Remove lists from Chits messages

message/inbound_msg_builder.go

@@ -243,22 +243,18 @@ func InboundPullQuery(
 func InboundChits(
 	chainID ids.ID,
 	requestID uint32,
-	preferredContainerIDs []ids.ID,
-	acceptedContainerIDs []ids.ID,
+	preferredID ids.ID,
+	acceptedID ids.ID,
 	nodeID ids.NodeID,
 ) InboundMessage {
-	preferredContainerIDBytes := make([][]byte, len(preferredContainerIDs))
-	encodeIDs(preferredContainerIDs, preferredContainerIDBytes)
-	acceptedContainerIDBytes := make([][]byte, len(acceptedContainerIDs))
-	encodeIDs(acceptedContainerIDs, acceptedContainerIDBytes)
 	return &inboundMessage{
 		nodeID: nodeID,
 		op:     ChitsOp,
 		message: &p2p.Chits{
-			ChainId:               chainID[:],
-			RequestId:             requestID,
-			PreferredContainerIds: preferredContainerIDBytes,
-			AcceptedContainerIds:  acceptedContainerIDBytes,
+			ChainId:     chainID[:],
+			RequestId:   requestID,
+			PreferredId: preferredID[:],
+			AcceptedId:  acceptedID[:],
 		},
 		expiration: mockable.MaxTime,
 	}

message/inbound_msg_builder_test.go

@@ -327,8 +327,8 @@ func TestInboundMsgBuilder(t *testing.T) {
 			msg := InboundChits(
 				chainID,
 				requestID,
-				containerIDs,
-				acceptedContainerIDs,
+				containerIDs[0],
+				acceptedContainerIDs[0],
 				nodeID,
 			)
 
@@ -339,18 +339,8 @@ func TestInboundMsgBuilder(t *testing.T) {
 			require.True(ok)
 			require.Equal(chainID[:], innerMsg.ChainId)
 			require.Equal(requestID, innerMsg.RequestId)
-			containerIDsBytes := make([][]byte, len(containerIDs))
-			for i, id := range containerIDs {
-				id := id
-				containerIDsBytes[i] = id[:]
-			}
-			require.Equal(containerIDsBytes, innerMsg.PreferredContainerIds)
-			acceptedContainerIDsBytes := make([][]byte, len(acceptedContainerIDs))
-			for i, id := range acceptedContainerIDs {
-				id := id
-				acceptedContainerIDsBytes[i] = id[:]
-			}
-			require.Equal(acceptedContainerIDsBytes, innerMsg.AcceptedContainerIds)
+			require.Equal(containerIDs[0][:], innerMsg.PreferredId)
+			require.Equal(acceptedContainerIDs[0][:], innerMsg.AcceptedId)
 		},
 	)
 

message/messages_test.go

@@ -653,9 +653,9 @@ func TestMessage(t *testing.T) {
 			msg: &p2p.Message{
 				Message: &p2p.Message_Chits{
 					Chits: &p2p.Chits{
-						ChainId:               testID[:],
-						RequestId:             1,
-						PreferredContainerIds: [][]byte{testID[:], testID[:]},
+						ChainId:     testID[:],
+						RequestId:   1,
+						PreferredId: testID[:],
 					},
 				},
 			},

message/outbound_msg_builder.go

@@ -144,8 +144,8 @@ type OutboundMsgBuilder interface {
 	Chits(
 		chainID ids.ID,
 		requestID uint32,
-		preferredContainerIDs []ids.ID,
-		acceptedContainerIDs []ids.ID,
+		preferredID ids.ID,
+		acceptedID ids.ID,
 	) (OutboundMessage, error)
 
 	AppRequest(
@@ -599,21 +599,17 @@ func (b *outMsgBuilder) PullQuery(
 func (b *outMsgBuilder) Chits(
 	chainID ids.ID,
 	requestID uint32,
-	preferredContainerIDs []ids.ID,
-	acceptedContainerIDs []ids.ID,
+	preferredID ids.ID,
+	acceptedID ids.ID,
 ) (OutboundMessage, error) {
-	preferredContainerIDBytes := make([][]byte, len(preferredContainerIDs))
-	encodeIDs(preferredContainerIDs, preferredContainerIDBytes)
-	acceptedContainerIDBytes := make([][]byte, len(acceptedContainerIDs))
-	encodeIDs(acceptedContainerIDs, acceptedContainerIDBytes)
 	return b.builder.createOutbound(
 		&p2p.Message{
 			Message: &p2p.Message_Chits{
 				Chits: &p2p.Chits{
-					ChainId:               chainID[:],
-					RequestId:             requestID,
-					PreferredContainerIds: preferredContainerIDBytes,
-					AcceptedContainerIds:  acceptedContainerIDBytes,
+					ChainId:     chainID[:],
+					RequestId:   requestID,
+					PreferredId: preferredID[:],
+					AcceptedId:  acceptedID[:],
 				},
 			},
 		},

