chore: only send want if there are missing parts (#2322)

Closes #2317

Author: rach-id

consensus/propagation/have_wants.go

@@ -140,10 +140,9 @@ func (blockProp *Reactor) requestFromPeer(ps *PeerState) {
 			}
 
 			var (
-				wants             *proptypes.WantParts
-				parts             *proptypes.CombinedPartSet
-				missingPartsCount int32
-				fullReqs          *bits.BitArray
+				wants    *proptypes.WantParts
+				parts    *proptypes.CombinedPartSet
+				fullReqs *bits.BitArray
 			)
 			for i := min(canSend, int64(len(ps.receivedHaves))); i > 0; {
 				if len(ps.receivedHaves) == 0 {
@@ -159,7 +158,6 @@ func (blockProp *Reactor) requestFromPeer(ps *PeerState) {
 					// haves for a new height, resetting
 					wants = nil
 					parts = nil
-					missingPartsCount = 0
 				}
 
 				if !blockProp.relevantHave(have.height, have.round) {
@@ -173,7 +171,12 @@ func (blockProp *Reactor) requestFromPeer(ps *PeerState) {
 						blockProp.Logger.Error("couldn't find proposal when filtering requests", "height", have.height, "round", have.round)
 						break
 					}
-					missingPartsCount = countRemainingParts(int(parts.Total()), len(parts.BitArray().GetTrueIndices()))
+				}
+
+				missingPartsCount := countRemainingParts(int(parts.Total()), len(parts.BitArray().GetTrueIndices()))
+				if missingPartsCount == 0 {
+					// we can ignore this have in this case
+					continue
 				}
 
 				// don't request a part that is already downloaded
@@ -205,10 +208,9 @@ func (blockProp *Reactor) requestFromPeer(ps *PeerState) {
 
 				if wants == nil {
 					wants = &proptypes.WantParts{
-						Height:            have.height,
-						Round:             have.round,
-						Parts:             bits.NewBitArray(int(parts.Total())),
-						MissingPartsCount: missingPartsCount,
+						Height: have.height,
+						Round:  have.round,
+						Parts:  bits.NewBitArray(int(parts.Total())),
 					}
 				}
 
@@ -221,6 +223,12 @@ func (blockProp *Reactor) requestFromPeer(ps *PeerState) {
 			if wants == nil {
 				continue
 			}
+			missingPartsCount := countRemainingParts(int(parts.Total()), len(parts.BitArray().GetTrueIndices()))
+			if missingPartsCount == 0 {
+				// no need to send the want in this case
+				continue
+			}
+			wants.MissingPartsCount = missingPartsCount
 
 			err := blockProp.sendWantsThenBroadcastHaves(ps, wants)
 			if err != nil {