chore(transfer): make Forwarding non-null

e2e/tests/transfer/authz_test.go

@@ -127,7 +127,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_MsgTransfer_Succeeds() {
 			suite.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			nil,
+			transfertypes.Forwarding{},
 		)
 
 		protoAny, err := codectypes.NewAnyWithValue(transferMsg)
@@ -188,7 +188,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_MsgTransfer_Succeeds() {
 			suite.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			nil,
+			transfertypes.Forwarding{},
 		)
 
 		protoAny, err := codectypes.NewAnyWithValue(transferMsg)
@@ -271,7 +271,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_InvalidTransferAuthorizations() {
 				suite.GetTimeoutHeight(ctx, chainB),
 				0,
 				"",
-				nil,
+				transfertypes.Forwarding{},
 			)
 
 			protoAny, err := codectypes.NewAnyWithValue(transferMsg)
@@ -332,7 +332,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_InvalidTransferAuthorizations() {
 				suite.GetTimeoutHeight(ctx, chainB),
 				0,
 				"",
-				nil,
+				transfertypes.Forwarding{},
 			)
 
 			protoAny, err := codectypes.NewAnyWithValue(transferMsg)

e2e/tests/transfer/incentivized_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/cosmos/ibc-go/e2e/testsuite/query"
 	"github.com/cosmos/ibc-go/e2e/testvalues"
 	feetypes "github.com/cosmos/ibc-go/v8/modules/apps/29-fee/types"
+	transfertypes "github.com/cosmos/ibc-go/v8/modules/apps/transfer/types"
 	channeltypes "github.com/cosmos/ibc-go/v8/modules/core/04-channel/types"
 )
 
@@ -211,7 +212,7 @@ func (s *IncentivizedTransferTestSuite) TestMsgPayPacketFee_InvalidReceiverAccou
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			nil,
+			transfertypes.Forwarding{},
 		)
 		txResp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgTransfer)
 		// this message should be successful, as receiver account is not validated on the sending chain.
@@ -350,7 +351,7 @@ func (s *IncentivizedTransferTestSuite) TestMultiMsg_MsgPayPacketFeeSingleSender
 		s.GetTimeoutHeight(ctx, chainB),
 		0,
 		"",
-		nil,
+		transfertypes.Forwarding{},
 	)
 	resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 	s.AssertTxSuccess(resp)

e2e/tests/transfer/upgrades_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/cosmos/ibc-go/e2e/testsuite/query"
 	"github.com/cosmos/ibc-go/e2e/testvalues"
 	feetypes "github.com/cosmos/ibc-go/v8/modules/apps/29-fee/types"
+	transfertypes "github.com/cosmos/ibc-go/v8/modules/apps/transfer/types"
 	channeltypes "github.com/cosmos/ibc-go/v8/modules/core/04-channel/types"
 )
 
@@ -208,7 +209,7 @@ func (s *TransferChannelUpgradesTestSuite) TestChannelUpgrade_WithFeeMiddleware_
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			nil,
+			transfertypes.Forwarding{},
 		)
 		resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 		s.AssertTxSuccess(resp)

e2e/tests/upgrades/upgrade_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/cosmos/ibc-go/e2e/testsuite/query"
 	"github.com/cosmos/ibc-go/e2e/testvalues"
 	feetypes "github.com/cosmos/ibc-go/v8/modules/apps/29-fee/types"
+	transfertypes "github.com/cosmos/ibc-go/v8/modules/apps/transfer/types"
 	v7migrations "github.com/cosmos/ibc-go/v8/modules/core/02-client/migrations/v7"
 	clienttypes "github.com/cosmos/ibc-go/v8/modules/core/02-client/types"
 	connectiontypes "github.com/cosmos/ibc-go/v8/modules/core/03-connection/types"
@@ -966,7 +967,7 @@ func (s *UpgradeTestSuite) TestV8ToV8_1ChainUpgrade_ChannelUpgrades() {
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			nil,
+			transfertypes.Forwarding{},
 		)
 		resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 		s.AssertTxSuccess(resp)

