Apply suggestions from code review

Author: mmsqe

CHANGELOG.md

@@ -64,7 +64,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * (apps/27-interchain-accounts) [\#7277](https://github.com/cosmos/ibc-go/pull/7277) Use `GogoResolver` when populating module query safe allow list to avoid panics from unresolvable protobuf dependencies.
 * (core/04-channel) [\#7342](https://github.com/cosmos/ibc-go/pull/7342) Read Tx cmd flags including from address to avoid Address cannot be empty error when upgrade-channels via cli.
-* (core/03-connection) [\#7397](https://github.com/cosmos/ibc-go/pull/7397) Skip the validation connectionID for localhost client.
+* (core/03-connection) [\#7397](https://github.com/cosmos/ibc-go/pull/7397) Skip the genesis validation connectionID for localhost client.
 
 ## [v9.0.0](https://github.com/cosmos/ibc-go/releases/tag/v9.0.0) - 2024-10-01
 

modules/core/03-connection/types/genesis.go

@@ -2,8 +2,10 @@ package types
 
 import (
 	"fmt"
+	"strings"
 
 	host "github.com/cosmos/ibc-go/v9/modules/core/24-host"
+	"github.com/cosmos/ibc-go/v9/modules/core/exported"
 )
 
 // NewConnectionPaths creates a ConnectionPaths instance.
@@ -47,6 +49,9 @@ func (gs GenesisState) Validate() error {
 	for i, conn := range gs.Connections {
 		sequence, err := ParseConnectionSequence(conn.Id)
 		if err != nil {
+			if conn.Id == exported.LocalhostConnectionID && strings.Contains(err.Error(), host.ErrInvalidID.Error()) {
+				continue
+			}
 			return err
 		}
 

modules/core/03-connection/types/genesis_test.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/cosmos/ibc-go/v9/modules/core/03-connection/types"
 	commitmenttypes "github.com/cosmos/ibc-go/v9/modules/core/23-commitment/types"
+	"github.com/cosmos/ibc-go/v9/modules/core/exported"
 	ibctesting "github.com/cosmos/ibc-go/v9/testing"
 )
 
@@ -91,6 +92,20 @@ func TestValidateGenesis(t *testing.T) {
 			),
 			expPass: false,
 		},
+		{
+			name: "localhost connection identifier",
+			genState: types.NewGenesisState(
+				[]types.IdentifiedConnection{
+					types.NewIdentifiedConnection(exported.LocalhostConnectionID, types.NewConnectionEnd(types.INIT, clientID, types.Counterparty{clientID2, connectionID2, commitmenttypes.NewMerklePrefix([]byte("prefix"))}, []*types.Version{ibctesting.ConnectionVersion}, 500)),
+				},
+				[]types.ConnectionPaths{
+					{clientID, []string{connectionID}},
+				},
+				0,
+				types.DefaultParams(),
+			),
+			expPass: true,
+		},
 		{
 			name: "next connection sequence is not greater than maximum connection identifier sequence provided",
 			genState: types.NewGenesisState(

modules/core/03-connection/types/keys.go

@@ -7,7 +7,6 @@ import (
 	errorsmod "cosmossdk.io/errors"
 
 	host "github.com/cosmos/ibc-go/v9/modules/core/24-host"
-	"github.com/cosmos/ibc-go/v9/modules/core/exported"
 )
 
 const (
@@ -53,9 +52,6 @@ func IsValidConnectionID(connectionID string) bool {
 
 // ParseConnectionSequence parses the connection sequence from the connection identifier.
 func ParseConnectionSequence(connectionID string) (uint64, error) {
-	if connectionID == exported.LocalhostConnectionID {
-		return 0, nil
-	}
 	if !IsConnectionIDFormat(connectionID) {
 		return 0, errorsmod.Wrap(host.ErrInvalidID, "connection identifier is not in the format: `connection-{N}`")
 	}

modules/core/03-connection/types/keys_test.go

@@ -30,7 +30,6 @@ func TestParseConnectionSequence(t *testing.T) {
 		{"blank id", "               ", 0, false},
 		{"empty id", "", 0, false},
 		{"negative sequence", "connection--1", 0, false},
-		{"localhost", "connection-localhost", 0, true},
 	}
 
 	for _, tc := range testCases {