chore: add ParseKeyFeesInEscrow helper function (#998)

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

@@ -335,18 +335,15 @@ func (k Keeper) GetAllIdentifiedPacketFees(ctx sdk.Context) []types.IdentifiedPa
 
 	var identifiedFees []types.IdentifiedPacketFees
 	for ; iterator.Valid(); iterator.Next() {
-		keySplit := strings.Split(string(iterator.Key()), "/")
-
-		feesInEscrow := k.MustUnmarshalFees(iterator.Value())
-
-		channelID, portID := keySplit[2], keySplit[1]
-		seq, err := strconv.ParseUint(keySplit[3], 10, 64)
+		packetID, err := types.ParseKeyFeesInEscrow(string(iterator.Key()))
 		if err != nil {
 			panic(err)
 		}
 
+		feesInEscrow := k.MustUnmarshalFees(iterator.Value())
+
 		identifiedFee := types.IdentifiedPacketFees{
-			PacketId:   channeltypes.NewPacketId(channelID, portID, seq),
+			PacketId:   packetID,
 			PacketFees: feesInEscrow.PacketFees,
 		}
 

modules/apps/29-fee/types/keys.go

@@ -2,6 +2,10 @@ package types
 
 import (
 	"fmt"
+	"strconv"
+	"strings"
+
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 
 	channeltypes "github.com/cosmos/ibc-go/v3/modules/core/04-channel/types"
 )
@@ -67,6 +71,24 @@ func KeyFeesInEscrow(packetID channeltypes.PacketId) []byte {
 	return []byte(fmt.Sprintf("%s/%d", KeyFeesInEscrowChannelPrefix(packetID.PortId, packetID.ChannelId), packetID.Sequence))
 }
 
+// ParseKeyFeesInEscrow parses the key used to store fees in escrow and returns the packet id
+func ParseKeyFeesInEscrow(key string) (channeltypes.PacketId, error) {
+	keySplit := strings.Split(key, "/")
+	if len(keySplit) != 4 {
+		return channeltypes.PacketId{}, sdkerrors.Wrapf(
+			sdkerrors.ErrLogic, "key provided is incorrect: the key split has incorrect length, expected %d, got %d", 4, len(keySplit),
+		)
+	}
+
+	seq, err := strconv.ParseUint(keySplit[3], 10, 64)
+	if err != nil {
+		return channeltypes.PacketId{}, err
+	}
+
+	packetID := channeltypes.NewPacketId(keySplit[2], keySplit[1], seq)
+	return packetID, nil
+}
+
 // KeyFeeInEscrowChannelPrefix returns the key prefix for escrowed fees on the given channel
 func KeyFeeInEscrowChannelPrefix(portID, channelID string) []byte {
 	return []byte(fmt.Sprintf("%s/%s/%s/packet", FeeInEscrowPrefix, portID, channelID))

modules/apps/29-fee/types/keys_test.go

@@ -7,6 +7,8 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/cosmos/ibc-go/v3/modules/apps/29-fee/types"
+	channeltypes "github.com/cosmos/ibc-go/v3/modules/core/04-channel/types"
+	ibctesting "github.com/cosmos/ibc-go/v3/testing"
 )
 
 func TestKeyCounterpartyRelayer(t *testing.T) {
@@ -18,3 +20,40 @@ func TestKeyCounterpartyRelayer(t *testing.T) {
 	key := types.KeyCounterpartyRelayer(relayerAddress, channelID)
 	require.Equal(t, string(key), fmt.Sprintf("%s/%s/%s", types.CounterpartyRelayerAddressKeyPrefix, relayerAddress, channelID))
 }
+
+func TestParseKeyFeesInEscrow(t *testing.T) {
+	validPacketID := channeltypes.NewPacketId(ibctesting.FirstChannelID, ibctesting.MockFeePort, 1)
+
+	testCases := []struct {
+		name    string
+		key     string
+		expPass bool
+	}{
+		{
+			"success",
+			string(types.KeyFeesInEscrow(validPacketID)),
+			true,
+		},
+		{
+			"incorrect key - key split has incorrect length",
+			string(types.FeeEnabledKey(validPacketID.PortId, validPacketID.ChannelId)),
+			false,
+		},
+		{
+			"incorrect key - sequence cannot be parsed",
+			fmt.Sprintf("%s/%s", types.KeyFeesInEscrowChannelPrefix(validPacketID.PortId, validPacketID.ChannelId), "sequence"),
+			false,
+		},
+	}
+
+	for _, tc := range testCases {
+		packetId, err := types.ParseKeyFeesInEscrow(tc.key)
+
+		if tc.expPass {
+			require.NoError(t, err)
+			require.Equal(t, validPacketID, packetId)
+		} else {
+			require.Error(t, err)
+		}
+	}
+}