added switch case to detect blank pointers in keeper (backport #2403) (…

…#2447)

* added switch case to detect blank pointers in keeper (#2403)

* added switch case to detect blank pointers in keeper

* updated changelog.md

* updated error message for keeper

* fixed switch-case; added test cases

* added function to check for empty keeper

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>
Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>
(cherry picked from commit 462ccb6)

# Conflicts:
#	CHANGELOG.md

* fix conflict

* Update CHANGELOG.md

Co-authored-by: Ali Zahid Raja <alizahidrajaa@gmail.com>
Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

CHANGELOG.md

@@ -74,6 +74,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * (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.
 * (makefile) [\#1785](https://github.com/cosmos/ibc-go/pull/1785) Fetch the correct versions of protocol buffers dependencies from tendermint, cosmos-sdk, and ics23.
+* (modules/core/keeper) [\#2403](https://github.com/cosmos/ibc-go/pull/2403) Added a function in keeper to cater for blank pointers.
 
 ## [v4.0.0](https://github.com/cosmos/ibc-go/releases/tag/v4.0.0) - 2022-08-12
 

modules/core/keeper/keeper.go

@@ -50,11 +50,10 @@ func NewKeeper(
 	}
 
 	// panic if any of the keepers passed in is empty
-	if reflect.ValueOf(stakingKeeper).IsZero() {
+	if isEmpty(stakingKeeper) {
 		panic(fmt.Errorf("cannot initialize IBC keeper: empty staking keeper"))
 	}
-
-	if reflect.ValueOf(upgradeKeeper).IsZero() {
+	if isEmpty(upgradeKeeper) {
 		panic(fmt.Errorf("cannot initialize IBC keeper: empty upgrade keeper"))
 	}
 
@@ -92,3 +91,19 @@ func (k *Keeper) SetRouter(rtr *porttypes.Router) {
 	k.Router = rtr
 	k.Router.Seal()
 }
+
+// isEmpty checks if the interface is an empty struct or a pointer pointing
+// to an empty struct
+func isEmpty(keeper interface{}) bool {
+	switch reflect.TypeOf(keeper).Kind() {
+	case reflect.Ptr:
+		if reflect.ValueOf(keeper).Elem().IsZero() {
+			return true
+		}
+	default:
+		if reflect.ValueOf(keeper).IsZero() {
+			return true
+		}
+	}
+	return false
+}

modules/core/keeper/keeper_test.go

@@ -79,21 +79,31 @@ func (suite *KeeperTestSuite) TestNewKeeper() {
 		malleate func()
 		expPass  bool
 	}{
-		{"failure: empty staking keeper", func() {
-			emptyStakingKeeper := stakingkeeper.Keeper{}
+		{"failure: empty staking keeper value", func() {
+			emptyStakingKeeperValue := stakingkeeper.Keeper{}
 
-			stakingKeeper = emptyStakingKeeper
+			stakingKeeper = emptyStakingKeeperValue
+		}, false},
+		{"failure: empty staking keeper pointer", func() {
+			emptyStakingKeeperPointer := &stakingkeeper.Keeper{}
+
+			stakingKeeper = emptyStakingKeeperPointer
 		}, false},
 		{"failure: empty mock staking keeper", func() {
 			// use a different implementation of clienttypes.StakingKeeper
 			emptyMockStakingKeeper := MockStakingKeeper{}
 
 			stakingKeeper = emptyMockStakingKeeper
 		}, false},
-		{"failure: empty upgrade keeper", func() {
-			emptyUpgradeKeeper := upgradekeeper.Keeper{}
+		{"failure: empty upgrade keeper value", func() {
+			emptyUpgradeKeeperValue := upgradekeeper.Keeper{}
+
+			upgradeKeeper = emptyUpgradeKeeperValue
+		}, false},
+		{"failure: empty upgrade keeper pointer", func() {
+			emptyUpgradeKeeperPointer := &upgradekeeper.Keeper{}
 
-			upgradeKeeper = emptyUpgradeKeeper
+			upgradeKeeper = emptyUpgradeKeeperPointer
 		}, false},
 		{"failure: empty scoped keeper", func() {
 			emptyScopedKeeper := capabilitykeeper.ScopedKeeper{}