feat: Add a function to initialize the ICS27 module via an upgrade pr…

…oposal (cosmos#1037)

## Description



closes: cosmos#1034 

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [ ] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

CHANGELOG.md

@@ -64,6 +64,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (interchain-accounts) [\#1037](https://github.com/cosmos/ibc-go/pull/1037) Add a function `InitModule` to the interchain accounts `AppModule`. This function should be called within the upgrade handler when adding the interchain accounts module to a chain. It should be called in place of InitGenesis (set the consensus version in the version map).
 * (testing) [\#942](https://github.com/cosmos/ibc-go/pull/942) `NewTestChain` will create 4 validators in validator set by default. A new constructor function `NewTestChainWithValSet` is provided for test writers who want custom control over the validator set of test chains.
 * (testing) [\#904](https://github.com/cosmos/ibc-go/pull/904) Add `ParsePacketFromEvents` function to the testing package. Useful when sending/relaying packets via the testing package.
 * (testing) [\#893](https://github.com/cosmos/ibc-go/pull/893) Support custom private keys for testing.

docs/migrations/v2-to-v3.md

@@ -33,17 +33,24 @@ Please see the [ICS27 documentation](../apps/interchain-accounts/overview.md) fo
 If the chain will adopt ICS27, it must set the appropriate params during the execution of the upgrade handler in `app.go`: 
 ```go
 app.UpgradeKeeper.SetUpgradeHandler("v3",
-    func(ctx sdk.Context, _ upgradetypes.Plan, vm module.VersionMap) (module.VersionMap, error) {
-        // set ICS27 Host submodule params
-        app.ICAHostKeeper.SetParams(ctx, icahosttypes.Params{
-            HostEnabled: true, 
-            AllowMessages: []string{"/cosmos.bank.v1beta1.MsgSend", ...], 
-        })
+    func(ctx sdk.Context, _ upgradetypes.Plan, fromVM module.VersionMap) (module.VersionMap, error) {
+        // set the ICS27 consensus version so InitGenesis is not run
+        fromVM[icatypes.ModuleName] = icamodule.ConsensusVersion()
 
-        // set ICS27 Controller submodule params
-        app.ICAControllerKeeper.SetParams(ctx, icacontrollertypes.Params{
+
+        // create ICS27 Controller submodule params
+        controllerParams := icacontrollertypes.Params{
             ControllerEnabled: true, 
-        })
+        }
+
+        // create ICS27 Host submodule params
+        hostParams := icahosttypes.Params{
+            HostEnabled: true, 
+            AllowMessages: []string{"/cosmos.bank.v1beta1.MsgSend", ...], 
+        }
+
+        // initialize ICS27 module
+        icamodule.InitModule(ctx, controllerParams, hostParams)
 
         ...
 

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

@@ -24,6 +24,7 @@ import (
 	hosttypes "github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts/host/types"
 	"github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts/types"
 	porttypes "github.com/cosmos/ibc-go/v3/modules/core/05-port/types"
+	ibchost "github.com/cosmos/ibc-go/v3/modules/core/24-host"
 )
 
 var (
@@ -101,6 +102,18 @@ 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)
+
+	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))
+	}
+}
+
 // RegisterInvariants implements the AppModule interface
 func (AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {
 }

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

@@ -0,0 +1,74 @@
+package ica_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/tendermint/tendermint/libs/log"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+	dbm "github.com/tendermint/tm-db"
+
+	ica "github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts"
+	controllertypes "github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts/controller/types"
+	hosttypes "github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts/host/types"
+	"github.com/cosmos/ibc-go/v3/modules/apps/27-interchain-accounts/types"
+	ibctesting "github.com/cosmos/ibc-go/v3/testing"
+	"github.com/cosmos/ibc-go/v3/testing/simapp"
+)
+
+type InterchainAccountsTestSuite struct {
+	suite.Suite
+
+	coordinator *ibctesting.Coordinator
+}
+
+func TestICATestSuite(t *testing.T) {
+	suite.Run(t, new(InterchainAccountsTestSuite))
+}
+
+func (suite *InterchainAccountsTestSuite) SetupTest() {
+	suite.coordinator = ibctesting.NewCoordinator(suite.T(), 2)
+}
+
+func (suite *InterchainAccountsTestSuite) TestInitModule() {
+	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)
+	suite.Require().True(ok)
+
+	header := tmproto.Header{
+		ChainID: "testchain",
+		Height:  1,
+		Time:    suite.coordinator.CurrentTime.UTC(),
+	}
+
+	ctx := app.GetBaseApp().NewContext(true, header)
+
+	// ensure params are not set
+	suite.Require().Panics(func() {
+		app.ICAControllerKeeper.GetParams(ctx)
+	})
+	suite.Require().Panics(func() {
+		app.ICAHostKeeper.GetParams(ctx)
+	})
+
+	controllerParams := controllertypes.DefaultParams()
+	controllerParams.ControllerEnabled = true
+
+	hostParams := hosttypes.DefaultParams()
+	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)
+
+	controllerParams = app.ICAControllerKeeper.GetParams(ctx)
+	suite.Require().True(controllerParams.ControllerEnabled)
+
+	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))
+}

testing/simapp/app.go

@@ -571,6 +571,12 @@ func (app *SimApp) ModuleAccountAddrs() map[string]bool {
 	return modAccAddrs
 }
 
+// GetModuleManager returns the app module manager
+// NOTE: used for testing purposes
+func (app *SimApp) GetModuleManager() *module.Manager {
+	return app.mm
+}
+
 // LegacyAmino returns SimApp's amino codec.
 //
 // NOTE: This is solely to be used for testing purposes as it may be desirable