e2e/testsuite/testsuite.go

@@ -625,7 +625,7 @@ func getValidatorsAndFullNodes(chainIdx int) (int, int) {
 }
 
 // GetMsgTransfer returns a MsgTransfer that is constructed based on the channel version
-func GetMsgTransfer(portID, channelID, version string, tokens sdk.Coins, sender, receiver string, timeoutHeight clienttypes.Height, timeoutTimestamp uint64, memo string, forwarding *transfertypes.Forwarding) *transfertypes.MsgTransfer {
+func GetMsgTransfer(portID, channelID, version string, tokens sdk.Coins, sender, receiver string, timeoutHeight clienttypes.Height, timeoutTimestamp uint64, memo string, forwarding transfertypes.Forwarding) *transfertypes.MsgTransfer {
 	if len(tokens) == 0 {
 		panic(errors.New("tokens cannot be empty"))
 	}

e2e/testsuite/tx.go

@@ -30,6 +30,7 @@ import (
 	"github.com/cosmos/ibc-go/e2e/testsuite/sanitize"
 	"github.com/cosmos/ibc-go/e2e/testvalues"
 	feetypes "github.com/cosmos/ibc-go/v8/modules/apps/29-fee/types"
+	transfertypes "github.com/cosmos/ibc-go/v8/modules/apps/transfer/types"
 	clienttypes "github.com/cosmos/ibc-go/v8/modules/core/02-client/types"
 	channeltypes "github.com/cosmos/ibc-go/v8/modules/core/04-channel/types"
 )
@@ -297,7 +298,7 @@ func (s *E2ETestSuite) Transfer(ctx context.Context, chain ibc.Chain, user ibc.W
 		transferVersion = version.AppVersion
 	}
 
-	msg := GetMsgTransfer(portID, channelID, transferVersion, tokens, sender, receiver, timeoutHeight, timeoutTimestamp, memo, nil)
+	msg := GetMsgTransfer(portID, channelID, transferVersion, tokens, sender, receiver, timeoutHeight, timeoutTimestamp, memo, transfertypes.Forwarding{})
 
 	return s.BroadcastMessages(ctx, chain, user, msg)
 }

modules/apps/27-interchain-accounts/host/keeper/relay_test.go

@@ -353,7 +353,7 @@ func (suite *KeeperTestSuite) TestOnRecvPacket() {
 					suite.chainB.GetTimeoutHeight(),
 					0,
 					"",
-					nil,
+					transfertypes.Forwarding{},
 				)
 
 				data, err := icatypes.SerializeCosmosTx(suite.chainA.GetSimApp().AppCodec(), []proto.Message{msg}, encoding)
@@ -389,7 +389,7 @@ func (suite *KeeperTestSuite) TestOnRecvPacket() {
 					suite.chainB.GetTimeoutHeight(),
 					0,
 					"",
-					nil,
+					transfertypes.Forwarding{},
 				)
 
 				data, err := icatypes.SerializeCosmosTx(suite.chainA.GetSimApp().AppCodec(), []proto.Message{msg}, encoding)

modules/apps/29-fee/keeper/events_test.go

@@ -115,7 +115,7 @@ func (suite *KeeperTestSuite) TestDistributeFeeEvent() {
 		path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID,
 		sdk.NewCoins(sdk.NewCoin(sdk.DefaultBondDenom, sdkmath.NewInt(100))), suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(),
 		clienttypes.NewHeight(1, 100), 0, "",
-		nil,
+		transfertypes.Forwarding{},
 	)
 
 	res, err := suite.chainA.SendMsgs(msgPayPacketFee, msgTransfer)

modules/apps/29-fee/transfer_test.go

@@ -46,7 +46,7 @@ func (suite *FeeTestSuite) TestFeeTransfer() {
 
 			msgs := []sdk.Msg{
 				types.NewMsgPayPacketFee(fee, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, suite.chainA.SenderAccount.GetAddress().String(), nil),
-				transfertypes.NewMsgTransfer(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, tc.coinsToTransfer, suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), clienttypes.NewHeight(1, 100), 0, "", nil),
+				transfertypes.NewMsgTransfer(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, tc.coinsToTransfer, suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), clienttypes.NewHeight(1, 100), 0, "", transfertypes.Forwarding{}),
 			}
 
 			res, err := suite.chainA.SendMsgs(msgs...)
@@ -157,7 +157,7 @@ func (suite *FeeTestSuite) TestTransferFeeUpgrade() {
 				fee := types.NewFee(defaultRecvFee, defaultAckFee, defaultTimeoutFee)
 				msgs := []sdk.Msg{
 					types.NewMsgPayPacketFee(fee, path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, suite.chainA.SenderAccount.GetAddress().String(), nil),
-					transfertypes.NewMsgTransfer(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, sdk.NewCoins(ibctesting.TestCoin), suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), clienttypes.NewHeight(1, 100), 0, "", nil),
+					transfertypes.NewMsgTransfer(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID, sdk.NewCoins(ibctesting.TestCoin), suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), clienttypes.NewHeight(1, 100), 0, "", transfertypes.Forwarding{}),
 				}
 
 				res, err := suite.chainA.SendMsgs(msgs...)

