From ad7412dc4d2458acf28ae03e5d367bb5833478c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 11:20:26 +0200
Subject: [PATCH 1/9] refactor: initial introduction of typed trace

---
 .../apps/transfer/internal/convert/convert.go |   6 +-
 .../transfer/internal/convert/convert_test.go |  41 ++++--
 modules/apps/transfer/keeper/relay.go         |   4 +-
 modules/apps/transfer/types/denom.go          |  28 ++--
 modules/apps/transfer/types/query.pb.go       |   4 +-
 modules/apps/transfer/types/token.go          |  26 +---
 modules/apps/transfer/types/token.pb.go       |  79 +++++-----
 modules/apps/transfer/types/token_test.go     | 136 +++++++-----------
 modules/apps/transfer/types/trace.go          |  29 ++++
 .../ibc/applications/transfer/v1/query.proto  |   4 +-
 .../ibc/applications/transfer/v2/token.proto  |   7 +-
 11 files changed, 182 insertions(+), 182 deletions(-)

diff --git a/modules/apps/transfer/internal/convert/convert.go b/modules/apps/transfer/internal/convert/convert.go
index 5dd36afa4f6..cc46f7d6e73 100644
--- a/modules/apps/transfer/internal/convert/convert.go
+++ b/modules/apps/transfer/internal/convert/convert.go
@@ -34,7 +34,7 @@ func PacketDataV1ToV2(packetData types.FungibleTokenPacketData) (types.FungibleT
 }
 
 // extractDenomAndTraceFromV1Denom extracts the base denom and remaining trace from a v1 IBC denom.
-func ExtractDenomAndTraceFromV1Denom(v1Denom string) (string, []string) {
+func ExtractDenomAndTraceFromV1Denom(v1Denom string) (string, []types.Trace) {
 	v1DenomTrace := types.ParseDenomTrace(v1Denom)
 
 	// if the path string is empty, then the base denom is the full native denom.
@@ -51,9 +51,9 @@ func ExtractDenomAndTraceFromV1Denom(v1Denom string) (string, []string) {
 
 	// the path slices consists of entries of ports and channel ids separately,
 	// we need to combine them to form the trace.
-	var trace []string
+	var trace []types.Trace
 	for i := 0; i < len(splitPath); i += 2 {
-		trace = append(trace, strings.Join(splitPath[i:i+2], "/"))
+		trace = append(trace, types.NewTrace(splitPath[i], splitPath[i+1]))
 	}
 
 	return v1DenomTrace.BaseDenom, trace
diff --git a/modules/apps/transfer/internal/convert/convert_test.go b/modules/apps/transfer/internal/convert/convert_test.go
index fa289c32d7f..73f80c75cd4 100644
--- a/modules/apps/transfer/internal/convert/convert_test.go
+++ b/modules/apps/transfer/internal/convert/convert_test.go
@@ -29,8 +29,10 @@ func TestConvertPacketV1ToPacketV2(t *testing.T) {
 				[]types.Token{
 					{
 						Denom: types.Denom{
-							Base:  "atom",
-							Trace: []string{"transfer/channel-0"},
+							Base: "atom",
+							Trace: []types.Trace{
+								types.NewTrace("transfer", "channel-0"),
+							},
 						},
 						Amount: "1000",
 					},
@@ -59,8 +61,10 @@ func TestConvertPacketV1ToPacketV2(t *testing.T) {
 				[]types.Token{
 					{
 						Denom: types.Denom{
-							Base:  "atom/withslash",
-							Trace: []string{"transfer/channel-0"},
+							Base: "atom/withslash",
+							Trace: []types.Trace{
+								types.NewTrace("transfer", "channel-0"),
+							},
 						},
 						Amount: "1000",
 					},
@@ -74,8 +78,10 @@ func TestConvertPacketV1ToPacketV2(t *testing.T) {
 				[]types.Token{
 					{
 						Denom: types.Denom{
-							Base:  "atom/",
-							Trace: []string{"transfer/channel-0"},
+							Base: "atom/",
+							Trace: []types.Trace{
+								types.NewTrace("transfer", "channel-0"),
+							},
 						},
 						Amount: "1000",
 					},
@@ -89,8 +95,11 @@ func TestConvertPacketV1ToPacketV2(t *testing.T) {
 				[]types.Token{
 					{
 						Denom: types.Denom{
-							Base:  "atom/pool",
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Base: "atom/pool",
+							Trace: []types.Trace{
+								types.NewTrace("transfer", "channel-0"),
+								types.NewTrace("transfer", "channel-1"),
+							},
 						},
 						Amount: "1000",
 					},
@@ -104,8 +113,12 @@ func TestConvertPacketV1ToPacketV2(t *testing.T) {
 				[]types.Token{
 					{
 						Denom: types.Denom{
-							Base:  "atom",
-							Trace: []string{"transfer/channel-0", "transfer/channel-1", "transfer-custom/channel-2"},
+							Base: "atom",
+							Trace: []types.Trace{
+								types.NewTrace("transfer", "channel-0"),
+								types.NewTrace("transfer", "channel-1"),
+								types.NewTrace("transfer-custom", "channel-2"),
+							},
 						},
 						Amount: "1000",
 					},
@@ -119,8 +132,12 @@ func TestConvertPacketV1ToPacketV2(t *testing.T) {
 				[]types.Token{
 					{
 						Denom: types.Denom{
-							Base:  "atom/pool",
-							Trace: []string{"transfer/channel-0", "transfer/channel-1", "transfer-custom/channel-2"},
+							Base: "atom/pool",
+							Trace: []types.Trace{
+								types.NewTrace("transfer", "channel-0"),
+								types.NewTrace("transfer", "channel-1"),
+								types.NewTrace("transfer-custom", "channel-2"),
+							},
 						},
 						Amount: "1000",
 					},
diff --git a/modules/apps/transfer/keeper/relay.go b/modules/apps/transfer/keeper/relay.go
index 869f62b89df..e1e27c66676 100644
--- a/modules/apps/transfer/keeper/relay.go
+++ b/modules/apps/transfer/keeper/relay.go
@@ -141,7 +141,7 @@ func (k Keeper) sendTransfer(
 				telemetry.SetGaugeWithLabels(
 					[]string{"tx", "msg", "ibc", "transfer"},
 					float32(amount.Int64()),
-					[]metrics.Label{telemetry.NewLabel(coretypes.LabelDenom, token.GetFullDenomPath())},
+					[]metrics.Label{telemetry.NewLabel(coretypes.LabelDenom, token.Denom.FullPath())},
 				)
 			}
 		}
@@ -239,7 +239,7 @@ func (k Keeper) OnRecvPacket(ctx sdk.Context, packet channeltypes.Packet, data t
 		// sender chain is the source, mint vouchers
 
 		// since SendPacket did not prefix the denomination, we must add the destination port and channel to the trace
-		trace := []string{fmt.Sprintf("%s/%s", packet.DestinationPort, packet.DestinationChannel)}
+		trace := []types.Trace{types.NewTrace(packet.DestinationPort, packet.DestinationChannel)}
 		token.Denom.Trace = append(trace, token.Denom.Trace...)
 
 		if !k.HasDenom(ctx, token.Denom.Hash()) {
diff --git a/modules/apps/transfer/types/denom.go b/modules/apps/transfer/types/denom.go
index 482eac10e24..160bff16f96 100644
--- a/modules/apps/transfer/types/denom.go
+++ b/modules/apps/transfer/types/denom.go
@@ -16,15 +16,12 @@ func (d Denom) Validate() error {
 	// NOTE: base denom validation cannot be performed as each chain may define
 	// its own base denom validation
 	if strings.TrimSpace(d.Base) == "" {
-		return fmt.Errorf("base denomination cannot be blank")
+		return errorsmod.Wrap(ErrInvalidDenomForTransfer, "base denomination cannot be blank")
 	}
 
-	if len(d.Trace) != 0 {
-		trace := strings.Join(d.Trace, "/")
-		identifiers := strings.Split(trace, "/")
-
-		if err := validateTraceIdentifiers(identifiers); err != nil {
-			return err
+	for _, trace := range d.Trace {
+		if err := trace.Validate(); err != nil {
+			return errorsmod.Wrap(err, "invalid trace")
 		}
 	}
 
@@ -59,8 +56,8 @@ func (d Denom) FullPath() string {
 
 	var sb strings.Builder
 	for _, t := range d.Trace {
-		sb.WriteString(t) // nolint:revive // no error returned by WriteString
-		sb.WriteByte('/') //nolint:revive // no error returned by WriteByte
+		sb.WriteString(t.String()) // nolint:revive // no error returned by WriteString
+		sb.WriteByte('/')          //nolint:revive // no error returned by WriteByte
 	}
 	sb.WriteString(d.Base) //nolint:revive
 	return sb.String()
@@ -74,24 +71,21 @@ func (d Denom) IsNative() bool {
 // SenderChainIsSource returns false if the denomination originally came
 // from the receiving chain and true otherwise.
 func (d Denom) SenderChainIsSource(sourcePort, sourceChannel string) bool {
-	// This is the prefix that would have been prefixed to the denomination
-	// on sender chain IF and only if the token originally came from the
-	// receiving chain.
-
+	// sender chain is source, if the receiver is not source
 	return !d.ReceiverChainIsSource(sourcePort, sourceChannel)
 }
 
 // ReceiverChainIsSource returns true if the denomination originally came
 // from the receiving chain and false otherwise.
 func (d Denom) ReceiverChainIsSource(sourcePort, sourceChannel string) bool {
-	// The first element in the Denom's trace should contain the SourcePort and SourceChannel.
-	// If the receiver chain originally sent the token to the sender chain, the first element of
-	// the denom's trace will contain the sender's SourcePort and SourceChannel.
+	// if the denom is native, then the receiver chain cannot be source
 	if d.IsNative() {
 		return false
 	}
 
-	return d.Trace[0] == sourcePort+"/"+sourceChannel
+	// if the receiver chain originally sent the token to the sender chain, then the first element of
+	// the denom's trace (latest trace) will contain the SourcePort and SourceChannel.
+	return d.Trace[0].PortId == sourcePort && d.Trace[0].ChannelId == sourceChannel
 }
 
