chore: move back to nullable forwarding.

e2e/tests/transfer/authz_test.go

@@ -131,7 +131,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_MsgTransfer_Succeeds() {
 			suite.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			transfertypes.Forwarding{},
+			nil,
 		)
 
 		protoAny, err := codectypes.NewAnyWithValue(transferMsg)
@@ -192,7 +192,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_MsgTransfer_Succeeds() {
 			suite.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			transfertypes.Forwarding{},
+			nil,
 		)
 
 		protoAny, err := codectypes.NewAnyWithValue(transferMsg)
@@ -276,7 +276,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_InvalidTransferAuthorizations() {
 				suite.GetTimeoutHeight(ctx, chainB),
 				0,
 				"",
-				transfertypes.Forwarding{},
+				nil,
 			)
 
 			protoAny, err := codectypes.NewAnyWithValue(transferMsg)
@@ -337,7 +337,7 @@ func (suite *AuthzTransferTestSuite) TestAuthz_InvalidTransferAuthorizations() {
 				suite.GetTimeoutHeight(ctx, chainB),
 				0,
 				"",
-				transfertypes.Forwarding{},
+				nil,
 			)
 
 			protoAny, err := codectypes.NewAnyWithValue(transferMsg)

e2e/tests/transfer/incentivized_test.go

@@ -20,7 +20,6 @@ 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"
 )
 
@@ -217,7 +216,7 @@ func (s *IncentivizedTransferTestSuite) TestMsgPayPacketFee_InvalidReceiverAccou
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			transfertypes.Forwarding{},
+			nil,
 		)
 		txResp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgTransfer)
 		// this message should be successful, as receiver account is not validated on the sending chain.
@@ -356,7 +355,7 @@ func (s *IncentivizedTransferTestSuite) TestMultiMsg_MsgPayPacketFeeSingleSender
 		s.GetTimeoutHeight(ctx, chainB),
 		0,
 		"",
-		transfertypes.Forwarding{},
+		nil,
 	)
 	resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 	s.AssertTxSuccess(resp)

e2e/tests/transfer/upgradesv1_test.go

@@ -306,7 +306,7 @@ func (s *TransferChannelUpgradesV1TestSuite) TestChannelUpgrade_WithFeeMiddlewar
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			transfertypes.Forwarding{},
+			nil,
 		)
 		resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 		s.AssertTxSuccess(resp)

e2e/tests/transfer/upgradesv2_test.go

@@ -213,7 +213,7 @@ func (s *TransferChannelUpgradesTestSuite) TestChannelUpgrade_WithFeeMiddleware_
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			transfertypes.Forwarding{},
+			nil,
 		)
 		resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 		s.AssertTxSuccess(resp)

e2e/tests/upgrades/upgrade_test.go

@@ -29,7 +29,6 @@ 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"
@@ -979,7 +978,7 @@ func (s *UpgradeTestSuite) TestV8ToV8_1ChainUpgrade_ChannelUpgrades() {
 			s.GetTimeoutHeight(ctx, chainB),
 			0,
 			"",
-			transfertypes.Forwarding{},
+			nil,
 		)
 		resp := s.BroadcastMessages(ctx, chainA, chainAWallet, msgPayPacketFee, msgTransfer)
 		s.AssertTxSuccess(resp)

e2e/testsuite/testsuite.go

@@ -706,7 +706,7 @@ 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

@@ -30,7 +30,6 @@ 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"
 )
@@ -300,7 +299,7 @@ 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, transfertypes.Forwarding{})
+	msg := GetMsgTransfer(portID, channelID, transferVersion, tokens, sender, receiver, timeoutHeight, timeoutTimestamp, memo, nil)
 
 	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,
 					"",
-					transfertypes.Forwarding{},
+					nil,
 				)
 
 				data, err := icatypes.SerializeCosmosTx(suite.chainA.GetSimApp().AppCodec(), []proto.Message{msg}, encoding)
@@ -389,7 +389,7 @@ func (suite *KeeperTestSuite) TestOnRecvPacket() {
 					suite.chainB.GetTimeoutHeight(),
 					0,
 					"",
-					transfertypes.Forwarding{},
+					nil,
 				)
 
 				data, err := icatypes.SerializeCosmosTx(suite.chainA.GetSimApp().AppCodec(), []proto.Message{msg}, encoding)

