fix: add nil checks for controller and host keeper services

CHANGELOG.md

@@ -72,6 +72,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (27-interchain-accounts) [\#2308](https://github.com/cosmos/ibc-go/pull/2308) Nil checks have been added to ensure services are not registered for nil host or controller keepers.
 * (27-interchain-accounts) [\#1352](https://github.com/cosmos/ibc-go/issues/1352) Add support for Cosmos-SDK simulation to ics27 module.
 * (linting) [\#1418](https://github.com/cosmos/ibc-go/pull/1418) Fix linting errors, resulting compatiblity with go1.18 linting style, golangci-lint 1.46.2 and the revivie linter.  This caused breaking changes in core/04-channel, core/ante, and the testing library.
 * (modules/light-clients/07-tendermint) [\#1713](https://github.com/cosmos/ibc-go/pull/1713) Allow client upgrade proposals to update `TrustingPeriod`. See ADR-026 for context.

modules/apps/27-interchain-accounts/controller/keeper/migrations.go

@@ -22,19 +22,21 @@ func NewMigrator(keeper *Keeper) Migrator {
 // AssertChannelCapabilityMigrations checks that all channel capabilities generated using the interchain accounts controller port prefix
 // are owned by the controller submodule and ibc.
 func (m Migrator) AssertChannelCapabilityMigrations(ctx sdk.Context) error {
-	for _, ch := range m.keeper.GetAllActiveChannels(ctx) {
-		name := host.ChannelCapabilityPath(ch.PortId, ch.ChannelId)
-		cap, found := m.keeper.scopedKeeper.GetCapability(ctx, name)
-		if !found {
-			return sdkerrors.Wrapf(capabilitytypes.ErrCapabilityNotFound, "failed to find capability: %s", name)
+	if m.keeper != nil {
+		for _, ch := range m.keeper.GetAllActiveChannels(ctx) {
+			name := host.ChannelCapabilityPath(ch.PortId, ch.ChannelId)
+			cap, found := m.keeper.scopedKeeper.GetCapability(ctx, name)
+			if !found {
+				return sdkerrors.Wrapf(capabilitytypes.ErrCapabilityNotFound, "failed to find capability: %s", name)
+			}
+
+			isAuthenticated := m.keeper.scopedKeeper.AuthenticateCapability(ctx, cap, name)
+			if !isAuthenticated {
+				return sdkerrors.Wrapf(capabilitytypes.ErrCapabilityNotOwned, "expected capability owner: %s", types.SubModuleName)
+			}
+
+			m.keeper.SetMiddlewareEnabled(ctx, ch.PortId, ch.ChannelId)
 		}
-
-		isAuthenticated := m.keeper.scopedKeeper.AuthenticateCapability(ctx, cap, name)
-		if !isAuthenticated {
-			return sdkerrors.Wrapf(capabilitytypes.ErrCapabilityNotOwned, "expected capability owner: %s", types.SubModuleName)
-		}
-
-		m.keeper.SetMiddlewareEnabled(ctx, ch.PortId, ch.ChannelId)
 	}
 
 	return nil

modules/apps/27-interchain-accounts/module.go

@@ -76,6 +76,7 @@ func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *r
 	if err != nil {
 		panic(err)
 	}
+
 	err = hosttypes.RegisterQueryHandlerClient(context.Background(), mux, hosttypes.NewQueryClient(clientCtx))
 	if err != nil {
 		panic(err)
@@ -150,9 +151,14 @@ func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sd
 
 // RegisterServices registers module services
 func (am AppModule) RegisterServices(cfg module.Configurator) {
-	controllertypes.RegisterMsgServer(cfg.MsgServer(), controllerkeeper.NewMsgServerImpl(am.controllerKeeper))
-	controllertypes.RegisterQueryServer(cfg.QueryServer(), am.controllerKeeper)
-	hosttypes.RegisterQueryServer(cfg.QueryServer(), am.hostKeeper)
+	if am.controllerKeeper != nil {
+		controllertypes.RegisterMsgServer(cfg.MsgServer(), controllerkeeper.NewMsgServerImpl(am.controllerKeeper))
+		controllertypes.RegisterQueryServer(cfg.QueryServer(), am.controllerKeeper)
+	}
+
+	if am.hostKeeper != nil {
+		hosttypes.RegisterQueryServer(cfg.QueryServer(), am.hostKeeper)
+	}
 
 	m := controllerkeeper.NewMigrator(am.controllerKeeper)
 	if err := cfg.RegisterMigration(types.ModuleName, 1, m.AssertChannelCapabilityMigrations); err != nil {