 // Denoms defines a wrapper type for a slice of Denom.
diff --git a/modules/apps/transfer/types/query.pb.go b/modules/apps/transfer/types/query.pb.go
index 0de8751b57b..b49978353ec 100644
--- a/modules/apps/transfer/types/query.pb.go
+++ b/modules/apps/transfer/types/query.pb.go
@@ -687,7 +687,7 @@ type QueryClient interface {
 	// Deprecated: Please use the Denoms endpoint instead.
 	DenomTraces(ctx context.Context, in *QueryDenomTracesRequest, opts ...grpc.CallOption) (*QueryDenomTracesResponse, error)
 	// DenomTrace queries a denomination trace information.
-	// Deprecated: Please se the Denom endpoint instead.
+	// Deprecated: Please see the Denom endpoint instead.
 	DenomTrace(ctx context.Context, in *QueryDenomTraceRequest, opts ...grpc.CallOption) (*QueryDenomTraceResponse, error)
 	// Params queries all parameters of the ibc-transfer module.
 	Params(ctx context.Context, in *QueryParamsRequest, opts ...grpc.CallOption) (*QueryParamsResponse, error)
@@ -769,7 +769,7 @@ type QueryServer interface {
 	// Deprecated: Please use the Denoms endpoint instead.
 	DenomTraces(context.Context, *QueryDenomTracesRequest) (*QueryDenomTracesResponse, error)
 	// DenomTrace queries a denomination trace information.
-	// Deprecated: Please se the Denom endpoint instead.
+	// Deprecated: Please see the Denom endpoint instead.
 	DenomTrace(context.Context, *QueryDenomTraceRequest) (*QueryDenomTraceResponse, error)
 	// Params queries all parameters of the ibc-transfer module.
 	Params(context.Context, *QueryParamsRequest) (*QueryParamsResponse, error)
diff --git a/modules/apps/transfer/types/token.go b/modules/apps/transfer/types/token.go
index be8d30808ca..0b826929d0f 100644
--- a/modules/apps/transfer/types/token.go
+++ b/modules/apps/transfer/types/token.go
@@ -7,10 +7,10 @@ import (
 	sdkmath "cosmossdk.io/math"
 )
 
-// Validate validates a token denomination and trace identifiers.
+// Validate validates a token denomination and amount.
 func (t Token) Validate() error {
-	if strings.TrimSpace(t.Denom.Base) == "" {
-		return errorsmod.Wrap(ErrInvalidDenomForTransfer, "denom cannot be empty")
+	if err := t.Denom.Validate(); err != nil {
+		return errorsmod.Wrap(err, "invalid token denom")
 	}
 
 	amount, ok := sdkmath.NewIntFromString(t.Amount)
@@ -22,29 +22,9 @@ func (t Token) Validate() error {
 		return errorsmod.Wrapf(ErrInvalidAmount, "amount must be strictly positive: got %d", amount)
 	}
 
-	if len(t.Denom.Trace) != 0 {
-		trace := strings.Join(t.Denom.Trace, "/")
-		identifiers := strings.Split(trace, "/")
-
-		if err := validateTraceIdentifiers(identifiers); err != nil {
-			return err
-		}
-	}
-
 	return nil
 }
 
-// GetFullDenomPath returns the full denomination according to the ICS20 specification:
-// tracePath + "/" + baseDenom
-// If there exists no trace then the base denomination is returned.
-func (t Token) GetFullDenomPath() string {
-	if len(t.Denom.Trace) == 0 {
-		return t.Denom.Base
-	}
-
-	return strings.Join(append(t.Denom.Trace, t.Denom.Base), "/")
-}
-
 // Tokens is a set of Token
 type Tokens []Token
 
diff --git a/modules/apps/transfer/types/token.pb.go b/modules/apps/transfer/types/token.pb.go
index ec174e99138..82789c743c3 100644
--- a/modules/apps/transfer/types/token.pb.go
+++ b/modules/apps/transfer/types/token.pb.go
@@ -83,7 +83,7 @@ type Denom struct {
 	// the base token denomination
 	Base string `protobuf:"bytes,1,opt,name=base,proto3" json:"base,omitempty"`
 	// the trace of the token
-	Trace []string `protobuf:"bytes,3,rep,name=trace,proto3" json:"trace,omitempty"`
+	Trace []Trace `protobuf:"bytes,3,rep,name=trace,proto3" json:"trace"`
 }
 
 func (m *Denom) Reset()         { *m = Denom{} }
@@ -126,7 +126,7 @@ func (m *Denom) GetBase() string {
 	return ""
 }
 
-func (m *Denom) GetTrace() []string {
+func (m *Denom) GetTrace() []Trace {
 	if m != nil {
 		return m.Trace
 	}
@@ -141,9 +141,8 @@ type Trace struct {
 	ChannelId string `protobuf:"bytes,2,opt,name=channel_id,json=channelId,proto3" json:"channel_id,omitempty"`
 }
 
-func (m *Trace) Reset()         { *m = Trace{} }
-func (m *Trace) String() string { return proto.CompactTextString(m) }
-func (*Trace) ProtoMessage()    {}
+func (m *Trace) Reset()      { *m = Trace{} }
+func (*Trace) ProtoMessage() {}
 func (*Trace) Descriptor() ([]byte, []int) {
 	return fileDescriptor_732b93aa1330663e, []int{2}
 }
@@ -199,26 +198,27 @@ func init() {
 }
 
 var fileDescriptor_732b93aa1330663e = []byte{
-	// 303 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x7c, 0x90, 0xb1, 0x4e, 0xc3, 0x30,
-	0x18, 0x84, 0x13, 0xda, 0x14, 0xc5, 0x6c, 0x56, 0x05, 0x15, 0x02, 0x53, 0x95, 0x25, 0x0b, 0xb6,
-	0x28, 0x03, 0x6c, 0x95, 0x2a, 0x96, 0x8e, 0x44, 0x9d, 0x58, 0xc0, 0x76, 0x4c, 0x6a, 0xd1, 0xf8,
-	0x8f, 0x62, 0xb7, 0x12, 0x6f, 0xc1, 0x63, 0x75, 0xec, 0xc8, 0x84, 0x50, 0xfb, 0x22, 0xc8, 0x49,
-	0x90, 0x3a, 0xb1, 0xdd, 0xd9, 0xdf, 0xfd, 0x27, 0x1d, 0x4a, 0xb4, 0x90, 0x8c, 0x97, 0xe5, 0x52,
-	0x4b, 0xee, 0x34, 0x18, 0xcb, 0x5c, 0xc5, 0x8d, 0x7d, 0x53, 0x15, 0x5b, 0x8f, 0x99, 0x83, 0x77,
-	0x65, 0x68, 0x59, 0x81, 0x03, 0x7c, 0xa1, 0x85, 0xa4, 0x87, 0x24, 0xfd, 0x23, 0xe9, 0x7a, 0x7c,
-	0xde, 0xcf, 0x21, 0x87, 0x1a, 0x64, 0x5e, 0x35, 0x99, 0xd1, 0x2b, 0x8a, 0xe6, 0xfe, 0x04, 0x9e,
-	0xa0, 0x28, 0x53, 0x06, 0x8a, 0x41, 0x38, 0x0c, 0x93, 0x93, 0xf1, 0x35, 0xfd, 0xef, 0x18, 0x7d,
-	0xf4, 0xe8, 0xb4, 0xbb, 0xf9, 0xbe, 0x0a, 0xd2, 0x26, 0x87, 0x4f, 0x51, 0x8f, 0x17, 0xb0, 0x32,
-	0x6e, 0x70, 0x34, 0x0c, 0x93, 0x38, 0x6d, 0xdd, 0xe8, 0x16, 0x45, 0x35, 0x8d, 0x31, 0xea, 0x0a,
-	0x6e, 0x55, 0x5d, 0x10, 0xa7, 0xb5, 0xc6, 0x7d, 0x14, 0xb9, 0x8a, 0x4b, 0x35, 0xe8, 0x0c, 0x3b,
-	0x49, 0x9c, 0x36, 0x66, 0x34, 0x41, 0xd1, 0xdc, 0x0b, 0x7c, 0x86, 0x8e, 0x4b, 0xa8, 0xdc, 0x8b,
-	0xce, 0xda, 0x54, 0xcf, 0xdb, 0x59, 0x86, 0x2f, 0x11, 0x92, 0x0b, 0x6e, 0x8c, 0x5a, 0xfa, 0xbf,
-	0xa6, 0x30, 0x6e, 0x5f, 0x66, 0xd9, 0xf4, 0x69, 0xb3, 0x23, 0xe1, 0x76, 0x47, 0xc2, 0x9f, 0x1d,
-	0x09, 0x3f, 0xf7, 0x24, 0xd8, 0xee, 0x49, 0xf0, 0xb5, 0x27, 0xc1, 0xf3, 0x7d, 0xae, 0xdd, 0x62,
-	0x25, 0xa8, 0x84, 0x82, 0x49, 0xb0, 0x05, 0x58, 0xa6, 0x85, 0xbc, 0xc9, 0x81, 0xad, 0x1f, 0x58,
-	0x01, 0xd9, 0x6a, 0xa9, 0xac, 0x5f, 0xfb, 0x60, 0x65, 0xf7, 0x51, 0x2a, 0x2b, 0x7a, 0xf5, 0x5e,
-	0x77, 0xbf, 0x01, 0x00, 0x00, 0xff, 0xff, 0x7e, 0xb8, 0x68, 0x44, 0x8f, 0x01, 0x00, 0x00,
+	// 319 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x84, 0x91, 0xb1, 0x4b, 0x3b, 0x31,
+	0x14, 0xc7, 0xef, 0x7e, 0xed, 0xf5, 0x47, 0xe3, 0x16, 0x44, 0x8b, 0x68, 0x5a, 0xea, 0xd2, 0xc5,
+	0x04, 0xea, 0xa0, 0xb8, 0x08, 0x45, 0x87, 0x8e, 0x96, 0x4e, 0x22, 0x68, 0x92, 0x8b, 0xd7, 0x60,
+	0x2f, 0xef, 0xb8, 0xa4, 0x05, 0xff, 0x0b, 0x47, 0x47, 0xff, 0x9c, 0x8e, 0x1d, 0x9d, 0x44, 0xda,
+	0x7f, 0x44, 0x92, 0x5e, 0xa1, 0x93, 0x6e, 0xef, 0xbd, 0xfb, 0x7c, 0xdf, 0xe7, 0xc8, 0x43, 0x3d,
+	0x2d, 0x24, 0xe3, 0x45, 0x31, 0xd5, 0x92, 0x3b, 0x0d, 0xc6, 0x32, 0x57, 0x72, 0x63, 0x9f, 0x55,
+	0xc9, 0xe6, 0x7d, 0xe6, 0xe0, 0x45, 0x19, 0x5a, 0x94, 0xe0, 0x00, 0x1f, 0x6b, 0x21, 0xe9, 0x2e,
+	0x49, 0xb7, 0x24, 0x9d, 0xf7, 0x8f, 0xf6, 0x33, 0xc8, 0x20, 0x80, 0xcc, 0x57, 0x9b, 0x4c, 0xf7,
+	0x09, 0x25, 0x63, 0xbf, 0x02, 0x5f, 0xa3, 0x24, 0x55, 0x06, 0xf2, 0x56, 0xdc, 0x89, 0x7b, 0x7b,
+	0xfd, 0x53, 0xfa, 0xdb, 0x32, 0x7a, 0xe3, 0xd1, 0x41, 0x7d, 0xf1, 0xd5, 0x8e, 0x46, 0x9b, 0x1c,
+	0x3e, 0x40, 0x0d, 0x9e, 0xc3, 0xcc, 0xb8, 0xd6, 0xbf, 0x4e, 0xdc, 0x6b, 0x8e, 0xaa, 0xae, 0xfb,
+	0x80, 0x92, 0x40, 0x63, 0x8c, 0xea, 0x82, 0x5b, 0x15, 0x04, 0xcd, 0x51, 0xa8, 0xbd, 0xd5, 0x95,
+	0x5c, 0xaa, 0x56, 0xad, 0x53, 0xfb, 0xdb, 0x3a, 0xf6, 0xe8, 0xd6, 0x1a, 0x72, 0xdd, 0x5b, 0x94,
+	0x84, 0x29, 0x3e, 0x44, 0xff, 0x0b, 0x28, 0xdd, 0xa3, 0x4e, 0x2b, 0x41, 0xc3, 0xb7, 0xc3, 0x14,
+	0x9f, 0x20, 0x24, 0x27, 0xdc, 0x18, 0x35, 0xf5, 0xdf, 0x36, 0xff, 0xd6, 0xac, 0x26, 0xc3, 0xf4,
+	0xaa, 0xfe, 0xfe, 0xd1, 0x8e, 0x06, 0x77, 0x8b, 0x15, 0x89, 0x97, 0x2b, 0x12, 0x7f, 0xaf, 0x48,
+	0xfc, 0xb6, 0x26, 0xd1, 0x72, 0x4d, 0xa2, 0xcf, 0x35, 0x89, 0xee, 0x2f, 0x32, 0xed, 0x26, 0x33,
+	0x41, 0x25, 0xe4, 0x4c, 0x82, 0xcd, 0xc1, 0x32, 0x2d, 0xe4, 0x59, 0x06, 0x6c, 0x7e, 0xc9, 0x72,
+	0x48, 0x67, 0x53, 0x65, 0xfd, 0x79, 0x76, 0xce, 0xe2, 0x5e, 0x0b, 0x65, 0x45, 0x23, 0x3c, 0xf0,
+	0xf9, 0x4f, 0x00, 0x00, 0x00, 0xff, 0xff, 0xba, 0x9e, 0xff, 0x7f, 0xc0, 0x01, 0x00, 0x00,
 }
 
