tests pass on macOS with CPython 3.14.7, AnyIO 4.16.0 and Trio 0.35.0. That run used owned loopback fixtures with ephemeral ports and runtime URL data.
• Ruff and formatting pass. Focused Mypy passes 60 files. Full Mypy reports three errors in unchanged test helpers; pristine upstream has the same diagnostics in this environment.

Other Python versions, operating systems and hosted CI were not run locally. The close-cancellation regression uses an owned asynchronous test stream; it does not demonstrate a native transport leak.

I maintain Ponder. Its review flagged the mismatched EOF handlers and helped check cleanup preservation. I implemented the patch and ran the checks above.

[romis2012]

In asyncio v2 we should handle python_socks._errors.IncompleteReadError (not asyncio.IncompleteReadError) for consistency.
At the same time we should catch asyncio.IncompleteReadError and raise python_socks._errors.IncompleteReadError in python_socks.async_.asyncio.v2._stream.AsyncioSocketStream.read_exactly