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

@@ -113,7 +113,7 @@ func (suite *KeeperTestSuite) TestDistributeFeeEvent() {
 		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{},
+		nil,
 	)
 
 	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, "", transfertypes.Forwarding{}),
+				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),
 			}
 
 			res, err := suite.chainA.SendMsgs(msgs...)
@@ -156,7 +156,7 @@ 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, "", transfertypes.Forwarding{}),
+					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),
 				}
 
 				res, err := suite.chainA.SendMsgs(msgs...)

modules/apps/callbacks/ibc_middleware_test.go

@@ -496,7 +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
-				transfertypes.Forwarding{},
+				nil,
 			)
 
 			res, err := s.chainA.SendMsgs(msg)

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,
-		transfertypes.Forwarding{},
+		nil,
 	)
 
 	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,
-		transfertypes.Forwarding{},
+		nil,
 	)
 
 	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,
-		transfertypes.Forwarding{},
+		nil,
 	)
 
 	res, err := s.chainA.SendMsgs(msg)

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

@@ -143,22 +143,22 @@ to first unwind IBC tokens to their native chain and then forward them to the fi
 
 // 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 types.Forwarding{}, err
+		return nil, err
 	}
 	if strings.TrimSpace(forwardingString) == "" {
-		return types.Forwarding{}, nil
+		return nil, nil
 	}
 
 	pairs := strings.Split(forwardingString, ",")
 	for _, pair := range pairs {
 		pairSplit := strings.Split(pair, "/")
 		if len(pairSplit) != 2 {
-			return types.Forwarding{}, fmt.Errorf("expected a portID/channelID pair, found %s", pair)
+			return nil, fmt.Errorf("expected a portID/channelID pair, found %s", pair)
 		}
 
 		hop := types.NewHop(pairSplit[0], pairSplit[1])
@@ -167,7 +167,7 @@ func parseForwarding(cmd *cobra.Command) (types.Forwarding, error) {
 
 	unwind, err := cmd.Flags().GetBool(flagUnwind)
 	if err != nil {
-		return types.Forwarding{}, err
+		return nil, err
 	}
 
 	return types.NewForwarding(unwind, hops...), nil

modules/apps/transfer/ibc_module_test.go

@@ -490,7 +490,7 @@ func (suite *TransferTestSuite) TestOnTimeoutPacket() {
 				timeoutHeight,
 				0,
 				"",
-				types.Forwarding{},
+				nil,
 			)
 			res, err := suite.chainA.SendMsgs(msg)
 			suite.Require().NoError(err) // message committed

modules/apps/transfer/keeper/forwarding.go

@@ -14,7 +14,7 @@ import (
 
 // forwardPacket forwards a fungible FungibleTokenPacketDataV2 to the next hop in the forwarding path.
 func (k Keeper) forwardPacket(ctx sdk.Context, data types.FungibleTokenPacketDataV2, packet channeltypes.Packet, receivedCoins sdk.Coins) error {
-	var nextForwardingPath types.Forwarding
+	var nextForwardingPath *types.Forwarding
 	if len(data.Forwarding.Hops) > 1 {
 		// remove the first hop since we are going to send to the first hop now and we want to propagate the rest of the hops to the receiver
 		nextForwardingPath = types.NewForwarding(false, data.Forwarding.Hops[1:]...)

modules/apps/transfer/keeper/invariants_test.go

@@ -56,7 +56,7 @@ func (suite *KeeperTestSuite) TestTotalEscrowPerDenomInvariant() {
 				suite.chainA.SenderAccount.GetAddress().String(),
 				suite.chainB.SenderAccount.GetAddress().String(),
 				suite.chainA.GetTimeoutHeight(), 0, "",
-				types.Forwarding{},
+				nil,
 			)
 
 			res, err := suite.chainA.SendMsgs(msg)

modules/apps/transfer/keeper/mbt_relay_test.go

@@ -358,7 +358,7 @@ func (suite *KeeperTestSuite) TestModelBasedRelay() {
 							tc.packet.Data.Receiver,
 							suite.chainA.GetTimeoutHeight(), 0, // only use timeout height
 							"",
-							types.Forwarding{},
+							nil,
 						)
 
