Improve comments on message Ops (#3987)

Author: StephenButtolph

message/ops.go

@@ -15,8 +15,8 @@ import (
 type Op byte
 
 // Types of messages that may be sent between nodes
-// Note: If you add a new parseable Op below, you must also add it to ops
-// (declared below)
+// Note: If you add a new parseable Op below, you must add it to either
+// [UnrequestedOps] or [FailedToResponseOps].
 const (
 	// Handshake:
 	PingOp Op = iota
@@ -62,102 +62,23 @@ const (
 )
 
 var (
-	HandshakeOps = []Op{
-		PingOp,
-		PongOp,
-		HandshakeOp,
-		GetPeerListOp,
-		PeerListOp,
-	}
-
-	// List of all consensus request message types
-	ConsensusRequestOps = []Op{
-		GetStateSummaryFrontierOp,
-		GetAcceptedStateSummaryOp,
+	// UnrequestedOps are operations that are expected to be seen without having
+	// requested them. For example, a peer may receive a Get request for a block
+	// without having sent a message previously.
+	UnrequestedOps = set.Of(
 		GetAcceptedFrontierOp,
 		GetAcceptedOp,
 		GetAncestorsOp,
 		GetOp,
 		PushQueryOp,
 		PullQueryOp,
 		AppRequestOp,
-	}
-	ConsensusResponseOps = []Op{
-		StateSummaryFrontierOp,
-		AcceptedStateSummaryOp,
-		AcceptedFrontierOp,
-		AcceptedOp,
-		AncestorsOp,
-		PutOp,
-		ChitsOp,
-		AppResponseOp,
-		AppErrorOp,
-	}
-	// AppGossip is the only message that is sent unrequested without the
-	// expectation of a response
-	ConsensusExternalOps = append(
-		ConsensusRequestOps,
-		append(
-			ConsensusResponseOps,
-			AppGossipOp,
-		)...,
-	)
-	ConsensusInternalOps = []Op{
-		GetStateSummaryFrontierFailedOp,
-		GetAcceptedStateSummaryFailedOp,
-		GetAcceptedFrontierFailedOp,
-		GetAcceptedFailedOp,
-		GetAncestorsFailedOp,
-		GetFailedOp,
-		QueryFailedOp,
-		ConnectedOp,
-		DisconnectedOp,
-		NotifyOp,
-		GossipRequestOp,
-	}
-	ConsensusOps = append(ConsensusExternalOps, ConsensusInternalOps...)
-
-	ExternalOps = append(ConsensusExternalOps, HandshakeOps...)
-
-	SynchronousOps = []Op{
-		// State sync
+		AppGossipOp,
 		GetStateSummaryFrontierOp,
-		GetStateSummaryFrontierFailedOp,
-		StateSummaryFrontierOp,
 		GetAcceptedStateSummaryOp,
-		GetAcceptedStateSummaryFailedOp,
-		AcceptedStateSummaryOp,
-		// Bootstrapping
-		GetAcceptedFrontierOp,
-		GetAcceptedFrontierFailedOp,
-		AcceptedFrontierOp,
-		GetAcceptedOp,
-		GetAcceptedFailedOp,
-		AcceptedOp,
-		GetAncestorsOp,
-		GetAncestorsFailedOp,
-		AncestorsOp,
-		// Consensus
-		GetOp,
-		GetFailedOp,
-		PutOp,
-		PushQueryOp,
-		PullQueryOp,
-		QueryFailedOp,
-		ChitsOp,
-		// Internal
-		ConnectedOp,
-		DisconnectedOp,
-	}
-
-	AsynchronousOps = []Op{
-		// Application
-		AppRequestOp,
-		AppErrorOp,
-		AppGossipOp,
-		AppResponseOp,
-	}
-
+	)
+	// FailedToResponseOps maps response failure messages to their successful
+	// counterparts.
 	FailedToResponseOps = map[Op]Op{
 		GetStateSummaryFrontierFailedOp: StateSummaryFrontierOp,
 		GetAcceptedStateSummaryFailedOp: AcceptedStateSummaryOp,
@@ -168,18 +89,6 @@ var (
 		QueryFailedOp:                   ChitsOp,
 		AppErrorOp:                      AppResponseOp,
 	}
-	UnrequestedOps = set.Of(
-		GetAcceptedFrontierOp,
-		GetAcceptedOp,
-		GetAncestorsOp,
-		GetOp,
-		PushQueryOp,
-		PullQueryOp,
-		AppRequestOp,
-		AppGossipOp,
-		GetStateSummaryFrontierOp,
-		GetAcceptedStateSummaryOp,
-	)
 
 	errUnknownMessageType = errors.New("unknown message type")
 )