I meant to suggest that your patch (based on agwego's recommendation) should be accepted. Now that you ask, I'm not so sure anymore: errors should never pass silently.

So I now think, that it should raise IncompleteRead, based also on the observation that these methods can *already* raise IncompleteRead, and that this already carries the data that we received.

OTOH, IIUC, the error also means that we lost protocol synchronisation with the server, so we should in any case close the connection. So merging these changes is probably the right thing :-) Withdrawing my acceptance again, and hoping that somebody can produce a complete patch (which includes the test case in a style that works with regrtest)