 func (m *Token) Marshal() (dAtA []byte, err error) {
@@ -283,9 +283,14 @@ func (m *Denom) MarshalToSizedBuffer(dAtA []byte) (int, error) {
 	_ = l
 	if len(m.Trace) > 0 {
 		for iNdEx := len(m.Trace) - 1; iNdEx >= 0; iNdEx-- {
-			i -= len(m.Trace[iNdEx])
-			copy(dAtA[i:], m.Trace[iNdEx])
-			i = encodeVarintToken(dAtA, i, uint64(len(m.Trace[iNdEx])))
+			{
+				size, err := m.Trace[iNdEx].MarshalToSizedBuffer(dAtA[:i])
+				if err != nil {
+					return 0, err
+				}
+				i -= size
+				i = encodeVarintToken(dAtA, i, uint64(size))
+			}
 			i--
 			dAtA[i] = 0x1a
 		}
@@ -374,8 +379,8 @@ func (m *Denom) Size() (n int) {
 		n += 1 + l + sovToken(uint64(l))
 	}
 	if len(m.Trace) > 0 {
-		for _, s := range m.Trace {
-			l = len(s)
+		for _, e := range m.Trace {
+			l = e.Size()
 			n += 1 + l + sovToken(uint64(l))
 		}
 	}
@@ -585,7 +590,7 @@ func (m *Denom) Unmarshal(dAtA []byte) error {
 			if wireType != 2 {
 				return fmt.Errorf("proto: wrong wireType = %d for field Trace", wireType)
 			}
-			var stringLen uint64
+			var msglen int
 			for shift := uint(0); ; shift += 7 {
 				if shift >= 64 {
 					return ErrIntOverflowToken
@@ -595,23 +600,25 @@ func (m *Denom) Unmarshal(dAtA []byte) error {
 				}
 				b := dAtA[iNdEx]
 				iNdEx++
-				stringLen |= uint64(b&0x7F) << shift
+				msglen |= int(b&0x7F) << shift
 				if b < 0x80 {
 					break
 				}
 			}
-			intStringLen := int(stringLen)
-			if intStringLen < 0 {
+			if msglen < 0 {
 				return ErrInvalidLengthToken
 			}
-			postIndex := iNdEx + intStringLen
+			postIndex := iNdEx + msglen
 			if postIndex < 0 {
 				return ErrInvalidLengthToken
 			}
 			if postIndex > l {
 				return io.ErrUnexpectedEOF
 			}
-			m.Trace = append(m.Trace, string(dAtA[iNdEx:postIndex]))
+			m.Trace = append(m.Trace, Trace{})
+			if err := m.Trace[len(m.Trace)-1].Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
 			iNdEx = postIndex
 		default:
 			iNdEx = preIndex
diff --git a/modules/apps/transfer/types/token_test.go b/modules/apps/transfer/types/token_test.go
index 871113f48e8..e9677a76508 100644
--- a/modules/apps/transfer/types/token_test.go
+++ b/modules/apps/transfer/types/token_test.go
@@ -20,58 +20,6 @@ var (
 	receiver = sdk.AccAddress("testaddr2").String()
 )
 
-func TestGetFullDenomPath(t *testing.T) {
-	testCases := []struct {
-		name       string
-		packetData FungibleTokenPacketDataV2
-		expPath    string
-	}{
-		{
-			"denom path with trace",
-			NewFungibleTokenPacketDataV2(
-				[]Token{
-					{
-						Denom: Denom{
-							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
-						},
-						Amount: amount,
-					},
-				},
-				sender,
-				receiver,
-				"",
-			),
-			"transfer/channel-0/transfer/channel-1/atom/pool",
-		},
-		{
-			"nil trace",
-			NewFungibleTokenPacketDataV2(
-				[]Token{
-					{
-						Denom: Denom{
-							Base:  denom,
-							Trace: []string{},
-						},
-						Amount: amount,
-					},
-				},
-				sender,
-				receiver,
-				"",
-			),
-			denom,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			path := tc.packetData.Tokens[0].GetFullDenomPath()
-			require.Equal(t, tc.expPath, path)
-		})
-	}
-}
-
 func TestValidate(t *testing.T) {
 	testCases := []struct {
 		name     string
@@ -82,8 +30,11 @@ func TestValidate(t *testing.T) {
 			"success: multiple port channel pair denom",
 			Token{
 				Denom: Denom{
-					Base:  "atom",
-					Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+					Base: "atom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-0"),
+						NewTrace("transfer", "channel-1"),
+					},
 				},
 				Amount: amount,
 			},
@@ -93,8 +44,10 @@ func TestValidate(t *testing.T) {
 			"success: one port channel pair denom",
 			Token{
 				Denom: Denom{
-					Base:  "uatom",
-					Trace: []string{"transfer/channel-1"},
+					Base: "uatom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-1"),
+					},
 				},
 				Amount: amount,
 			},
@@ -104,8 +57,12 @@ func TestValidate(t *testing.T) {
 			"success: non transfer port trace",
 			Token{
 				Denom: Denom{
-					Base:  "uatom",
-					Trace: []string{"transfer/channel-0", "transfer/channel-1", "transfer-custom/channel-2"},
+					Base: "uatom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-0"),
+						NewTrace("transfer", "channel-1"),
+						NewTrace("transfer-custom", "channel-2"),
+					},
 				},
 				Amount: amount,
 			},
@@ -123,8 +80,11 @@ func TestValidate(t *testing.T) {
 			"failure: invalid amount string",
 			Token{
 				Denom: Denom{
-					Base:  "atom",
-					Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+					Base: "atom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-0"),
+						NewTrace("transfer", "channel-1"),
+					},
 				},
 				Amount: "value",
 			},
@@ -134,8 +94,11 @@ func TestValidate(t *testing.T) {
 			"failure: amount is zero",
 			Token{
 				Denom: Denom{
-					Base:  "atom",
-					Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+					Base: "atom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-0"),
+						NewTrace("transfer", "channel-1"),
+					},
 				},
 				Amount: "0",
 			},
@@ -145,8 +108,11 @@ func TestValidate(t *testing.T) {
 			"failure: amount is negative",
 			Token{
 				Denom: Denom{
-					Base:  "atom",
-					Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+					Base: "atom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-0"),
+						NewTrace("transfer", "channel-1"),
+					},
 				},
 				Amount: "-1",
 			},
@@ -156,8 +122,11 @@ func TestValidate(t *testing.T) {
 			"failure: invalid identifier in trace",
 			Token{
 				Denom: Denom{
-					Base:  "uatom",
-					Trace: []string{"transfer/channel-1", "randomport"},
+					Base: "uatom",
+					Trace: []Trace{
+						NewTrace("transfer", "channel-1"),
+						NewTrace("randomport", ""),
+					},
 				},
 				Amount: amount,
 			},
@@ -168,7 +137,7 @@ func TestValidate(t *testing.T) {
 			Token{
 				Denom: Denom{
 					Base:  "uatom",
-					Trace: []string{""},
+					Trace: []Trace{Trace{}},
 				},
 				Amount: amount,
 			},
@@ -206,7 +175,7 @@ func TestTokens_String(t *testing.T) {
 				Token{
 					Denom: Denom{
 						Base:  "tree",
-						Trace: []string{},
+						Trace: []Trace{},
 					},
 					Amount: "1",
 				},
@@ -218,8 +187,10 @@ func TestTokens_String(t *testing.T) {
 			Tokens{
 				Token{
 					Denom: Denom{
-						Base:  "tree",
-						Trace: []string{"portid/channelid"},
+						Base: "tree",
+						Trace: []Trace{
+							NewTrace("portid", "channelid"),
+						},
 					},
 					Amount: "1",
 				},
@@ -231,22 +202,19 @@ func TestTokens_String(t *testing.T) {
 			Tokens{
 				Token{
 					Denom: Denom{
-						Base:  "tree",
-						Trace: []string{},
+						Base: "tree",
 					},
 					Amount: "1",
 				},
 				Token{
 					Denom: Denom{
-						Base:  "gas",
-						Trace: []string{},
+						Base: "gas",
 					},
 					Amount: "2",
 				},
 				Token{
 					Denom: Denom{
-						Base:  "mineral",
-						Trace: []string{},
+						Base: "mineral",
 					},
 					Amount: "3",
 				},
@@ -258,22 +226,26 @@ func TestTokens_String(t *testing.T) {
 			Tokens{
 				Token{
 					Denom: Denom{
-						Base:  "tree",
-						Trace: []string{},
+						Base: "tree",
 					},
 					Amount: "1",
 				},
 				Token{
 					Denom: Denom{
-						Base:  "gas",
-						Trace: []string{"portid/channelid"},
+						Base: "gas",
+						Trace: []Trace{
+							NewTrace("portid", "channelid"),
+						},
 					},
 					Amount: "2",
 				},
 				Token{
 					Denom: Denom{
-						Base:  "mineral",
-						Trace: []string{"portid/channelid", "transfer/channel-52"},
+						Base: "mineral",
+						Trace: []Trace{
+							NewTrace("portid", "channelid"),
+							NewTrace("transfer", "channel-52"),
+						},
 					},
 					Amount: "3",
 				},
diff --git a/modules/apps/transfer/types/trace.go b/modules/apps/transfer/types/trace.go
index 2d18dc0e760..44052a8f2e3 100644
--- a/modules/apps/transfer/types/trace.go
+++ b/modules/apps/transfer/types/trace.go
@@ -17,6 +17,35 @@ import (
 	host "github.com/cosmos/ibc-go/v8/modules/core/24-host"
 )
 
