[pypy-issue] Issue #2649: recvmsg with empty err queue raises odd OSError rather than BlockingError (pypy/pypy)

[chrysn]

New issue 2649: recvmsg with empty err queue raises odd OSError rather than BlockingError
https://bitbucket.org/pypy/pypy/issues/2649/recvmsg-with-empty-err-queue-raises-odd

chrysn:

pypy3 nightly builds behave different from cpython3.5 in that a recvmsg(..., MSG_ERRQUEUE) on a socket that has no queued errors raises BlockingError in cpython, but raises "OSError: received malformed or improperly truncated ancillary data" .

Please consider changing the behavior to match the one of cpython, which looks like the correct behavior to me.

The attached script can be used to show the difference.

Thank you for your work on pypy!