feat: delete forwarded packet when it is not needed anymore

modules/apps/transfer/keeper/forwarding.go

@@ -44,13 +44,13 @@ func (k Keeper) forwardPacket(ctx sdk.Context, data types.FungibleTokenPacketDat
 }
 
 // ackForwardPacketSuccess writes a successful async acknowledgement for the prevPacket
-func (k Keeper) ackForwardPacketSuccess(ctx sdk.Context, prevPacket channeltypes.Packet) error {
+func (k Keeper) ackForwardPacketSuccess(ctx sdk.Context, prevPacket, forwardedPacket channeltypes.Packet) error {
 	forwardAck := channeltypes.NewResultAcknowledgement([]byte{byte(1)})
-	return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardAck)
+	return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardedPacket, forwardAck)
 }
 
 // ackForwardPacketError reverts the receive packet logic that occurs in the middle chain and writes the async ack for the prevPacket
-func (k Keeper) ackForwardPacketError(ctx sdk.Context, prevPacket channeltypes.Packet, failedPacketData types.FungibleTokenPacketDataV2) error {
+func (k Keeper) ackForwardPacketError(ctx sdk.Context, prevPacket, forwardedPacket channeltypes.Packet, failedPacketData types.FungibleTokenPacketDataV2) error {
 	// the forwarded packet has failed, thus the funds have been refunded to the intermediate address.
 	// we must revert the changes that came from successfully receiving the tokens on our chain
 	// before propagating the error acknowledgement back to original sender chain
@@ -59,27 +59,32 @@ func (k Keeper) ackForwardPacketError(ctx sdk.Context, prevPacket channeltypes.P
 	}
 
 	forwardAck := channeltypes.NewErrorAcknowledgement(types.ErrForwardedPacketFailed)
-	return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardAck)
+	return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardedPacket, forwardAck)
 }
 
 // ackForwardPacketTimeout reverts the receive packet logic that occurs in the middle chain and writes a failed async ack for the prevPacket
-func (k Keeper) ackForwardPacketTimeout(ctx sdk.Context, prevPacket channeltypes.Packet, timeoutPacketData types.FungibleTokenPacketDataV2) error {
+func (k Keeper) ackForwardPacketTimeout(ctx sdk.Context, prevPacket, forwardedPacket channeltypes.Packet, timeoutPacketData types.FungibleTokenPacketDataV2) error {
 	if err := k.revertForwardedPacket(ctx, prevPacket, timeoutPacketData); err != nil {
 		return err
 	}
 
 	forwardAck := channeltypes.NewErrorAcknowledgement(types.ErrForwardedPacketTimedOut)
-	return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardAck)
+	return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardedPacket, forwardAck)
 }
 
 // acknowledgeForwardedPacket writes the async acknowledgement for packet
-func (k Keeper) acknowledgeForwardedPacket(ctx sdk.Context, packet channeltypes.Packet, ack channeltypes.Acknowledgement) error {
+func (k Keeper) acknowledgeForwardedPacket(ctx sdk.Context, packet, forwardedPacket channeltypes.Packet, ack channeltypes.Acknowledgement) error {
 	capability, ok := k.scopedKeeper.GetCapability(ctx, host.ChannelCapabilityPath(packet.DestinationPort, packet.DestinationChannel))
 	if !ok {
 		return errorsmod.Wrap(channeltypes.ErrChannelCapabilityNotFound, "module does not own channel capability")
 	}
 
-	return k.ics4Wrapper.WriteAcknowledgement(ctx, capability, packet, ack)
+	if err := k.ics4Wrapper.WriteAcknowledgement(ctx, capability, packet, ack); err != nil {
+		return err
+	}
+
+	k.deleteForwardedPacket(ctx, forwardedPacket.SourcePort, forwardedPacket.SourceChannel, forwardedPacket.Sequence)
+	return nil
 }
 