+// NewTrace returns a Trace type
+func NewTrace(portID, channelID string) Trace {
+	return Trace{
+		PortId:    portID,
+		ChannelId: channelID,
+	}
+}
+
+// Validate does basic validation of the trace portID and channelID.
+func (t Trace) Validate() error {
+	if err := host.PortIdentifierValidator(t.PortId); err != nil {
+		return errorsmod.Wrapf(err, "invalid portID")
+	}
+	if err := host.ChannelIdentifierValidator(t.ChannelId); err != nil {
+		return errorsmod.Wrapf(err, "invalid channelID")
+	}
+	return nil
+}
+
+// String returns the Trace the format:
+// <portID>/<channelID>
+func (t Trace) String() string {
+	var sb strings.Builder
+	sb.WriteString(t.PortId)    // nolint:revive // no error returned by WriteString
+	sb.WriteByte('/')           //nolint:revive // no error returned by WriteByte
+	sb.WriteString(t.ChannelId) // nolint:revive
+	return sb.String()
+}
+
 // ParseDenomTrace parses a string with the ibc prefix (denom trace) and the base denomination
 // into a DenomTrace type.
 //
diff --git a/proto/ibc/applications/transfer/v1/query.proto b/proto/ibc/applications/transfer/v1/query.proto
index 697df1462ff..31df879f6af 100644
--- a/proto/ibc/applications/transfer/v1/query.proto
+++ b/proto/ibc/applications/transfer/v1/query.proto
@@ -15,14 +15,14 @@ service Query {
   // DenomTraces queries all denomination traces.
   // Deprecated: Please use the Denoms endpoint instead.
   rpc DenomTraces(QueryDenomTracesRequest) returns (QueryDenomTracesResponse) {
-    option deprecated = true;
+    option deprecated            = true;
     option (google.api.http).get = "/ibc/apps/transfer/v1/denom_traces";
   }
 
   // DenomTrace queries a denomination trace information.
   // Deprecated: Please see the Denom endpoint instead.
   rpc DenomTrace(QueryDenomTraceRequest) returns (QueryDenomTraceResponse) {
-    option deprecated = true;
+    option deprecated            = true;
     option (google.api.http).get = "/ibc/apps/transfer/v1/denom_traces/{hash=**}";
   }
 
diff --git a/proto/ibc/applications/transfer/v2/token.proto b/proto/ibc/applications/transfer/v2/token.proto
index 03c54d4f2ae..3ab833fa7fc 100644
--- a/proto/ibc/applications/transfer/v2/token.proto
+++ b/proto/ibc/applications/transfer/v2/token.proto
@@ -19,13 +19,14 @@ message Denom {
   // the base token denomination
   string base = 1;
   // the trace of the token
-  repeated string trace = 3;
+  repeated Trace trace = 3 [(gogoproto.nullable) = false];
 }
 
 // Trace represents the portID and channelID the token arrived through.
 // When a token is sent to a new chain, the portID and channelID of the
 // destination chain are added to a token's trace.
 message Trace {
-  string port_id    = 1;
-  string channel_id = 2;
+  option (gogoproto.goproto_stringer) = false;
+  string port_id                      = 1;
+  string channel_id                   = 2;
 }

From 5390c3605db962894dccc572d40f779661b0366d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 11:53:35 +0200
Subject: [PATCH 2/9] fix: build

---
 modules/apps/transfer/ibc_module_test.go      | 10 ++--
 modules/apps/transfer/keeper/genesis_test.go  | 16 +++---
 .../apps/transfer/keeper/grpc_query_test.go   | 39 ++++++++------
 .../apps/transfer/keeper/mbt_relay_test.go    |  3 +-
 modules/apps/transfer/keeper/relay_test.go    | 26 ++++++----
 modules/apps/transfer/transfer_test.go        |  9 ++--
 modules/apps/transfer/types/denom_test.go     | 16 +++---
 modules/apps/transfer/types/packet.go         |  3 +-
 modules/apps/transfer/types/packet_test.go    | 51 +++++++++++--------
 modules/apps/transfer/types/trace.go          | 31 ++---------
 modules/apps/transfer/types/trace_test.go     | 31 -----------
 11 files changed, 106 insertions(+), 129 deletions(-)

diff --git a/modules/apps/transfer/ibc_module_test.go b/modules/apps/transfer/ibc_module_test.go
index be2db2c261d..49b2ac9078a 100644
--- a/modules/apps/transfer/ibc_module_test.go
+++ b/modules/apps/transfer/ibc_module_test.go
@@ -556,8 +556,10 @@ func (suite *TransferTestSuite) TestPacketDataUnmarshalerInterface() {
 					Tokens: []types.Token{
 						{
 							Denom: types.Denom{
-								Base:  "atom",
-								Trace: []string{"transfer/channel-0"},
+								Base: "atom",
+								Trace: []types.Trace{
+									types.NewTrace("transfer", "channel-0"),
+								},
 							},
 							Amount: ibctesting.TestCoin.Amount.String(),
 						},
@@ -603,7 +605,7 @@ func (suite *TransferTestSuite) TestPacketDataUnmarshalerInterface() {
 						{
 							Denom: types.Denom{
 								Base:  ibctesting.TestCoin.Denom,
-								Trace: []string{""},
+								Trace: []types.Trace{types.Trace{}},
 							},
 							Amount: ibctesting.TestCoin.Amount.String(),
 						},
@@ -615,7 +617,7 @@ func (suite *TransferTestSuite) TestPacketDataUnmarshalerInterface() {
 
 				data = initialPacketData.(types.FungibleTokenPacketDataV2).GetBytes()
 			},
-			errors.New("trace info must come in pairs of port and channel identifiers"),
+			errors.New("nvalid token denom: invalid trace: invalid portID: identifier cannot be blank: invalid identifier"),
 		},
 		{
 			"failure: invalid packet data",
diff --git a/modules/apps/transfer/keeper/genesis_test.go b/modules/apps/transfer/keeper/genesis_test.go
index 4fb809e58bb..f358dbdbc7a 100644
--- a/modules/apps/transfer/keeper/genesis_test.go
+++ b/modules/apps/transfer/keeper/genesis_test.go
@@ -11,22 +11,22 @@ import (
 )
 
 func (suite *KeeperTestSuite) TestGenesis() {
-	getTrace := func(index uint) string {
-		return fmt.Sprintf("transfer/channelToChain%d", index)
+	getTrace := func(index uint) types.Trace {
+		return types.NewTrace("transfer", fmt.Sprintf("channelToChain%d", index))
 	}
 
 	var (
 		denoms                types.Denoms
 		escrows               sdk.Coins
 		traceAndEscrowAmounts = []struct {
-			trace  []string
+			trace  []types.Trace
 			escrow string
 		}{
-			{[]string{getTrace(0)}, "10"},
-			{[]string{getTrace(1), getTrace(0)}, "100000"},
-			{[]string{getTrace(2), getTrace(1), getTrace(0)}, "10000000000"},
-			{[]string{getTrace(3), getTrace(2), getTrace(1), getTrace(0)}, "1000000000000000"},
-			{[]string{getTrace(4), getTrace(3), getTrace(2), getTrace(1), getTrace(0)}, "100000000000000000000"},
+			{[]types.Trace{getTrace(0)}, "10"},
+			{[]types.Trace{getTrace(1), getTrace(0)}, "100000"},
+			{[]types.Trace{getTrace(2), getTrace(1), getTrace(0)}, "10000000000"},
+			{[]types.Trace{getTrace(3), getTrace(2), getTrace(1), getTrace(0)}, "1000000000000000"},
+			{[]types.Trace{getTrace(4), getTrace(3), getTrace(2), getTrace(1), getTrace(0)}, "100000000000000000000"},
 		}
 	)
 
