Merge pull request #3375 from cosmos/bez/3355-sim-failure-debug

Simulation Fee Deduction Fixes

x/auth/simulation/fake.go

@@ -34,18 +34,25 @@ func SimulateDeductFee(m auth.AccountKeeper, f auth.FeeCollectionKeeper) simulat
 			return action, nil, nil
 		}
 
-		coins := sdk.Coins{sdk.NewCoin(initCoins[denomIndex].Denom, amt)}
-		err = stored.SetCoins(initCoins.Minus(coins))
-		if err != nil {
-			panic(err)
+		fees := sdk.Coins{sdk.NewCoin(initCoins[denomIndex].Denom, amt)}
+		newCoins, hasNeg := initCoins.SafeMinus(fees)
+		if hasNeg {
+			event(fmt.Sprintf("auth/SimulateDeductFee/false"))
+			return action, nil, nil
 		}
-		m.SetAccount(ctx, stored)
-		if !coins.IsNotNegative() {
-			panic("setting negative fees")
+
+		if _, hasNeg := initCoins.SafeMinus(fees); hasNeg {
+			event(fmt.Sprintf("auth/SimulateDeductFee/false"))
+			return action, nil, nil
 		}
 
-		f.AddCollectedFees(ctx, coins)
+		err = stored.SetCoins(newCoins)
+		if err != nil {
+			panic(err)
+		}
 
+		m.SetAccount(ctx, stored)
+		f.AddCollectedFees(ctx, fees)
 		event(fmt.Sprintf("auth/SimulateDeductFee/true"))
 
 		action = "TestDeductFee"