fixed topN == 0 issue

x/ccv/provider/keeper/partial_set_security.go

@@ -4,8 +4,8 @@ import (
 	errorsmod "cosmossdk.io/errors"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
-
 	"github.com/cosmos/interchain-security/v4/x/ccv/provider/types"
+	"math"
 	"sort"
 )
 
@@ -51,7 +51,7 @@ func (k Keeper) HandleOptOut(ctx sdk.Context, chainID string, providerAddr types
 			"opting out of an unknown or not running consumer chain, with id: %s", chainID)
 	}
 
-	if topN, found := k.GetTopN(ctx, chainID); found {
+	if topN, found := k.GetTopN(ctx, chainID); found && topN > 0 {
 		// a validator cannot opt out from a Top N chain if the validator is in the Top N validators
 		validator, validatorFound := k.stakingKeeper.GetValidatorByConsAddr(ctx, providerAddr.ToSdkConsAddr())
 		if !validatorFound {
@@ -60,7 +60,7 @@ func (k Keeper) HandleOptOut(ctx sdk.Context, chainID string, providerAddr types
 				"validator with consensus address %s could not be found", providerAddr.ToSdkConsAddr())
 		}
 		power := k.stakingKeeper.GetLastValidatorPower(ctx, validator.GetOperator())
-		minPowerToOptIn := k.ComputeMinPowerToOptIn(ctx, k.stakingKeeper.GetLastValidators(ctx), topN)
+		minPowerToOptIn := k.ComputeMinPowerToOptIn(ctx, chainID, k.stakingKeeper.GetLastValidators(ctx), topN)
 
 		if power >= minPowerToOptIn {
 			return errorsmod.Wrapf(
@@ -94,8 +94,16 @@ func (k Keeper) OptInTopNValidators(ctx sdk.Context, chainID string, bondedValid
 }
 
 // ComputeMinPowerToOptIn returns the minimum power needed for a validator (from the bonded validators)
-// to belong to the `topN` validators
-func (k Keeper) ComputeMinPowerToOptIn(ctx sdk.Context, bondedValidators []stakingtypes.Validator, topN uint32) int64 {
+// to belong to the `topN` validators. `chainID` is only used for logging purposes.
+func (k Keeper) ComputeMinPowerToOptIn(ctx sdk.Context, chainID string, bondedValidators []stakingtypes.Validator, topN uint32) int64 {
+	if topN == 0 {
+		// This should never happen but because `ComputeMinPowerToOptIn` is called during an `EndBlock` we do want
+		// to `panic` here. Instead, we log an error and return the maximum possible `int64`.
+		k.Logger(ctx).Error("trying to compute minimum power to opt in for a non-Top-N chain",
+			"chainID", chainID)
+		return math.MaxInt64
+	}
+
 	totalPower := sdk.ZeroDec()
 	var powers []int64
 

x/ccv/provider/keeper/partial_set_security_test.go

@@ -2,6 +2,7 @@ package keeper_test
 
 import (
 	"bytes"
+	"math"
 	"sort"
 	"testing"
 
@@ -271,16 +272,19 @@ func TestComputeMinPowerToOptIn(t *testing.T) {
 		createStakingValidator(ctx, mocks, 5, 6),
 	}
 
-	require.Equal(t, int64(1), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 100))
-	require.Equal(t, int64(1), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 97))
-	require.Equal(t, int64(3), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 96))
-	require.Equal(t, int64(3), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 85))
-	require.Equal(t, int64(5), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 84))
-	require.Equal(t, int64(5), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 65))
-	require.Equal(t, int64(6), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 64))
-	require.Equal(t, int64(6), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 41))
-	require.Equal(t, int64(10), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 40))
-	require.Equal(t, int64(10), providerKeeper.ComputeMinPowerToOptIn(ctx, bondedValidators, 1))
+	require.Equal(t, int64(1), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 100))
+	require.Equal(t, int64(1), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 97))
+	require.Equal(t, int64(3), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 96))
+	require.Equal(t, int64(3), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 85))
+	require.Equal(t, int64(5), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 84))
+	require.Equal(t, int64(5), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 65))
+	require.Equal(t, int64(6), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 64))
+	require.Equal(t, int64(6), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 41))
+	require.Equal(t, int64(10), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 40))
+	require.Equal(t, int64(10), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 1))
+
+	// exceptional case when we erroneously call with `topN == 0`
+	require.Equal(t, int64(math.MaxInt64), providerKeeper.ComputeMinPowerToOptIn(ctx, "chainID", bondedValidators, 0))
 }
 
 // TestShouldConsiderOnlyOptIn returns true if `validator` is opted in, in `chainID.

x/ccv/provider/keeper/proposal.go

@@ -291,7 +291,7 @@ func (k Keeper) MakeConsumerGenesis(
 
 	if prop.Top_N > 0 {
 		// in a Top-N chain, we automatically opt in all validators that belong to the top N
-		minPower := k.ComputeMinPowerToOptIn(ctx, bondedValidators, prop.Top_N)
+		minPower := k.ComputeMinPowerToOptIn(ctx, chainID, bondedValidators, prop.Top_N)
 		k.OptInTopNValidators(ctx, chainID, bondedValidators, minPower)
 	}
 

x/ccv/provider/keeper/relay.go

@@ -223,9 +223,9 @@ func (k Keeper) QueueVSCPackets(ctx sdk.Context) {
 	for _, chain := range k.GetAllConsumerChains(ctx) {
 		currentValidators := k.GetConsumerValSet(ctx, chain.ChainId)
 
-		if topN, found := k.GetTopN(ctx, chain.ChainId); found {
+		if topN, found := k.GetTopN(ctx, chain.ChainId); found && topN > 0 {
 			// in a Top-N chain, we automatically opt in all validators that belong to the top N
-			minPower := k.ComputeMinPowerToOptIn(ctx, bondedValidators, topN)
+			minPower := k.ComputeMinPowerToOptIn(ctx, chain.ChainId, bondedValidators, topN)
 			k.OptInTopNValidators(ctx, chain.ChainId, bondedValidators, minPower)
 		}