diff --git a/modules/apps/transfer/keeper/grpc_query_test.go b/modules/apps/transfer/keeper/grpc_query_test.go
index 802515e85b8..0c8a1def34f 100644
--- a/modules/apps/transfer/keeper/grpc_query_test.go
+++ b/modules/apps/transfer/keeper/grpc_query_test.go
@@ -27,9 +27,11 @@ func (suite *KeeperTestSuite) TestQueryDenom() {
 			"success: correct ibc denom",
 			func() {
 				expDenom = types.Denom{
-					Base:  "uatom",                                                //nolint:goconst
-					Trace: []string{"transfer/channelToA", "transfer/channelToB"}, //nolint:goconst
-				}
+					Base: "uatom", //nolint:goconst
+					Trace: []types.Trace{
+						types.NewTrace("transfer", "channelToA"), //nolint:goconst
+						types.NewTrace("transfer", "channelToB"), //nolint:goconst
+					}}
 				suite.chainA.GetSimApp().TransferKeeper.SetDenom(suite.chainA.GetContext(), expDenom)
 
 				req = &types.QueryDenomRequest{
@@ -42,9 +44,11 @@ func (suite *KeeperTestSuite) TestQueryDenom() {
 			"success: correct hex hash",
 			func() {
 				expDenom = types.Denom{
-					Base:  "uatom",                                                //nolint:goconst
-					Trace: []string{"transfer/channelToA", "transfer/channelToB"}, //nolint:goconst
-				}
+					Base: "uatom", //nolint:goconst
+					Trace: []types.Trace{
+						types.NewTrace("transfer", "channelToA"), //nolint:goconst
+						types.NewTrace("transfer", "channelToB"), //nolint:goconst
+					}}
 
 				suite.chainA.GetSimApp().TransferKeeper.SetDenom(suite.chainA.GetContext(), expDenom)
 
@@ -67,9 +71,11 @@ func (suite *KeeperTestSuite) TestQueryDenom() {
 			"failure: not found denom trace",
 			func() {
 				expDenom = types.Denom{
-					Base:  "uatom",                                                //nolint:goconst
-					Trace: []string{"transfer/channelToA", "transfer/channelToB"}, //nolint:goconst
-				}
+					Base: "uatom", //nolint:goconst
+					Trace: []types.Trace{
+						types.NewTrace("transfer", "channelToA"), //nolint:goconst
+						types.NewTrace("transfer", "channelToB"), //nolint:goconst
+					}}
 
 				req = &types.QueryDenomRequest{
 					Hash: expDenom.IBCDenom(),
@@ -122,8 +128,8 @@ func (suite *KeeperTestSuite) TestQueryDenoms() {
 			"success",
 			func() {
 				expDenoms = append(expDenoms, types.Denom{Base: "uatom"})
-				expDenoms = append(expDenoms, types.Denom{Base: "uatom", Trace: []string{"transfer/channelToB"}})
-				expDenoms = append(expDenoms, types.Denom{Base: "uatom", Trace: []string{"transfer/channelToA", "transfer/channelToB"}})
+				expDenoms = append(expDenoms, types.Denom{Base: "uatom", Trace: []types.Trace{types.NewTrace("transfer", "channelToB")}})
+				expDenoms = append(expDenoms, types.Denom{Base: "uatom", Trace: []types.Trace{types.NewTrace("transfer", "channelToA"), types.NewTrace("transfer", "channelToB")}})
 
 				for _, trace := range expDenoms {
 					suite.chainA.GetSimApp().TransferKeeper.SetDenom(suite.chainA.GetContext(), trace)
@@ -170,8 +176,11 @@ func (suite *KeeperTestSuite) TestQueryParams() {
 
 func (suite *KeeperTestSuite) TestQueryDenomHash() {
 	reqDenom := types.Denom{
-		Base:  "uatom",
-		Trace: []string{"transfer/channelToA", "transfer/channelToB"},
+		Base: "uatom",
+		Trace: []types.Trace{
+			types.NewTrace("transfer", "channelToA"),
+			types.NewTrace("transfer", "channelToB"),
+		},
 	}
 
 	var (
@@ -336,7 +345,7 @@ func (suite *KeeperTestSuite) TestTotalEscrowForDenom() {
 			func() {
 				denomTrace := types.Denom{
 					Base:  sdk.DefaultBondDenom,
-					Trace: []string{"transfer/channel-0"},
+					Trace: []types.Trace{types.NewTrace("transfer", "channel-0")},
 				}
 
 				suite.chainA.GetSimApp().TransferKeeper.SetDenom(suite.chainA.GetContext(), denomTrace)
@@ -355,7 +364,7 @@ func (suite *KeeperTestSuite) TestTotalEscrowForDenom() {
 			func() {
 				denomTrace := types.Denom{
 					Base:  sdk.DefaultBondDenom,
-					Trace: []string{"transfer/channel-0"},
+					Trace: []types.Trace{types.NewTrace("transfer", "channel-0")},
 				}
 
 				req = &types.QueryTotalEscrowForDenomRequest{
diff --git a/modules/apps/transfer/keeper/mbt_relay_test.go b/modules/apps/transfer/keeper/mbt_relay_test.go
index e074b408ae9..231aca98c43 100644
--- a/modules/apps/transfer/keeper/mbt_relay_test.go
+++ b/modules/apps/transfer/keeper/mbt_relay_test.go
@@ -341,8 +341,7 @@ func (suite *KeeperTestSuite) TestModelBasedRelay() {
 						panic(errors.New("MBT failed to convert sender address"))
 					}
 					registerDenomFn()
-					denomTrace := types.ParseDenomTrace(tc.packet.Data.Tokens[0].GetFullDenomPath())
-					denom := denomTrace.IBCDenom()
+					denom := tc.packet.Data.Tokens[0].Denom.IBCDenom()
 					err = sdk.ValidateDenom(denom)
 					if err == nil {
 						amount, ok := sdkmath.NewIntFromString(tc.packet.Data.Tokens[0].Amount)
diff --git a/modules/apps/transfer/keeper/relay_test.go b/modules/apps/transfer/keeper/relay_test.go
index 34ddaa54ffe..c3169a6edee 100644
--- a/modules/apps/transfer/keeper/relay_test.go
+++ b/modules/apps/transfer/keeper/relay_test.go
@@ -56,8 +56,10 @@ func (suite *KeeperTestSuite) TestSendTransfer() {
 			func() {
 				// send IBC token back to chainB
 				denom := types.Denom{
-					Base:  coin.Denom,
-					Trace: []string{path.EndpointA.ChannelConfig.PortID + "/" + path.EndpointA.ChannelID},
+					Base: coin.Denom,
+					Trace: []types.Trace{
+						types.NewTrace(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID),
+					},
 				}
 				coin = sdk.NewCoin(denom.IBCDenom(), coin.Amount)
 			},
@@ -68,8 +70,10 @@ func (suite *KeeperTestSuite) TestSendTransfer() {
 			func() {
 				// send IBC token back to chainB
 				denom := types.Denom{
-					Base:  coin.Denom,
-					Trace: []string{path.EndpointA.ChannelConfig.PortID + "/" + path.EndpointA.ChannelID},
+					Base: coin.Denom,
+					Trace: []types.Trace{
+						types.NewTrace(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID),
+					},
 				}
 				coin = sdk.NewCoin(denom.IBCDenom(), coin.Amount)
 				memo = "memo"
@@ -102,8 +106,10 @@ func (suite *KeeperTestSuite) TestSendTransfer() {
 			"failure: denom trace not found",
 			func() {
 				denom := types.Denom{
-					Base:  "randomdenom",
-					Trace: []string{path.EndpointA.ChannelConfig.PortID + "/" + path.EndpointA.ChannelID},
+					Base: "randomdenom",
+					Trace: []types.Trace{
+						types.NewTrace(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID),
+					},
 				}
 				coin = sdk.NewCoin(denom.IBCDenom(), coin.Amount)
 			},
@@ -113,8 +119,10 @@ func (suite *KeeperTestSuite) TestSendTransfer() {
 			"failure: bank send from module account failed, insufficient balance",
 			func() {
 				denom := types.Denom{
-					Base:  coin.Denom,
-					Trace: []string{path.EndpointA.ChannelConfig.PortID + "/" + path.EndpointA.ChannelID},
+					Base: coin.Denom,
+					Trace: []types.Trace{
+						types.NewTrace(path.EndpointA.ChannelConfig.PortID, path.EndpointA.ChannelID),
+					},
 				}
 				coin = sdk.NewCoin(denom.IBCDenom(), coin.Amount.Add(sdkmath.NewInt(1)))
 			},
@@ -374,7 +382,7 @@ func (suite *KeeperTestSuite) TestOnRecvPacket_ReceiverIsNotSource() {
 					{
 						Denom: types.Denom{
 							Base:  sdk.DefaultBondDenom,
-							Trace: []string{},
+							Trace: []types.Trace{},
 						},
 						Amount: amount.String(),
 					},
diff --git a/modules/apps/transfer/transfer_test.go b/modules/apps/transfer/transfer_test.go
index 3a0596d0bde..f2777e293cf 100644
--- a/modules/apps/transfer/transfer_test.go
+++ b/modules/apps/transfer/transfer_test.go
@@ -1,7 +1,6 @@
 package transfer_test
 
 import (
-	"fmt"
 	"testing"
 
 	testifysuite "github.com/stretchr/testify/suite"
@@ -71,8 +70,10 @@ func (suite *TransferTestSuite) TestHandleMsgTransfer() {
 
 	// check that voucher exists on chain B
 	denom := types.Denom{
-		Base:  sdk.DefaultBondDenom,
-		Trace: []string{fmt.Sprintf("%s/%s", packet.DestinationPort, packet.DestinationChannel)},
+		Base: sdk.DefaultBondDenom,
+		Trace: []types.Trace{
+			types.NewTrace(packet.DestinationPort, packet.DestinationChannel),
+		},
 	}
 	balance = suite.chainB.GetSimApp().BankKeeper.GetBalance(suite.chainB.GetContext(), suite.chainB.SenderAccount.GetAddress(), denom.IBCDenom())
 	coinSentFromAToB := sdk.NewCoin(denom.IBCDenom(), amount)
@@ -97,7 +98,7 @@ func (suite *TransferTestSuite) TestHandleMsgTransfer() {
 	suite.Require().NoError(err) // relay committed
 
 	// NOTE: fungible token is prefixed with the full trace in order to verify the packet commitment
-	trace := []string{fmt.Sprintf("%s/%s", pathBtoC.EndpointB.ChannelConfig.PortID, pathBtoC.EndpointB.ChannelID)}
+	trace := []types.Trace{types.NewTrace(pathBtoC.EndpointB.ChannelConfig.PortID, pathBtoC.EndpointB.ChannelID)}
 	denom.Trace = append(trace, denom.Trace...)
 
