Bugfix async demotion

The 'releaseOutboundConnection' is moved following peer status
update to PeerCooling to avoid calling it twice in racy conditions.
The outbound governor can be in the middle of an async demotion in a
call to closePeerConnection while the peerMonitoringLoop in peer state
actions can detect that a warm protocol has finished. The latter will
also call closePeerConnection. This change ensures that there can be
only one (tm) winner.

Author: crocodile-dentist

ouroboros-network/src/Ouroboros/Network/PeerSelection/PeerStateActions.hs

@@ -1058,9 +1058,9 @@ withPeerStateActions PeerStateActionsArguments {
           -- 'unregisterOutboundConnection' could only fail to demote the peer if
           -- connection manager would simultaneously promote it, but this is not
           -- possible.
-          _ <- releaseOutboundConnection spsConnectionManager pchConnectionId
           wasWarm <- atomically (updateUnlessCoolingOrCold pchPeerStatus PeerCooling)
-          when wasWarm $
+          when wasWarm $ do
+            _ <- releaseOutboundConnection spsConnectionManager pchConnectionId
             traceWith spsTracer (PeerStatusChanged (WarmToCooling pchConnectionId))
           return wasWarm