Merge PR #3836: Fix WithdrawValidatorCommission

PENDING.md

@@ -44,11 +44,13 @@
 * #3808 `gaiad` and `gaiacli` integration tests use ./build/ binaries.
 
 ### SDK
+
 * #3801 `baseapp` saftey improvements
 
 ### Tendermint
 
 ### CI/CD
+
 * [\198](https://github.com/cosmos/cosmos-sdk/pull/3832)
 
 <!--------------------------------- BUG FIXES -------------------------------->
@@ -63,4 +65,7 @@
 
 ### SDK
 
+* [\#3837] Fix `WithdrawValidatorCommission` to properly set the validator's
+remaining commission.
+
 ### Tendermint

types/dec_coin.go

@@ -179,7 +179,9 @@ func (coins DecCoins) TruncateDecimal() (Coins, DecCoins) {
 	for i, coin := range coins {
 		truncated, change := coin.TruncateDecimal()
 		out[i] = truncated
-		changeSum = changeSum.Add(DecCoins{change})
+		if !change.IsZero() {
+			changeSum = changeSum.Add(DecCoins{change})
+		}
 	}
 
 	return out, changeSum

x/distribution/keeper/keeper.go

@@ -79,9 +79,7 @@ func (k Keeper) WithdrawValidatorCommission(ctx sdk.Context, valAddr sdk.ValAddr
 	}
 
 	coins, remainder := commission.TruncateDecimal()
-
-	// leave remainder to withdraw later
-	k.SetValidatorAccumulatedCommission(ctx, valAddr, remainder)
+	k.SetValidatorAccumulatedCommission(ctx, valAddr, remainder) // leave remainder to withdraw later
 
 	// update outstanding
 	outstanding := k.GetValidatorOutstandingRewards(ctx, valAddr)

x/distribution/keeper/store.go

@@ -237,9 +237,16 @@ func (k Keeper) GetValidatorAccumulatedCommission(ctx sdk.Context, val sdk.ValAd
 
 // set accumulated commission for a validator
 func (k Keeper) SetValidatorAccumulatedCommission(ctx sdk.Context, val sdk.ValAddress, commission types.ValidatorAccumulatedCommission) {
+	var bz []byte
+
 	store := ctx.KVStore(k.storeKey)
-	b := k.cdc.MustMarshalBinaryLengthPrefixed(commission)
-	store.Set(GetValidatorAccumulatedCommissionKey(val), b)
+	if commission.IsZero() {
+		bz = k.cdc.MustMarshalBinaryLengthPrefixed(types.InitialValidatorAccumulatedCommission())
+	} else {
+		bz = k.cdc.MustMarshalBinaryLengthPrefixed(commission)
+	}
+
+	store.Set(GetValidatorAccumulatedCommissionKey(val), bz)
 }
 
 // delete accumulated commission for a validator