proto/p2p/p2p.proto

@@ -313,23 +313,22 @@ message PullQuery {
   EngineType engine_type = 5;
 }
 
-// Message that contains the votes/preferences of the local node,
-// in response to "push_query" or "pull_query" (e.g., preferred frontier).
+// Message that contains the votes/preferences of the node. It is sent in
+// response to a "push_query" or "pull_query" request.
 //
-// On receiving "chits", the engine issues those preferred containers of vertices/blocks
-// to the consensus. If the received container is not found, it responds back with
-// "get" message to fetch the missing container from the remote peer.
+// Upon receiving "chits", the engine will attempt to issue the preferred block
+// into consensus. If the referenced block is not locally available, the engine
+// will respond with a "get" message to fetch the missing block from the remote
+// peer.
 message Chits {
   reserved 5; // Until Cortina upgrade is activated
 
   bytes chain_id = 1;
   uint32 request_id = 2;
-  // Represents the current preferred frontier.
-  // TODO: Remove `repeated` once all chains are running Snowman.
-  repeated bytes preferred_container_ids = 3;
-  // Represents the current accepted frontier.
-  // TODO: Remove `repeated` once all chains are running Snowman.
-  repeated bytes accepted_container_ids = 4;
+  // Represents the current preferred block.
+  bytes preferred_id = 3;
+  // Represents the last accepted block.
+  bytes accepted_id = 4;
 }
 
 message AppRequest {

snow/engine/common/engine.go

@@ -390,8 +390,8 @@ type ChitsHandler interface {
 		ctx context.Context,
 		validatorID ids.NodeID,
 		requestID uint32,
-		preferredContainerIDs []ids.ID,
-		acceptedContainerIDs []ids.ID,
+		preferredID ids.ID,
+		acceptedID ids.ID,
 	) error
 
 	// Notify this engine that a query it issued has failed.

snow/engine/common/no_ops_handlers.go

@@ -240,12 +240,14 @@ func NewNoOpChitsHandler(log logging.Logger) ChitsHandler {
 	return &noOpChitsHandler{log: log}
 }
 
-func (nop *noOpChitsHandler) Chits(_ context.Context, nodeID ids.NodeID, requestID uint32, _, _ []ids.ID) error {
+func (nop *noOpChitsHandler) Chits(_ context.Context, nodeID ids.NodeID, requestID uint32, preferredID, acceptedID ids.ID) error {
 	nop.log.Debug("dropping request",
 		zap.String("reason", "unhandled by this gear"),
 		zap.Stringer("messageOp", message.ChitsOp),
 		zap.Stringer("nodeID", nodeID),
 		zap.Uint32("requestID", requestID),
+		zap.Stringer("preferredID", preferredID),
+		zap.Stringer("acceptedID", acceptedID),
 	)
 	return nil
 }

snow/engine/common/sender.go

@@ -117,7 +117,7 @@ type QuerySender interface {
 	SendPullQuery(ctx context.Context, nodeIDs set.Set[ids.NodeID], requestID uint32, containerID ids.ID)
 
 	// Send chits to the specified node
-	SendChits(ctx context.Context, nodeID ids.NodeID, requestID uint32, votes []ids.ID, accepted []ids.ID)
+	SendChits(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredID ids.ID, acceptedID ids.ID)
 }
 
 // Gossiper defines how a consensus engine gossips a container on the accepted

snow/engine/common/test_engine.go

@@ -115,7 +115,7 @@ type EngineTest struct {
 	PutF, PushQueryF                           func(ctx context.Context, nodeID ids.NodeID, requestID uint32, container []byte) error
 	AncestorsF                                 func(ctx context.Context, nodeID ids.NodeID, requestID uint32, containers [][]byte) error
 	AcceptedFrontierF, GetAcceptedF, AcceptedF func(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredIDs []ids.ID) error
-	ChitsF                                     func(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredIDs []ids.ID, acceptedIDs []ids.ID) error
+	ChitsF                                     func(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredID ids.ID, acceptedID ids.ID) error
 	GetStateSummaryFrontierF, GetStateSummaryFrontierFailedF, GetAcceptedStateSummaryFailedF,
 	GetAcceptedFrontierF, GetFailedF, GetAncestorsFailedF,
 	QueryFailedF, GetAcceptedFrontierFailedF, GetAcceptedFailedF func(ctx context.Context, nodeID ids.NodeID, requestID uint32) error
@@ -631,9 +631,9 @@ func (e *EngineTest) AppGossip(ctx context.Context, nodeID ids.NodeID, msg []byt
 	return errAppGossip
 }
 
-func (e *EngineTest) Chits(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredIDs []ids.ID, acceptedIDs []ids.ID) error {
+func (e *EngineTest) Chits(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredID ids.ID, acceptedID ids.ID) error {
 	if e.ChitsF != nil {
-		return e.ChitsF(ctx, nodeID, requestID, preferredIDs, acceptedIDs)
+		return e.ChitsF(ctx, nodeID, requestID, preferredID, acceptedID)
 	}
 	if !e.CantChits {
 		return nil