 						_, err = suite.chainB.GetSimApp().TransferKeeper.Transfer(suite.chainB.GetContext(), msg)

modules/apps/transfer/keeper/msg_server.go

@@ -36,7 +36,7 @@ func (k Keeper) Transfer(goCtx context.Context, msg *types.MsgTransfer) (*types.
 		return nil, errorsmod.Wrapf(ibcerrors.ErrUnauthorized, "%s is not allowed to send funds", sender)
 	}
 
-	if msg.Forwarding.Unwind {
+	if msg.Forwarding.GetUnwind() {
 		msg, err = k.unwindHops(ctx, msg)
 		if err != nil {
 			return nil, err
@@ -45,7 +45,7 @@ func (k Keeper) Transfer(goCtx context.Context, msg *types.MsgTransfer) (*types.
 
 	sequence, err := k.sendTransfer(
 		ctx, msg.SourcePort, msg.SourceChannel, coins, sender, msg.Receiver, msg.TimeoutHeight, msg.TimeoutTimestamp,
-		msg.Memo, msg.Forwarding.Hops)
+		msg.Memo, msg.Forwarding.GetHops())
 	if err != nil {
 		return nil, err
 	}

modules/apps/transfer/keeper/msg_server_test.go

@@ -136,7 +136,7 @@ func (suite *KeeperTestSuite) TestMsgTransfer() {
 				suite.chainB.SenderAccount.GetAddress().String(),
 				suite.chainB.GetTimeoutHeight(), 0, // only use timeout height
 				"memo",
-				types.Forwarding{},
+				nil,
 			)
 
 			// send some coins of the second denom from bank module to the sender account as well
@@ -159,7 +159,7 @@ func (suite *KeeperTestSuite) TestMsgTransfer() {
 			tokensBz, err := json.Marshal(types.Tokens(tokens))
 			suite.Require().NoError(err)
 
-			forwardingHopsBz, err := json.Marshal(msg.Forwarding.Hops)
+			forwardingHopsBz, err := json.Marshal(msg.Forwarding.GetHops())
 			suite.Require().NoError(err)
 
 			res, err := suite.chainA.GetSimApp().TransferKeeper.Transfer(ctx, msg)

modules/apps/transfer/keeper/relay_forwarding_test.go

@@ -614,7 +614,7 @@ func (suite *KeeperTestSuite) TestAcknowledgementFailureWithMiddleChainAsNativeT
 		setupReceiver.GetAddress().String(),
 		suite.chainB.GetTimeoutHeight(),
 		0, "",
-		types.Forwarding{},
+		nil,
 	)
 
 	result, err := suite.chainB.SendMsgs(setupTransferMsg)
@@ -899,9 +899,7 @@ func (suite *KeeperTestSuite) TestOnTimeoutPacketForwarding() {
 
 	originalABalance := suite.chainA.GetSimApp().BankKeeper.GetBalance(suite.chainA.GetContext(), sender.GetAddress(), coin.Denom)
 
-	forwarding := types.Forwarding{
-		Hops: []types.Hop{types.NewHop(pathBtoC.EndpointA.ChannelConfig.PortID, pathBtoC.EndpointA.ChannelID)},
-	}
+	forwarding := types.NewForwarding(false, types.NewHop(pathBtoC.EndpointA.ChannelConfig.PortID, pathBtoC.EndpointA.ChannelID))
 
 	transferMsg := types.NewMsgTransfer(
 		pathAtoB.EndpointA.ChannelConfig.PortID,

modules/apps/transfer/keeper/relay_test.go

@@ -23,7 +23,7 @@ import (
 )
 
 var (
-	emptyForwarding           = types.Forwarding{}
+	emptyForwarding           *types.Forwarding
 	emptyForwardingPacketData = types.ForwardingPacketData{}
 )
 