modules/apps/callbacks/ibc_middleware_test.go

@@ -24,6 +24,8 @@ import (
 	ibcmock "github.com/cosmos/ibc-go/v8/testing/mock"
 )
 
+var emptyForwarding = transfertypes.Forwarding{}
+
 func (s *CallbacksTestSuite) TestNewIBCMiddleware() {
 	testCases := []struct {
 		name          string
@@ -186,7 +188,7 @@ func (s *CallbacksTestSuite) TestSendPacket() {
 				ibctesting.TestAccAddress,
 				ibctesting.TestAccAddress,
 				fmt.Sprintf(`{"src_callback": {"address": "%s"}}`, simapp.SuccessContract),
-				nil,
+				emptyForwarding,
 			)
 
 			chanCap := s.path.EndpointA.Chain.GetChannelCapability(s.path.EndpointA.ChannelConfig.PortID, s.path.EndpointA.ChannelID)
@@ -328,7 +330,7 @@ func (s *CallbacksTestSuite) TestOnAcknowledgementPacket() {
 				ibctesting.TestAccAddress,
 				ibctesting.TestAccAddress,
 				fmt.Sprintf(`{"src_callback": {"address":"%s", "gas_limit":"%d"}}`, simapp.SuccessContract, userGasLimit),
-				nil,
+				emptyForwarding,
 			)
 
 			packet = channeltypes.Packet{
@@ -494,7 +496,7 @@ func (s *CallbacksTestSuite) TestOnTimeoutPacket() {
 				sdk.NewCoins(ibctesting.TestCoin), s.chainA.SenderAccount.GetAddress().String(),
 				s.chainB.SenderAccount.GetAddress().String(), clienttypes.ZeroHeight(), timeoutTimestamp,
 				fmt.Sprintf(`{"src_callback": {"address":"%s", "gas_limit":"%d"}}`, ibctesting.TestAccAddress, userGasLimit), // set user gas limit above panic level in mock contract keeper
-				nil,
+				emptyForwarding,
 			)
 
 			res, err := s.chainA.SendMsgs(msg)
@@ -662,7 +664,7 @@ func (s *CallbacksTestSuite) TestOnRecvPacket() {
 				ibctesting.TestAccAddress,
 				s.chainB.SenderAccount.GetAddress().String(),
 				fmt.Sprintf(`{"dest_callback": {"address":"%s", "gas_limit":"%d"}}`, ibctesting.TestAccAddress, userGasLimit),
-				nil,
+				emptyForwarding,
 			)
 
 			packet = channeltypes.Packet{
@@ -794,7 +796,7 @@ func (s *CallbacksTestSuite) TestWriteAcknowledgement() {
 				ibctesting.TestAccAddress,
 				s.chainB.SenderAccount.GetAddress().String(),
 				fmt.Sprintf(`{"dest_callback": {"address":"%s", "gas_limit":"600000"}}`, ibctesting.TestAccAddress),
-				nil,
+				emptyForwarding,
 			)
 
 			packet = channeltypes.Packet{
@@ -1018,7 +1020,7 @@ func (s *CallbacksTestSuite) TestUnmarshalPacketDataV1() {
 		Sender:     ibctesting.TestAccAddress,
 		Receiver:   ibctesting.TestAccAddress,
 		Memo:       fmt.Sprintf(`{"src_callback": {"address": "%s"}, "dest_callback": {"address":"%s"}}`, ibctesting.TestAccAddress, ibctesting.TestAccAddress),
-		Forwarding: nil,
+		Forwarding: emptyForwarding,
 	}
 
 	portID := s.path.EndpointA.ChannelConfig.PortID

modules/apps/callbacks/replay_test.go

@@ -330,7 +330,7 @@ func (s *CallbacksTestSuite) ExecuteFailedTransfer(memo string) {
 		s.chainA.SenderAccount.GetAddress().String(),
 		s.chainB.SenderAccount.GetAddress().String(),
 		clienttypes.NewHeight(1, 100), 0, memo,
-		nil,
+		transfertypes.Forwarding{},
 	)
 
