don't silently discard UDP errors - #1295
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Errors reported by the transport overwrote each other, so a burst of OS errors lost all but the last one. Queue them instead, popping the oldest first, and only restore the write back-pressure once the queue drains. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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A send() cancelled while blocked on the post-send wait leaves its datagram in the asyncio transport's buffer with the protocol still paused. Without a wait before sendto(), the next send() hands its datagram straight to the transport, which appends it to that non-empty buffer without ever trying the OS, so repeated cancellation grows the buffer despite the zero high water mark. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
# Conflicts: # tests/test_sockets.py
error_received() sets the write event while the transport is still paused, so that a sender blocked on it can raise the error. If a concurrent receive() claims that error first, take_exception() re-clears the event, but a sender already released from the pre-send wait didn't re-check: it went on to hand its datagram to a paused transport, which only appends it to its buffer without ever offering it to the OS. Guard the pre-send wait with the same write_paused loop the post-send wait uses, so the pause flag, rather than the event, decides when it's safe to send. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
# Conflicts: # src/anyio/_backends/_asyncio.py
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Unlike Trio, which runs a cancel_shielded_checkpoint() on the way out of a failed socket call, the closed and broken paths now only get the checkpoint_if_cancelled() at the top. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
# Conflicts: # src/anyio/_backends/_asyncio.py
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Changes
Fixed UDP sockets on the asyncio backend silently discarding errors reported by the OS (such as an ICMP port unreachable). A task blocked in
receive()orsend()is now woken up by such an error, and both raiseBrokenResourceError, chained to the original error, as they already did on the Trio backend. As on the Trio backend, the error is only reported once, leaving the socket usable afterwardsChecklist
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