fix: allow version compatibility between chains upgrade from v0.8.x to v0.9.x

CHANGELOG.md

@@ -72,6 +72,7 @@ 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 genesis validation connectionID for localhost client.
+* (light-clients/09-localhost) [\#7847](https://github.com/cosmos/ibc-go/pull/7847) Add back legacy localhost RegisterInterfaces to allow version compatibility between chains upgrade from v0.8.x to v0.9.x.
 
 ## [v9.0.0](https://github.com/cosmos/ibc-go/releases/tag/v9.0.0) - 2024-10-01
 

modules/core/types/codec.go

@@ -7,6 +7,7 @@ import (
 	connectiontypes "github.com/cosmos/ibc-go/v9/modules/core/03-connection/types"
 	channeltypes "github.com/cosmos/ibc-go/v9/modules/core/04-channel/types"
 	commitmenttypes "github.com/cosmos/ibc-go/v9/modules/core/23-commitment/types"
+	localhost "github.com/cosmos/ibc-go/v9/modules/light-clients/09-localhost"
 )
 
 // RegisterInterfaces registers ibc types against interfaces using the global InterfaceRegistry.
@@ -16,4 +17,5 @@ func RegisterInterfaces(registry coreregistry.InterfaceRegistrar) {
 	connectiontypes.RegisterInterfaces(registry)
 	channeltypes.RegisterInterfaces(registry)
 	commitmenttypes.RegisterInterfaces(registry)
+	localhost.RegisterInterfaces(registry)
 }

modules/core/types/codec_test.go

@@ -0,0 +1,20 @@
+package types
+
+import (
+	"testing"
+
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	gogoprotoany "github.com/cosmos/gogoproto/types/any"
+	"github.com/cosmos/ibc-go/v9/modules/core/exported"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInterfaceRegistrationOfLocalhost(t *testing.T) {
+	registry := codectypes.NewInterfaceRegistry()
+	RegisterInterfaces(registry)
+	val := &gogoprotoany.Any{
+		TypeUrl: "/ibc.lightclients.localhost.v2.ClientState",
+		Value:   []byte{},
+	}
+	require.NoError(t, registry.UnpackAny(val, new(exported.ClientState)))
+}

modules/light-clients/09-localhost/codec.go

@@ -0,0 +1,16 @@
+package localhost
+
+import (
+	coreregistry "cosmossdk.io/core/registry"
+
+	"github.com/cosmos/ibc-go/v9/modules/core/exported"
+)
+
+// RegisterInterfaces registers the tendermint concrete client-related
+// implementations and interfaces.
+func RegisterInterfaces(registry coreregistry.InterfaceRegistrar) {
+	registry.RegisterImplementations(
+		(*exported.ClientState)(nil),
+		&ClientState{},
+	)
+}

modules/light-clients/09-localhost/localhost.go

@@ -0,0 +1,20 @@
+package localhost
+
+import (
+	errorsmod "cosmossdk.io/errors"
+	ibcerrors "github.com/cosmos/ibc-go/v9/modules/core/errors"
+	"github.com/cosmos/ibc-go/v9/modules/core/exported"
+)
+
+var _ exported.ClientState = (*ClientState)(nil)
+
+func (cs *ClientState) ClientType() string {
+	return exported.Localhost
+}
+
+func (cs *ClientState) Validate() error {
+	if cs.LatestHeight.RevisionHeight == 0 {
+		return errorsmod.Wrapf(ibcerrors.ErrInvalidHeight, "local revision height cannot be zero")
+	}
+	return nil
+}