 	// check that the balance is updated on chainC
diff --git a/modules/apps/transfer/types/denom_test.go b/modules/apps/transfer/types/denom_test.go
index 785c3f2fbee..5d1f9004d1c 100644
--- a/modules/apps/transfer/types/denom_test.go
+++ b/modules/apps/transfer/types/denom_test.go
@@ -20,21 +20,21 @@ func (suite *TypesTestSuite) TestDenomsValidate() {
 		{
 			"valid multiple trace info",
 			types.Denoms{
-				{Base: "uatom", Trace: []string{"transfer/channel-1", "transfer/channel-2"}},
+				{Base: "uatom", Trace: []types.Trace{types.NewTrace("transfer", "channel-1"), types.NewTrace("transfer", "channel-2")}},
 			},
 			nil,
 		},
 		{
 			"valid multiple trace info",
 			types.Denoms{
-				{Base: "uatom", Trace: []string{"transfer/channel-1", "transfer/channel-2"}},
-				{Base: "uatom", Trace: []string{"transfer/channel-1", "transfer/channel-2"}},
+				{Base: "uatom", Trace: []types.Trace{types.NewTrace("transfer", "channel-1"), types.NewTrace("transfer", "channel-2")}},
+				{Base: "uatom", Trace: []types.Trace{types.NewTrace("transfer", "channel-1"), types.NewTrace("transfer", "channel-2")}},
 			},
 			fmt.Errorf("duplicated denomination with hash"),
 		},
 		{
 			"empty base denom with trace",
-			types.Denoms{{Base: "", Trace: []string{"transfer/channel-1"}}},
+			types.Denoms{{Base: "", Trace: []types.Trace{types.NewTrace("transfer", "channel-1")}}},
 			fmt.Errorf("base denomination cannot be blank"),
 		},
 	}
@@ -81,7 +81,7 @@ func (suite *TypesTestSuite) TestFullPath() {
 			"1 hop denom",
 			types.Denom{
 				Base:  "uatom",
-				Trace: []string{"transfer/channel-0"},
+				Trace: []types.Trace{types.NewTrace("transfer", "channel-0")},
 			},
 			"transfer/channel-0/uatom",
 		},
@@ -89,7 +89,7 @@ func (suite *TypesTestSuite) TestFullPath() {
 			"2 hop denom",
 			types.Denom{
 				Base:  "uatom",
-				Trace: []string{"transfer/channel-0", "transfer/channel-52"},
+				Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-52")},
 			},
 			"transfer/channel-0/transfer/channel-52/uatom",
 		},
@@ -97,7 +97,7 @@ func (suite *TypesTestSuite) TestFullPath() {
 			"3 hop denom",
 			types.Denom{
 				Base:  "uatom",
-				Trace: []string{"transfer/channel-0", "transfer/channel-52", "transfer/channel-52"},
+				Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-52"), types.NewTrace("transfer", "channel-52")},
 			},
 			"transfer/channel-0/transfer/channel-52/transfer/channel-52/uatom",
 		},
@@ -105,7 +105,7 @@ func (suite *TypesTestSuite) TestFullPath() {
 			"4 hop denom with base denom slashes",
 			types.Denom{
 				Base:  "other-denom/",
-				Trace: []string{"transfer/channel-0", "transfer/channel-52", "transfer/channel-52", "transfer/channel-49"},
+				Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-52"), types.NewTrace("transfer", "channel-52"), types.NewTrace("transfer", "channel-49")},
 			},
 			"transfer/channel-0/transfer/channel-52/transfer/channel-52/transfer/channel-49/other-denom/",
 		},
diff --git a/modules/apps/transfer/types/packet.go b/modules/apps/transfer/types/packet.go
index e706084d56a..3eea8d5724d 100644
--- a/modules/apps/transfer/types/packet.go
+++ b/modules/apps/transfer/types/packet.go
@@ -49,7 +49,8 @@ func (ftpd FungibleTokenPacketData) ValidateBasic() error {
 	if strings.TrimSpace(ftpd.Receiver) == "" {
 		return errorsmod.Wrap(ibcerrors.ErrInvalidAddress, "receiver address cannot be blank")
 	}
-	return ValidatePrefixedDenom(ftpd.Denom)
+	denom := ExtractDenomFromFullPath(ftpd.Denom)
+	return denom.Validate()
 }
 
 // GetBytes is a helper for serialising the packet to bytes.
diff --git a/modules/apps/transfer/types/packet_test.go b/modules/apps/transfer/types/packet_test.go
index bc80cae4061..d17206a1b24 100644
--- a/modules/apps/transfer/types/packet_test.go
+++ b/modules/apps/transfer/types/packet_test.go
@@ -27,9 +27,18 @@ func TestFungibleTokenPacketDataValidateBasic(t *testing.T) {
 		expPass    bool
 	}{
 		{"valid packet", types.NewFungibleTokenPacketData(denom, amount, sender, receiver, ""), true},
+		{"valid packet, base denom with leading slash", types.NewFungibleTokenPacketData("transfer/channel-1/uatom/", amount, sender, receiver, ""), true},
+		{"valid packet, prefixed down with '/'", types.NewFungibleTokenPacketData("transfer/channel-1/gamm/pool/1", amount, sender, receiver, ""), true},
+		{"valid packet, no prefix", types.NewFungibleTokenPacketData("/uatom", amount, sender, receiver, ""), true},
+		{"valid packet, empty identifier prefix", types.NewFungibleTokenPacketData("//uatom", amount, sender, receiver, ""), true},
+		{"valid packet, only base denom", types.NewFungibleTokenPacketData("uatom", amount, sender, receiver, ""), true},
+		{"valid packet, base denom with single '/'", types.NewFungibleTokenPacketData("erc20/0x85bcBCd7e79Ec36f4fBBDc54F90C643d921151AA", amount, sender, receiver, ""), true},
+		{"valid packet, base denom with multiple '/'", types.NewFungibleTokenPacketData("gamm/pool/1", amount, sender, receiver, ""), true},
+		{"valid packet, single trace identifier", types.NewFungibleTokenPacketData("transfer/", amount, sender, receiver, ""), true},
 		{"valid packet with memo", types.NewFungibleTokenPacketData(denom, amount, sender, receiver, "memo"), true},
 		{"valid packet with large amount", types.NewFungibleTokenPacketData(denom, largeAmount, sender, receiver, ""), true},
 		{"invalid denom", types.NewFungibleTokenPacketData("", amount, sender, receiver, ""), false},
+		{"invalid denom, invalid portID", types.NewFungibleTokenPacketData("(tranfer)/channel-1/uatom", amount, sender, receiver, ""), false},
 		{"invalid empty amount", types.NewFungibleTokenPacketData(denom, "", sender, receiver, ""), false},
 		{"invalid zero amount", types.NewFungibleTokenPacketData(denom, "0", sender, receiver, ""), false},
 		{"invalid negative amount", types.NewFungibleTokenPacketData(denom, "-1", sender, receiver, ""), false},
@@ -176,7 +185,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -194,7 +203,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -212,7 +221,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: largeAmount,
 					},
@@ -230,7 +239,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  "",
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -248,7 +257,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: "",
 					},
@@ -276,7 +285,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: "0",
 					},
@@ -294,7 +303,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: "-100",
 					},
@@ -312,7 +321,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: invalidLargeAmount,
 					},
@@ -330,7 +339,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -348,7 +357,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -366,7 +375,7 @@ func TestFungibleTokenPacketDataV2ValidateBasic(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: largeAmount,
 					},
@@ -406,7 +415,7 @@ func TestGetPacketSender(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -424,7 +433,7 @@ func TestGetPacketSender(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -457,7 +466,7 @@ func TestPacketDataProvider(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -477,7 +486,7 @@ func TestPacketDataProvider(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -497,7 +506,7 @@ func TestPacketDataProvider(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -514,7 +523,7 @@ func TestPacketDataProvider(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -531,7 +540,7 @@ func TestPacketDataProvider(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -548,7 +557,7 @@ func TestPacketDataProvider(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -581,7 +590,7 @@ func TestFungibleTokenPacketDataOmitEmpty(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
@@ -599,7 +608,7 @@ func TestFungibleTokenPacketDataOmitEmpty(t *testing.T) {
 					{
 						Denom: types.Denom{
 							Base:  denom,
-							Trace: []string{"transfer/channel-0", "transfer/channel-1"},
+							Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-1")},
 						},
 						Amount: amount,
 					},
diff --git a/modules/apps/transfer/types/trace.go b/modules/apps/transfer/types/trace.go
index 6839dc7a62b..f327d409d3e 100644
--- a/modules/apps/transfer/types/trace.go
+++ b/modules/apps/transfer/types/trace.go
@@ -58,8 +58,10 @@ func (t Trace) String() string {
 // - "uatom" => DenomTrace{Path: "", BaseDenom: "uatom"}
 func ParseDenomTrace(rawDenom string) DenomTrace {
 	denom := ExtractDenomFromFullPath(rawDenom)
+	path := denom.FullPath()
+	path = strings.TrimSuffix(path, denom.Base)
 	return DenomTrace{
-		Path:      strings.Join(denom.Trace, "/"),
+		Path:      path,
 		BaseDenom: denom.Base,
 	}
 }
@@ -108,7 +110,7 @@ func ExtractDenomFromFullPath(fullPath string) Denom {
 	}
 
 	var (
-		trace          []string
+		trace          []Trace
 		baseDenomSlice []string
 	)
 
@@ -124,7 +126,7 @@ func ExtractDenomFromFullPath(fullPath string) Denom {
 		// as an IBC denomination. The hash used to store the token internally on our chain
 		// will be the same value as the base denomination being correctly parsed.
 		if i < length-1 && length > 2 && channeltypes.IsValidChannelID(denomSplit[i+1]) {
-			trace = append(trace, denomSplit[i]+"/"+denomSplit[i+1])
+			trace = append(trace, NewTrace(denomSplit[i], denomSplit[i+1]))
 		} else {
 			baseDenomSlice = denomSplit[i:]
 			break
@@ -173,29 +175,6 @@ func (dt DenomTrace) Validate() error {
 	return validateTraceIdentifiers(identifiers)
 }
 
