nbio: fix op re-use

core/nbio/impl_posix.odin

@@ -1154,6 +1154,8 @@ stat_exec :: proc(op: ^Operation) {
 
 add_pending :: proc(op: ^Operation, filter: kq.Filter, ident: uintptr) {
 	debug("adding pending", op.type)
+	op._impl.next = nil
+	op._impl.prev = nil
 	op._impl.flags += {.For_Kernel}
 
 	_, val, just_inserted, err := map_entry(&op.l.submitted, Queue_Identifier{ ident = ident, filter = filter })

tests/core/nbio/nbio.odin

@@ -256,3 +256,78 @@ wake_up :: proc(t: ^testing.T) {
 		}
 	}
 }
+
+@(test)
+reused_ops :: proc(t: ^testing.T) {
+	if event_loop_guard(t) {
+		testing.set_fail_timeout(t, time.Minute)
+
+		@static payload := [4]byte{'P', 'I', 'N', 'G'}
+		sock, ep := open_next_available_local_port(t)
+
+		State :: struct {
+			listener:      nbio.TCP_Socket,
+			accepts:       [4]^nbio.Operation,
+			client:        nbio.TCP_Socket,
+			server_client: nbio.TCP_Socket,
+			recv_buf:      [4]byte,
+			recv_done:     bool,
+		}
+
+		state := State{
+			listener = sock,
+		}
+
+		on_accept :: proc(op: ^nbio.Operation, t: ^testing.T, state: ^State, slot: int) {
+			if state.recv_done {
+				nbio.close(op.accept.client)
+				return
+			}
+
+			ev(t, op.accept.err, nil)
+			if state.server_client == 0 {
+				state.server_client = op.accept.client
+				nbio.recv_poly2(state.server_client, {state.recv_buf[:]}, t, state, on_recv, timeout=0)
+			}
+
+			state.accepts[slot] = nbio.accept_poly3(op.accept.socket, t, state, slot, on_accept, timeout=nbio.NO_TIMEOUT)
+		}
+
+		on_recv :: proc(op: ^nbio.Operation, t: ^testing.T, state: ^State) {
+			ev(t, op.recv.err, nil)
+			ev(t, op.recv.received, 4)
+			ev(t, state.recv_buf, payload)
+			state.recv_done = true
+
+			for accept in state.accepts {
+				if accept != nil {
+					nbio.remove(accept)
+				}
+			}
+
+			nbio.close(state.server_client)
+			nbio.close(state.client)
+			nbio.close(state.listener)
+		}
+
+		on_dial :: proc(op: ^nbio.Operation, t: ^testing.T, state: ^State) {
+			ev(t, op.dial.err, nil)
+			state.client = op.dial.socket
+			nbio.send_poly2(state.client, {payload[:]}, t, state, on_send)
+		}
+
+		on_send :: proc(op: ^nbio.Operation, t: ^testing.T, state: ^State) {
+			ev(t, op.send.err, nil)
+			ev(t, op.send.sent, (4))
+		}
+
+		for slot in 0 ..< 4 {
+			state.accepts[slot] = nbio.accept_poly3(sock, t, &state, slot, on_accept, timeout=nbio.NO_TIMEOUT)
+		}
+		ev(t, nbio.tick(0), nil)
+
+		nbio.dial_poly2(ep, t, &state, on_dial)
+		ev(t, nbio.run(), nil)
+		e(t, state.recv_done)
+ 	}
+ }