took into account comments

tests/integration/distribution.go

@@ -1077,8 +1077,8 @@ func (s *CCVTestSuite) TestAllocateTokensToConsumerValidatorsWithDifferentValida
 
 	ctx, _ := s.providerCtx().CacheContext()
 	// If the provider chain has not yet reached `GetNumberOfEpochsToStartReceivingRewards * GetBlocksPerEpoch` block height,
-	// then all validators receive rewards. In this test, we want to check whether validators receive rewards or not based on how
-	// long they have been consumer validators. Because of this, we increase the block height.
+	// then all validators receive rewards (see `IsEligibleForConsumerRewards`). In this test, we want to check whether
+	// validators receive rewards or not based on how long they have been consumer validators. Because of this, we increase the block height.
 	ctx = ctx.WithBlockHeight(providerKeeper.GetNumberOfEpochsToStartReceivingRewards(ctx)*providerKeeper.GetBlocksPerEpoch(ctx) + 1)
 
 	// update the consumer validators

x/ccv/provider/keeper/distribution.go

@@ -127,6 +127,23 @@ func (k Keeper) AllocateTokens(ctx sdk.Context) {
 	}
 }
 
+// IsEligibleForConsumerRewards returns `true` if the validator with `consumerValidatorHeight` has been a consumer
+// validator for a long period of time and hence is eligible to receive rewards, and false otherwise
+func (k Keeper) IsEligibleForConsumerRewards(ctx sdk.Context, consumerValidatorHeight int64) bool {
+	numberOfBlocksToStartReceivingRewards := k.GetNumberOfEpochsToStartReceivingRewards(ctx) * k.GetBlocksPerEpoch(ctx)
+
+	// Note that at the beginning of the chain's life (e.g., when the block height of the chain is still small), no validator
+	// could have been a consumer validator for more than `NumberOfEpochsToStartReceivingRewards` epochs and hence in this
+	// case all validators are eligible for rewards, even though they might have not been a consumer validator on the
+	// consumer chain for more than a single epoch.
+	isChainStillNew := ctx.BlockHeight() < numberOfBlocksToStartReceivingRewards
+
+	// a validator is eligible for rewards if it has been a consumer validator for `NumberOfEpochsToStartReceivingRewards` epochs
+	hasBeenConsumerValidatorForLongEnough := (ctx.BlockHeight() - consumerValidatorHeight) >= numberOfBlocksToStartReceivingRewards
+
+	return isChainStillNew || hasBeenConsumerValidatorForLongEnough
+}
+
 // AllocateTokensToConsumerValidators allocates tokens
 // to the given consumer chain's validator set
 func (k Keeper) AllocateTokensToConsumerValidators(
@@ -147,10 +164,7 @@ func (k Keeper) AllocateTokensToConsumerValidators(
 
 	// Allocate tokens by iterating over the consumer validators
 	for _, consumerVal := range k.GetConsumerValSet(ctx, chainID) {
-
-		// do not distribute rewards to a validator that has not been validating long enough
-		numberOfBlocksToStartReceivingRewards := k.GetNumberOfEpochsToStartReceivingRewards(ctx) * k.GetBlocksPerEpoch(ctx)
-		if ctx.BlockHeight() >= numberOfBlocksToStartReceivingRewards && ctx.BlockHeight()-consumerVal.Height < numberOfBlocksToStartReceivingRewards {
+		if !k.IsEligibleForConsumerRewards(ctx, consumerVal.Height) {
 			continue
 		}
 
@@ -249,8 +263,7 @@ func (k Keeper) ComputeConsumerTotalVotingPower(ctx sdk.Context, chainID string)
 	for _, v := range k.GetConsumerValSet(ctx, chainID) {
 
 		// only consider the voting power of a validator that would receive rewards (i.e., validator has been validating for a number of blocks)
-		numberOfBlocksToStartReceivingRewards := k.GetNumberOfEpochsToStartReceivingRewards(ctx) * k.GetBlocksPerEpoch(ctx)
-		if ctx.BlockHeight() >= numberOfBlocksToStartReceivingRewards && ctx.BlockHeight()-v.Height < numberOfBlocksToStartReceivingRewards {
+		if !k.IsEligibleForConsumerRewards(ctx, v.Height) {
 			continue
 		}
 

x/ccv/provider/keeper/distribution_test.go

@@ -275,3 +275,24 @@ func TestGetConsumerRewardsAllocationNil(t *testing.T) {
 	}
 	require.Equal(t, expectedRewardAllocation, alloc)
 }
+
+func TestIsEligibleForConsumerRewards(t *testing.T) {
+	keeper, ctx, ctrl, _ := testkeeper.GetProviderKeeperAndCtx(t, testkeeper.NewInMemKeeperParams(t))
+	defer ctrl.Finish()
+
+	params := providertypes.DefaultParams()
+	params.NumberOfEpochsToStartReceivingRewards = 10
+	params.BlocksPerEpoch = 5
+	keeper.SetParams(ctx, params)
+
+	numberOfBlocks := params.NumberOfEpochsToStartReceivingRewards * params.BlocksPerEpoch
+
+	// if the provider's chain block height is less than `numberOfBlocks`, then irrespectively of the height of a consumer
+	// validator, the validator is eligible for rewards
+	require.True(t, keeper.IsEligibleForConsumerRewards(ctx.WithBlockHeight(numberOfBlocks-1), numberOfBlocks-1))
+
+	require.True(t, keeper.IsEligibleForConsumerRewards(ctx.WithBlockHeight(numberOfBlocks), 0))
+	require.True(t, keeper.IsEligibleForConsumerRewards(ctx.WithBlockHeight(numberOfBlocks+1), 0))
+	require.True(t, keeper.IsEligibleForConsumerRewards(ctx.WithBlockHeight(numberOfBlocks+1), 1))
+	require.False(t, keeper.IsEligibleForConsumerRewards(ctx.WithBlockHeight(numberOfBlocks+1), 2))
+}

x/ccv/provider/keeper/relay_test.go

@@ -88,7 +88,7 @@ func TestQueueVSCPackets(t *testing.T) {
 }
 
 // TestQueueVSCPacketsDoesNotResetConsumerValidatorsHeights checks that the heights of consumer validators are not
-// getting correctly updated
+// getting incorrectly updated
 func TestQueueVSCPacketsDoesNotResetConsumerValidatorsHeights(t *testing.T) {
 	providerKeeper, ctx, ctrl, mocks := testkeeper.GetProviderKeeperAndCtx(t, testkeeper.NewInMemKeeperParams(t))
 	defer ctrl.Finish()

x/ccv/provider/migrations/v6/migrations.go

@@ -9,10 +9,8 @@ import (
 
 // MigrateParams adds missing provider chain params to the param store.
 func MigrateParams(ctx sdk.Context, paramsSubspace paramtypes.Subspace) {
-	if paramsSubspace.HasKeyTable() {
-		paramsSubspace.Set(ctx, providertypes.KeyNumberOfEpochsToStartReceivingRewards, providertypes.DefaultNumberOfEpochsToStartReceivingRewards)
-	} else {
+	if !paramsSubspace.HasKeyTable() {
 		paramsSubspace.WithKeyTable(providertypes.ParamKeyTable())
-		paramsSubspace.Set(ctx, providertypes.KeyNumberOfEpochsToStartReceivingRewards, providertypes.DefaultNumberOfEpochsToStartReceivingRewards)
 	}
+	paramsSubspace.Set(ctx, providertypes.KeyNumberOfEpochsToStartReceivingRewards, providertypes.DefaultNumberOfEpochsToStartReceivingRewards)
 }