 	res, err := s.chainA.SendMsgs(msg)

modules/apps/callbacks/transfer_test.go

@@ -193,7 +193,7 @@ func (s *CallbacksTestSuite) ExecuteTransfer(memo string) {
 		s.chainA.SenderAccount.GetAddress().String(),
 		s.chainB.SenderAccount.GetAddress().String(),
 		clienttypes.NewHeight(1, 100), 0, memo,
-		nil,
+		transfertypes.Forwarding{},
 	)
 
 	res, err := s.chainA.SendMsgs(msg)
@@ -228,7 +228,7 @@ func (s *CallbacksTestSuite) ExecuteTransferTimeout(memo string) {
 		s.chainA.SenderAccount.GetAddress().String(),
 		s.chainB.SenderAccount.GetAddress().String(),
 		timeoutHeight, timeoutTimestamp, memo,
-		nil,
+		transfertypes.Forwarding{},
 	)
 
 	res, err := s.chainA.SendMsgs(msg)

modules/apps/transfer/client/cli/tx.go

@@ -97,7 +97,7 @@ using the {packet-timeout-timestamp} flag. If no timeout value is set then a def
 			}
 
 			// If parsed, set and replace memo.
-			if forwarding != nil {
+			if len(forwarding.Hops) > 0 {
 				forwarding.Memo = memo
 				memo = ""
 			}
@@ -142,22 +142,22 @@ using the {packet-timeout-timestamp} flag. If no timeout value is set then a def
 
 // parseForwarding parses the forwarding flag into a Forwarding object or nil if the flag is not specified. If the flag cannot
 // be parsed or the hops aren't in the portID/channelID format an error is returned.
-func parseForwarding(cmd *cobra.Command) (*types.Forwarding, error) {
+func parseForwarding(cmd *cobra.Command) (types.Forwarding, error) {
 	var hops []types.Hop
 
 	forwardingString, err := cmd.Flags().GetString(flagForwarding)
 	if err != nil {
-		return nil, err
+		return types.Forwarding{}, err
 	}
 	if strings.TrimSpace(forwardingString) == "" {
-		return nil, nil
+		return types.Forwarding{}, nil
 	}
 
 	pairs := strings.Split(forwardingString, ",")
 	for _, pair := range pairs {
 		pairSplit := strings.Split(pair, "/")
 		if len(pairSplit) != 2 {
-			return nil, fmt.Errorf("expected a portID/channelID pair, found %s", pair)
+			return types.Forwarding{}, fmt.Errorf("expected a portID/channelID pair, found %s", pair)
 		}
 
 		hop := types.Hop{PortId: pairSplit[0], ChannelId: pairSplit[1]}

modules/apps/transfer/ibc_module.go

@@ -211,7 +211,7 @@ func (im IBCModule) OnRecvPacket(
 
 	im.keeper.Logger(ctx).Info("successfully handled ICS-20 packet", "sequence", packet.Sequence)
 
-	if data.Forwarding != nil {
+	if len(data.Forwarding.Hops) > 0 {
 		// NOTE: acknowledgement will be written asynchronously
 		return nil
 	}

modules/apps/transfer/ibc_module_test.go

@@ -355,7 +355,7 @@ func (suite *TransferTestSuite) TestOnRecvPacket() {
 				suite.chainA.SenderAccount.GetAddress().String(),
 				suite.chainB.SenderAccount.GetAddress().String(),
 				"",
-				nil,
+				types.Forwarding{},
 			)
 
 			tokensBz, err := json.Marshal(packetData.Tokens)
@@ -476,7 +476,7 @@ func (suite *TransferTestSuite) TestOnTimeoutPacket() {
 				timeoutHeight,
 				0,
 				"",
-				nil,
+				types.Forwarding{},
 			)
 			res, err := suite.chainA.SendMsgs(msg)
 			suite.Require().NoError(err) // message committed

modules/apps/transfer/internal/convert/convert.go

@@ -24,6 +24,6 @@ func PacketDataV1ToV2(packetData types.FungibleTokenPacketData) (types.FungibleT
 		Sender:     packetData.Sender,
 		Receiver:   packetData.Receiver,
 		Memo:       packetData.Memo,
-		Forwarding: nil,
+		Forwarding: types.Forwarding{},
 	}, nil
 }