fix: adjust InitModule to account for empty controller and host keepe…

…rs (#1120)

## Description



closes: #XXXX

---

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checked off. If any of the checklist items are not applicable, please leave them but
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- [x] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [x] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [x] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [x] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [x] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [x] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [x] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [x] Re-reviewed `Files changed` in the Github PR explorer
- [x] Review `Codecov Report` in the comment section below once CI passes

docs/migrations/v2-to-v3.md

@@ -58,8 +58,8 @@ app.UpgradeKeeper.SetUpgradeHandler("v3",
 
 ```
 
-The host and controller submodule params only need to be set if you integrate those submodules. 
-For example, if a chain chooses not to integrate a controller submodule, it does not need to set the controller params. 
+The host and controller submodule params only need to be set if the chain integrates those submodules. 
+For example, if a chain chooses not to integrate a controller submodule, it may pass empty params into `InitModule`.
 
 #### Add `StoreUpgrades` for ICS27 module
 
@@ -76,6 +76,9 @@ if upgradeInfo.Name == "v3" && !app.UpgradeKeeper.IsSkipHeight(upgradeInfo.Heigh
 ```
 
 This ensures that the new module's stores are added to the multistore before the migrations begin. 
+The host and controller submodule keys only need to be added if the chain integrates those submodules.
+For example, if a chain chooses not to integrate a controller submodule, it does not need to add the controller key to the `Added` field.
+
 
 ### Genesis migrations
 

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

@@ -105,12 +105,17 @@ func NewAppModule(controllerKeeper *controllerkeeper.Keeper, hostKeeper *hostkee
 // InitModule will initialize the interchain accounts moudule. It should only be
 // called once and as an alternative to InitGenesis.
 func (am AppModule) InitModule(ctx sdk.Context, controllerParams controllertypes.Params, hostParams hosttypes.Params) {
-	am.controllerKeeper.SetParams(ctx, controllerParams)
-	am.hostKeeper.SetParams(ctx, hostParams)
+	if am.controllerKeeper != nil {
+		am.controllerKeeper.SetParams(ctx, controllerParams)
+	}
+
+	if am.hostKeeper != nil {
+		am.hostKeeper.SetParams(ctx, hostParams)
 
-	cap := am.hostKeeper.BindPort(ctx, types.PortID)
-	if err := am.hostKeeper.ClaimCapability(ctx, cap, ibchost.PortPath(types.PortID)); err != nil {
-		panic(fmt.Sprintf("could not claim port capability: %v", err))
+		cap := am.hostKeeper.BindPort(ctx, types.PortID)
+		if err := am.hostKeeper.ClaimCapability(ctx, cap, ibchost.PortPath(types.PortID)); err != nil {
+			panic(fmt.Sprintf("could not claim port capability: %v", err))
+		}
 	}
 }
 

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

@@ -31,8 +31,9 @@ func (suite *InterchainAccountsTestSuite) SetupTest() {
 }
 
 func (suite *InterchainAccountsTestSuite) TestInitModule() {
+	// setup and basic testing
 	app := simapp.NewSimApp(log.NewNopLogger(), dbm.NewMemDB(), nil, true, map[int64]bool{}, simapp.DefaultNodeHome, 5, simapp.MakeTestEncodingConfig(), simapp.EmptyAppOptions{})
-	icamodule, ok := app.GetModuleManager().Modules[types.ModuleName].(ica.AppModule)
+	appModule, ok := app.GetModuleManager().Modules[types.ModuleName].(ica.AppModule)
 	suite.Require().True(ok)
 
 	header := tmproto.Header{
@@ -58,17 +59,74 @@ func (suite *InterchainAccountsTestSuite) TestInitModule() {
 	expAllowMessages := []string{"sdk.Msg"}
 	hostParams.HostEnabled = true
 	hostParams.AllowMessages = expAllowMessages
-
 	suite.Require().False(app.IBCKeeper.PortKeeper.IsBound(ctx, types.PortID))
 
-	icamodule.InitModule(ctx, controllerParams, hostParams)
+	testCases := []struct {
+		name              string
+		malleate          func()
+		expControllerPass bool
+		expHostPass       bool
+	}{
+		{
+			"both controller and host set", func() {
+				var ok bool
+				appModule, ok = app.GetModuleManager().Modules[types.ModuleName].(ica.AppModule)
+				suite.Require().True(ok)
+			}, true, true,
+		},
+		{
+			"neither controller or host is set", func() {
+				appModule = ica.NewAppModule(nil, nil)
+			}, false, false,
+		},
+		{
+			"only controller is set", func() {
+				appModule = ica.NewAppModule(&app.ICAControllerKeeper, nil)
+			}, true, false,
+		},
+		{
+			"only host is set", func() {
+				appModule = ica.NewAppModule(nil, &app.ICAHostKeeper)
+			}, false, true,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+
+		suite.Run(tc.name, func() {
+			suite.SetupTest() // reset
+
+			// reset app state
+			app = simapp.NewSimApp(log.NewNopLogger(), dbm.NewMemDB(), nil, true, map[int64]bool{}, simapp.DefaultNodeHome, 5, simapp.MakeTestEncodingConfig(), simapp.EmptyAppOptions{})
+			header := tmproto.Header{
+				ChainID: "testchain",
+				Height:  1,
+				Time:    suite.coordinator.CurrentTime.UTC(),
+			}
+
+			ctx := app.GetBaseApp().NewContext(true, header)
 
-	controllerParams = app.ICAControllerKeeper.GetParams(ctx)
-	suite.Require().True(controllerParams.ControllerEnabled)
+			tc.malleate()
 
-	hostParams = app.ICAHostKeeper.GetParams(ctx)
-	suite.Require().True(hostParams.HostEnabled)
-	suite.Require().Equal(expAllowMessages, hostParams.AllowMessages)
+			suite.Require().NotPanics(func() {
+				appModule.InitModule(ctx, controllerParams, hostParams)
+			})
+
+			if tc.expControllerPass {
+				controllerParams = app.ICAControllerKeeper.GetParams(ctx)
+				suite.Require().True(controllerParams.ControllerEnabled)
+			}
+
+			if tc.expHostPass {
+				hostParams = app.ICAHostKeeper.GetParams(ctx)
+				suite.Require().True(hostParams.HostEnabled)
+				suite.Require().Equal(expAllowMessages, hostParams.AllowMessages)
+
+				suite.Require().True(app.IBCKeeper.PortKeeper.IsBound(ctx, types.PortID))
+			}
+
+		})
+	}
 
-	suite.Require().True(app.IBCKeeper.PortKeeper.IsBound(ctx, types.PortID))
 }