-// ValidatePrefixedDenom checks that the denomination for an IBC fungible token packet denom is correctly prefixed.
-// The function will return no error if the given string follows one of the two formats:
-//
-//   - Prefixed denomination: '{portIDN}/{channelIDN}/.../{portID0}/{channelID0}/baseDenom'
-//   - Unprefixed denomination: 'baseDenom'
-//
-// 'baseDenom' may or may not contain '/'s
-func ValidatePrefixedDenom(fullPath string) error {
-	denom := ExtractDenomFromFullPath(fullPath)
-	if strings.TrimSpace(denom.Base) == "" {
-		return errorsmod.Wrap(ErrInvalidDenomForTransfer, "base denomination cannot be blank")
-	}
-
-	path := strings.Join(denom.Trace, "/")
-	if len(denom.Trace) != 0 {
-		identifiers := strings.Split(path, "/")
-		return validateTraceIdentifiers(identifiers)
-
-	}
-
-	return nil
-}
-
 // validateIBCDenom validates that the given denomination is either:
 //
 //   - A valid base denomination (eg: 'uatom' or 'gamm/pool/1' as in https://github.com/cosmos/ibc-go/issues/894)
diff --git a/modules/apps/transfer/types/trace_test.go b/modules/apps/transfer/types/trace_test.go
index 40ad3037586..238a701ff5f 100644
--- a/modules/apps/transfer/types/trace_test.go
+++ b/modules/apps/transfer/types/trace_test.go
@@ -94,37 +94,6 @@ func TestDenomTrace_Validate(t *testing.T) {
 	}
 }
 
-func TestValidatePrefixedDenom(t *testing.T) {
-	testCases := []struct {
-		name     string
-		denom    string
-		expError bool
-	}{
-		{"prefixed denom", "transfer/channel-1/uatom", false},
-		{"prefixed denom with base denom with leading slash", "transfer/channel-1/uatom/", false},
-		{"prefixed denom with '/'", "transfer/channel-1/gamm/pool/1", false},
-		{"empty prefix", "/uatom", false},
-		{"empty identifiers", "//uatom", false},
-		{"base denom", "uatom", false},
-		{"base denom with single '/'", "erc20/0x85bcBCd7e79Ec36f4fBBDc54F90C643d921151AA", false},
-		{"base denom with multiple '/'s", "gamm/pool/1", false},
-		{"single trace identifier", "transfer/", false},
-		{"invalid port ID", "(transfer)/channel-1/uatom", true},
-		{"empty denom", "", true},
-	}
-
-	for _, tc := range testCases {
-		tc := tc
-
-		err := types.ValidatePrefixedDenom(tc.denom)
-		if tc.expError {
-			require.Error(t, err, tc.name)
-		} else {
-			require.NoError(t, err, tc.name)
-		}
-	}
-}
-
 func TestValidateIBCDenom(t *testing.T) {
 	testCases := []struct {
 		name     string

From 5883616c33b9f8e7bdad719f1a332b732363cad9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 12:27:08 +0200
Subject: [PATCH 3/9] fix: types test

---
 modules/apps/transfer/types/token_test.go | 8 ++++----
 modules/apps/transfer/types/trace.go      | 7 +++++--
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/modules/apps/transfer/types/token_test.go b/modules/apps/transfer/types/token_test.go
index e9677a76508..b0affe22d8b 100644
--- a/modules/apps/transfer/types/token_test.go
+++ b/modules/apps/transfer/types/token_test.go
@@ -130,7 +130,7 @@ func TestValidate(t *testing.T) {
 				},
 				Amount: amount,
 			},
-			fmt.Errorf("trace info must come in pairs of port and channel identifiers '{portID}/{channelID}', got the identifiers: [transfer channel-1 randomport]"),
+			fmt.Errorf("invalid token denom: invalid trace: invalid channelID: identifier cannot be blank: invalid identifier"),
 		},
 		{
 			"failure: empty identifier in trace",
@@ -141,7 +141,7 @@ func TestValidate(t *testing.T) {
 				},
 				Amount: amount,
 			},
-			fmt.Errorf("trace info must come in pairs of port and channel identifiers '{portID}/{channelID}', got the identifiers: "),
+			fmt.Errorf("invalid token denom: invalid trace: invalid portID: identifier cannot be blank: invalid identifier"),
 		},
 	}
 
@@ -195,7 +195,7 @@ func TestTokens_String(t *testing.T) {
 					Amount: "1",
 				},
 			},
-			`denom:<base:"tree" trace:"portid/channelid" > amount:"1" `,
+			`denom:<base:"tree" trace:<port_id:"portid" channel_id:"channelid" > > amount:"1" `,
 		},
 		{
 			"multiple tokens, no trace",
@@ -250,7 +250,7 @@ func TestTokens_String(t *testing.T) {
 					Amount: "3",
 				},
 			},
-			`denom:<base:"tree" > amount:"1" ,denom:<base:"gas" trace:"portid/channelid" > amount:"2" ,denom:<base:"mineral" trace:"portid/channelid" trace:"transfer/channel-52" > amount:"3" `,
+			`denom:<base:"tree" > amount:"1" ,denom:<base:"gas" trace:<port_id:"portid" channel_id:"channelid" > > amount:"2" ,denom:<base:"mineral" trace:<port_id:"portid" channel_id:"channelid" > trace:<port_id:"transfer" channel_id:"channel-52" > > amount:"3" `,
 		},
 	}
 
diff --git a/modules/apps/transfer/types/trace.go b/modules/apps/transfer/types/trace.go
index f327d409d3e..c9a97416354 100644
--- a/modules/apps/transfer/types/trace.go
+++ b/modules/apps/transfer/types/trace.go
@@ -58,8 +58,11 @@ func (t Trace) String() string {
 // - "uatom" => DenomTrace{Path: "", BaseDenom: "uatom"}
 func ParseDenomTrace(rawDenom string) DenomTrace {
 	denom := ExtractDenomFromFullPath(rawDenom)
-	path := denom.FullPath()
-	path = strings.TrimSuffix(path, denom.Base)
+	path := ""
+	if !denom.IsNative() {
+		path = denom.FullPath()
+		path = strings.TrimSuffix(path, "/"+denom.Base)
+	}
 	return DenomTrace{
 		Path:      path,
 		BaseDenom: denom.Base,

From ac1d484f66ad9051ebe19a2ed3ab56223b2ced3a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 12:33:40 +0200
Subject: [PATCH 4/9] fix: callbacks test

---
 modules/apps/callbacks/ibc_middleware_test.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/modules/apps/callbacks/ibc_middleware_test.go b/modules/apps/callbacks/ibc_middleware_test.go
index 98a31b79918..53687fed3c7 100644
--- a/modules/apps/callbacks/ibc_middleware_test.go
+++ b/modules/apps/callbacks/ibc_middleware_test.go
@@ -169,7 +169,7 @@ func (s *CallbacksTestSuite) TestSendPacket() {
 					{
 						Denom: transfertypes.Denom{
 							Base:  ibctesting.TestCoin.GetDenom(),
-							Trace: []string{},
+							Trace: []transfertypes.Trace{},
 						},
 						Amount: ibctesting.TestCoin.Amount.String(),
 					},
@@ -313,7 +313,7 @@ func (s *CallbacksTestSuite) TestOnAcknowledgementPacket() {
 					{
 						Denom: transfertypes.Denom{
 							Base:  ibctesting.TestCoin.GetDenom(),
-							Trace: []string{},
+							Trace: []transfertypes.Trace{},
 						},
 						Amount: ibctesting.TestCoin.Amount.String(),
 					},
@@ -648,7 +648,7 @@ func (s *CallbacksTestSuite) TestOnRecvPacket() {
 					{
 						Denom: transfertypes.Denom{
 							Base:  ibctesting.TestCoin.GetDenom(),
-							Trace: []string{},
+							Trace: []transfertypes.Trace{},
 						},
 						Amount: ibctesting.TestCoin.Amount.String(),
 					},
@@ -782,7 +782,7 @@ func (s *CallbacksTestSuite) TestWriteAcknowledgement() {
 					{
 						Denom: transfertypes.Denom{
 							Base:  ibctesting.TestCoin.GetDenom(),
-							Trace: []string{},
+							Trace: []transfertypes.Trace{},
 						},
 						Amount: ibctesting.TestCoin.Amount.String(),
 					},

From a269d93d74946dc808469afac926c66eb2a22b44 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?colin=20axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 14:55:07 +0200
Subject: [PATCH 5/9] Update modules/apps/transfer/ibc_module_test.go

Co-authored-by: DimitrisJim <d.f.hilliard@gmail.com>
---
 modules/apps/transfer/ibc_module_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/apps/transfer/ibc_module_test.go b/modules/apps/transfer/ibc_module_test.go
index 49b2ac9078a..d195a039da3 100644
--- a/modules/apps/transfer/ibc_module_test.go
+++ b/modules/apps/transfer/ibc_module_test.go
@@ -617,7 +617,7 @@ func (suite *TransferTestSuite) TestPacketDataUnmarshalerInterface() {
 
 				data = initialPacketData.(types.FungibleTokenPacketDataV2).GetBytes()
 			},
-			errors.New("nvalid token denom: invalid trace: invalid portID: identifier cannot be blank: invalid identifier"),
+			errors.New("invalid token denom: invalid trace: invalid portID: identifier cannot be blank: invalid identifier"),
 		},
 		{
 			"failure: invalid packet data",

From 67abac325d78fb0e7ee91247d4e725fd9f770847 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 15:00:25 +0200
Subject: [PATCH 6/9] review: apply suggestion

---
 modules/apps/transfer/types/trace.go | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/modules/apps/transfer/types/trace.go b/modules/apps/transfer/types/trace.go
index c9a97416354..6e2dec0848d 100644
--- a/modules/apps/transfer/types/trace.go
+++ b/modules/apps/transfer/types/trace.go
@@ -39,11 +39,7 @@ func (t Trace) Validate() error {
 // String returns the Trace the format:
 // <portID>/<channelID>
 func (t Trace) String() string {
-	var sb strings.Builder
-	sb.WriteString(t.PortId)    // nolint:revive // no error returned by WriteString
-	sb.WriteByte('/')           //nolint:revive // no error returned by WriteByte
-	sb.WriteString(t.ChannelId) // nolint:revive
-	return sb.String()
+	return fmt.Sprintf("%s/%s", t.PortId, t.ChannelId)
 }
 