 // revertForwardedPacket reverts the logic of receive packet that occurs in the middle chains during a packet forwarding.

modules/apps/transfer/keeper/keeper.go

@@ -328,3 +328,11 @@ func (k Keeper) GetForwardedPacket(ctx sdk.Context, portID, channelID string, se
 
 	return storedPacket, true
 }
+
+// deleteForwardedPacket deletes the forwarded packet from the store.
+func (k Keeper) deleteForwardedPacket(ctx sdk.Context, portID, channelID string, sequence uint64) {
+	store := ctx.KVStore(k.storeKey)
+	packetKey := types.PacketForwardKey(portID, channelID, sequence)
+
+	store.Delete(packetKey)
+}

modules/apps/transfer/keeper/relay.go

@@ -285,7 +285,7 @@ func (k Keeper) OnAcknowledgementPacket(ctx sdk.Context, packet channeltypes.Pac
 	switch ack.Response.(type) {
 	case *channeltypes.Acknowledgement_Result:
 		if isForwarded {
-			return k.ackForwardPacketSuccess(ctx, prevPacket)
+			return k.ackForwardPacketSuccess(ctx, prevPacket, packet)
 		}
 
 		// the acknowledgement succeeded on the receiving chain so nothing
@@ -297,7 +297,7 @@ func (k Keeper) OnAcknowledgementPacket(ctx sdk.Context, packet channeltypes.Pac
 			return err
 		}
 		if isForwarded {
-			return k.ackForwardPacketError(ctx, prevPacket, data)
+			return k.ackForwardPacketError(ctx, prevPacket, packet, data)
 		}
 
 		return nil
@@ -316,7 +316,7 @@ func (k Keeper) OnTimeoutPacket(ctx sdk.Context, packet channeltypes.Packet, dat
 
 	prevPacket, isForwarded := k.GetForwardedPacket(ctx, packet.SourcePort, packet.SourceChannel, packet.Sequence)
 	if isForwarded {
-		return k.ackForwardPacketTimeout(ctx, prevPacket, data)
+		return k.ackForwardPacketTimeout(ctx, prevPacket, packet, data)
 	}
 
 	return nil

modules/apps/transfer/keeper/relay_forwarding_test.go

@@ -317,6 +317,10 @@ func (suite *KeeperTestSuite) TestSimplifiedHappyPathForwarding() {
 	err = path2.EndpointB.UpdateClient()
 	suite.Require().NoError(err)
 
+	// B should now have deleted the forwarded packet.
+	_, found := suite.chainB.GetSimApp().TransferKeeper.GetForwardedPacket(suite.chainB.GetContext(), packetFromAtoB.DestinationPort, packetFromAtoB.DestinationChannel, packetFromAtoB.Sequence)
+	suite.Require().False(found, "Chain B should have deleted its forwarded packet")
+
 	result, err = path2.EndpointB.RecvPacketWithResult(packetFromBtoC)
 	suite.Require().NoError(err)
 	suite.Require().NotNil(result)
@@ -562,6 +566,10 @@ func (suite *KeeperTestSuite) TestAcknowledgementFailureScenario5Forwarding() {
 	err = path1.EndpointB.AcknowledgePacket(packetFromBtoA, errorAckOnA.Acknowledgement())
 	suite.Require().NoError(err)
 
+	// Check that B deleted the forwarded packet.
+	_, found = suite.chainB.GetSimApp().TransferKeeper.GetForwardedPacket(suite.chainB.GetContext(), forwardedPacket.SourcePort, forwardedPacket.SourceChannel, forwardedPacket.Sequence)
+	suite.Require().False(found, "chain B should have deleted the forwarded packet mapping")
+
 	// Check that Escrow B has been refunded amount
 	coin = sdk.NewCoin(denomAB.IBCDenom(), amount)
 	totalEscrowChainB = suite.chainB.GetSimApp().TransferKeeper.GetTotalEscrowForDenom(suite.chainB.GetContext(), coin.GetDenom())