@@ -36,7 +36,7 @@ func (suite *KeeperTestSuite) TestSendTransfer() {
 		sender          sdk.AccAddress
 		timeoutHeight   clienttypes.Height
 		memo            string
-		forwarding      types.Forwarding
+		forwarding      *types.Forwarding
 		expEscrowAmount sdkmath.Int // total amount in escrow for denom on receiving chain
 	)
 

modules/apps/transfer/transfer_test.go

@@ -80,7 +80,7 @@ func (suite *TransferTestSuite) TestHandleMsgTransfer() {
 			}
 
 			// send from chainA to chainB
-			msg := types.NewMsgTransfer(pathAToB.EndpointA.ChannelConfig.PortID, pathAToB.EndpointA.ChannelID, originalCoins, suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), timeoutHeight, 0, "", types.Forwarding{})
+			msg := types.NewMsgTransfer(pathAToB.EndpointA.ChannelConfig.PortID, pathAToB.EndpointA.ChannelID, originalCoins, suite.chainA.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), timeoutHeight, 0, "", nil)
 			res, err := suite.chainA.SendMsgs(msg)
 			suite.Require().NoError(err) // message committed
 
@@ -120,7 +120,7 @@ func (suite *TransferTestSuite) TestHandleMsgTransfer() {
 			traceBToC := types.NewHop(pathBToC.EndpointB.ChannelConfig.PortID, pathBToC.EndpointB.ChannelID)
 
 			// send from chainB to chainC
-			msg = types.NewMsgTransfer(pathBToC.EndpointA.ChannelConfig.PortID, pathBToC.EndpointA.ChannelID, coinsSentFromAToB, suite.chainB.SenderAccount.GetAddress().String(), suite.chainC.SenderAccount.GetAddress().String(), timeoutHeight, 0, "", types.Forwarding{})
+			msg = types.NewMsgTransfer(pathBToC.EndpointA.ChannelConfig.PortID, pathBToC.EndpointA.ChannelID, coinsSentFromAToB, suite.chainB.SenderAccount.GetAddress().String(), suite.chainC.SenderAccount.GetAddress().String(), timeoutHeight, 0, "", nil)
 			res, err = suite.chainB.SendMsgs(msg)
 			suite.Require().NoError(err) // message committed
 
@@ -149,7 +149,7 @@ func (suite *TransferTestSuite) TestHandleMsgTransfer() {
 			}
 
 			// send from chainC back to chainB
-			msg = types.NewMsgTransfer(pathBToC.EndpointB.ChannelConfig.PortID, pathBToC.EndpointB.ChannelID, coinsSentFromBToC, suite.chainC.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), timeoutHeight, 0, "", types.Forwarding{})
+			msg = types.NewMsgTransfer(pathBToC.EndpointB.ChannelConfig.PortID, pathBToC.EndpointB.ChannelID, coinsSentFromBToC, suite.chainC.SenderAccount.GetAddress().String(), suite.chainB.SenderAccount.GetAddress().String(), timeoutHeight, 0, "", nil)
 			res, err = suite.chainC.SendMsgs(msg)
 			suite.Require().NoError(err) // message committed
 

modules/apps/transfer/types/forwarding.go

@@ -11,16 +11,16 @@ import (
 const MaximumNumberOfForwardingHops = 8 // denotes the maximum number of forwarding hops allowed
 
 // NewForwarding creates a new Forwarding instance given an unwind value and a variable number of hops.
-func NewForwarding(unwind bool, hops ...Hop) Forwarding {
-	return Forwarding{
+func NewForwarding(unwind bool, hops ...Hop) *Forwarding {
+	return &Forwarding{
 		Unwind: unwind,
 		Hops:   hops,
 	}
 }
 
 // Validate performs a basic validation of the Forwarding fields.
 func (f Forwarding) Validate() error {
-	if err := validateHops(f.Hops); err != nil {
+	if err := validateHops(f.GetHops()); err != nil {
 		return errorsmod.Wrapf(ErrInvalidForwarding, "invalid hops in forwarding")
 	}