 // ParseDenomTrace parses a string with the ibc prefix (denom trace) and the base denomination

From 369e9f32d34057148e57542b6229019fa7e1e02d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 15:01:50 +0200
Subject: [PATCH 7/9] lint

---
 modules/apps/transfer/ibc_module_test.go        |  2 +-
 modules/apps/transfer/keeper/grpc_query_test.go | 10 ++++++----
 modules/apps/transfer/types/token_test.go       | 10 +---------
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/modules/apps/transfer/ibc_module_test.go b/modules/apps/transfer/ibc_module_test.go
index d195a039da3..43fae9a3d2b 100644
--- a/modules/apps/transfer/ibc_module_test.go
+++ b/modules/apps/transfer/ibc_module_test.go
@@ -605,7 +605,7 @@ func (suite *TransferTestSuite) TestPacketDataUnmarshalerInterface() {
 						{
 							Denom: types.Denom{
 								Base:  ibctesting.TestCoin.Denom,
-								Trace: []types.Trace{types.Trace{}},
+								Trace: []types.Trace{{}},
 							},
 							Amount: ibctesting.TestCoin.Amount.String(),
 						},
diff --git a/modules/apps/transfer/keeper/grpc_query_test.go b/modules/apps/transfer/keeper/grpc_query_test.go
index 0c8a1def34f..516a2c2692f 100644
--- a/modules/apps/transfer/keeper/grpc_query_test.go
+++ b/modules/apps/transfer/keeper/grpc_query_test.go
@@ -31,7 +31,8 @@ func (suite *KeeperTestSuite) TestQueryDenom() {
 					Trace: []types.Trace{
 						types.NewTrace("transfer", "channelToA"), //nolint:goconst
 						types.NewTrace("transfer", "channelToB"), //nolint:goconst
-					}}
+					},
+				}
 				suite.chainA.GetSimApp().TransferKeeper.SetDenom(suite.chainA.GetContext(), expDenom)
 
 				req = &types.QueryDenomRequest{
@@ -48,8 +49,8 @@ func (suite *KeeperTestSuite) TestQueryDenom() {
 					Trace: []types.Trace{
 						types.NewTrace("transfer", "channelToA"), //nolint:goconst
 						types.NewTrace("transfer", "channelToB"), //nolint:goconst
-					}}
-
+					},
+				}
 				suite.chainA.GetSimApp().TransferKeeper.SetDenom(suite.chainA.GetContext(), expDenom)
 
 				req = &types.QueryDenomRequest{
@@ -75,7 +76,8 @@ func (suite *KeeperTestSuite) TestQueryDenom() {
 					Trace: []types.Trace{
 						types.NewTrace("transfer", "channelToA"), //nolint:goconst
 						types.NewTrace("transfer", "channelToB"), //nolint:goconst
-					}}
+					},
+				}
 
 				req = &types.QueryDenomRequest{
 					Hash: expDenom.IBCDenom(),
diff --git a/modules/apps/transfer/types/token_test.go b/modules/apps/transfer/types/token_test.go
index b0affe22d8b..e7fdc15f982 100644
--- a/modules/apps/transfer/types/token_test.go
+++ b/modules/apps/transfer/types/token_test.go
@@ -5,9 +5,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
-
-	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
-	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
 const (
@@ -15,11 +12,6 @@ const (
 	amount = "100"
 )
 
-var (
-	sender   = sdk.AccAddress(secp256k1.GenPrivKey().PubKey().Address()).String()
-	receiver = sdk.AccAddress("testaddr2").String()
-)
-
 func TestValidate(t *testing.T) {
 	testCases := []struct {
 		name     string
@@ -137,7 +129,7 @@ func TestValidate(t *testing.T) {
 			Token{
 				Denom: Denom{
 					Base:  "uatom",
-					Trace: []Trace{Trace{}},
+					Trace: []Trace{{}},
 				},
 				Amount: amount,
 			},

From 4f375307220a39ae8df7369ab286bfce4e36c5be Mon Sep 17 00:00:00 2001
From: Carlos Rodriguez <carlos@interchain.io>
Date: Thu, 30 May 2024 15:07:46 +0200
Subject: [PATCH 8/9] tiny nit

---
 modules/apps/transfer/types/trace.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/apps/transfer/types/trace.go b/modules/apps/transfer/types/trace.go
index 6e2dec0848d..01f7b3b59a0 100644
--- a/modules/apps/transfer/types/trace.go
+++ b/modules/apps/transfer/types/trace.go
@@ -36,7 +36,7 @@ func (t Trace) Validate() error {
 	return nil
 }
 
-// String returns the Trace the format:
+// String returns the Trace in the format:
 // <portID>/<channelID>
 func (t Trace) String() string {
 	return fmt.Sprintf("%s/%s", t.PortId, t.ChannelId)

From 19fdd2c75bd61de2975b1859acd6333a246ac55f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 30 May 2024 15:10:23 +0200
Subject: [PATCH 9/9] fix: tests from merging main

---
 modules/apps/transfer/types/packet_test.go | 8 --------
 modules/apps/transfer/types/trace_test.go  | 9 +++++----
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/modules/apps/transfer/types/packet_test.go b/modules/apps/transfer/types/packet_test.go
index d17206a1b24..1178d821863 100644
--- a/modules/apps/transfer/types/packet_test.go
+++ b/modules/apps/transfer/types/packet_test.go
@@ -27,14 +27,6 @@ func TestFungibleTokenPacketDataValidateBasic(t *testing.T) {
 		expPass    bool
 	}{
 		{"valid packet", types.NewFungibleTokenPacketData(denom, amount, sender, receiver, ""), true},
-		{"valid packet, base denom with leading slash", types.NewFungibleTokenPacketData("transfer/channel-1/uatom/", amount, sender, receiver, ""), true},
-		{"valid packet, prefixed down with '/'", types.NewFungibleTokenPacketData("transfer/channel-1/gamm/pool/1", amount, sender, receiver, ""), true},
-		{"valid packet, no prefix", types.NewFungibleTokenPacketData("/uatom", amount, sender, receiver, ""), true},
-		{"valid packet, empty identifier prefix", types.NewFungibleTokenPacketData("//uatom", amount, sender, receiver, ""), true},
-		{"valid packet, only base denom", types.NewFungibleTokenPacketData("uatom", amount, sender, receiver, ""), true},
-		{"valid packet, base denom with single '/'", types.NewFungibleTokenPacketData("erc20/0x85bcBCd7e79Ec36f4fBBDc54F90C643d921151AA", amount, sender, receiver, ""), true},
-		{"valid packet, base denom with multiple '/'", types.NewFungibleTokenPacketData("gamm/pool/1", amount, sender, receiver, ""), true},
-		{"valid packet, single trace identifier", types.NewFungibleTokenPacketData("transfer/", amount, sender, receiver, ""), true},
 		{"valid packet with memo", types.NewFungibleTokenPacketData(denom, amount, sender, receiver, "memo"), true},
 		{"valid packet with large amount", types.NewFungibleTokenPacketData(denom, largeAmount, sender, receiver, ""), true},
 		{"invalid denom", types.NewFungibleTokenPacketData("", amount, sender, receiver, ""), false},
diff --git a/modules/apps/transfer/types/trace_test.go b/modules/apps/transfer/types/trace_test.go
index cbe9d6a40e6..23b8950760d 100644
--- a/modules/apps/transfer/types/trace_test.go
+++ b/modules/apps/transfer/types/trace_test.go
@@ -133,10 +133,11 @@ func TestExtractDenomFromFullPath(t *testing.T) {
 		{"base denom no slashes", "atom", types.Denom{Base: "atom"}},
 		{"base denom with trailing slash", "atom/", types.Denom{Base: "atom/"}},
 		{"base denom multiple trailing slash", "foo///bar//baz/atom/", types.Denom{Base: "foo///bar//baz/atom/"}},
-		{"ibc denom one hop", "transfer/channel-0/atom", types.Denom{Base: "atom", Trace: []string{"transfer/channel-0"}}},
-		{"ibc denom one hop trailing slash", "transfer/channel-0/atom/", types.Denom{Base: "atom/", Trace: []string{"transfer/channel-0"}}},
-		{"ibc denom two hops", "transfer/channel-0/transfer/channel-60/atom", types.Denom{Base: "atom", Trace: []string{"transfer/channel-0", "transfer/channel-60"}}},
-		{"ibc denom two hops trailing slash", "transfer/channel-0/transfer/channel-60/atom/", types.Denom{Base: "atom/", Trace: []string{"transfer/channel-0", "transfer/channel-60"}}},
+		{"ibc denom one hop", "transfer/channel-0/atom", types.Denom{Base: "atom", Trace: []types.Trace{types.NewTrace("transfer", "channel-0")}}},
+		{"ibc denom one hop trailing slash", "transfer/channel-0/atom/", types.Denom{Base: "atom/", Trace: []types.Trace{types.NewTrace("transfer", "channel-0")}}},
+		{"ibc denom one hop multiple slashes", "transfer/channel-0//at/om/", types.Denom{Base: "/at/om/", Trace: []types.Trace{types.NewTrace("transfer", "channel-0")}}},
+		{"ibc denom two hops", "transfer/channel-0/transfer/channel-60/atom", types.Denom{Base: "atom", Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-60")}}},
+		{"ibc denom two hops trailing slash", "transfer/channel-0/transfer/channel-60/atom/", types.Denom{Base: "atom/", Trace: []types.Trace{types.NewTrace("transfer", "channel-0"), types.NewTrace("transfer", "channel-60")}}},
 		{"empty prefix", "/uatom", types.Denom{Base: "/uatom"}},
 		{"empty identifiers", "//uatom", types.Denom{Base: "//uatom"}},
 		{"base denom with single '/'", "erc20/0x85bcBCd7e79Ec36f4fBBDc54F90C643d921151AA", types.Denom{Base: "erc20/0x85bcBCd7e79Ec36f4fBBDc54F90C643d921151AA"}},