Panic when receiving a reset on a stream in the process of closing #246
Description
This is the cause of upstream issue linkerd/linkerd2#607.
It appears that when a stream is in the process of transitioning from Half-Closed (remote) to Closed, with a Trailers frame queued to end that stream, and a Reset (Canceled) frame is received, h2 will hit an expect in prioritize.rs and panic.
Here's the expect that fails:
https://github.com/carllerche/h2/blob/f8baeb7211985834acaf7ecc70548aafd5d9ef6d/src/proto/streams/prioritize.rs#L693-L694
And the relevant logs from @bourquep's panicking Conduit instance:
E TRCE h2::proto::streams::state send_close: HalfClosedRemote => Closed
E TRCE h2::proto::streams::send send_trailers -- queuing; frame=Headers { stream_id: StreamId(107), stream_dep: None, flags: HeadersFlag { end_stream: true, end_headers: true, padded: false, priority: false } }
E TRCE h2::proto::streams::prioritize schedule_send; StreamId(107)
E TRCE h2::proto::streams::store Queue::push
E TRCE h2::proto::streams::store -> first entry
E TRCE h2::proto::streams::prioritize reserve_capacity; stream=StreamId(107); requested=0; effective=0; curr=0
E TRCE h2::proto::settings send_pending_ack; pending=None
E TRCE h2::codec::framed_read poll
E TRCE h2::codec::framed_read poll; bytes=13B
E TRCE h2::codec::framed_read decoding frame from 13B
E TRCE h2::codec::framed_read -> kind=Reset
E DBUG h2::codec::framed_read received; frame=Frame::Reset(Reset { stream_id: StreamId(107), error_code: CANCEL })
E TRCE h2::proto::connection recv RST_STREAM; frame=Reset { stream_id: StreamId(107), error_code: CANCEL }
E TRCE h2::proto::streams::prioritize clear_queue; stream-id=StreamId(107)
E TRCE h2::proto::streams::prioritize dropping; frame=Frame::Headers(Headers { stream_id: StreamId(107), stream_dep: None, flags: HeadersFlag { end_stream: true, end_headers: true, padded: false, priority: false } })
E TRCE h2::proto::settings send_pending_ack; pending=None
E TRCE h2::codec::framed_read poll
E TRCE h2::proto::streams::prioritize try reclaim frame
E TRCE h2::proto::streams::prioritize poll_complete
E TRCE h2::proto::streams::prioritize schedule_pending_open
E TRCE h2::proto::streams::prioritize pop_frame
E TRCE h2::proto::streams::prioritize pop_frame; stream=StreamId(107)
E thread 'main' panicked at 'must be scheduled to reset', /checkout/src/libcore/option.rs:891:5
E note: Run with `RUST_BACKTRACE=1` for a backtrace.More information on the specific case where this issue occurs may be found in linkerd/linkerd2#607.