Small fixes on staking log and error (#2158)

* Small fixes on staking log and error

* Fix lint

core/state_transition.go

@@ -39,8 +39,8 @@ var (
 	errValidatorExist              = errors.New("staking validator already exists")
 	errValidatorNotExist           = errors.New("staking validator does not exist")
 	errNoDelegationToUndelegate    = errors.New("no delegation to undelegate")
-	errCommissionRateChangeTooFast = errors.New("commission rate can not be changed more than MaxChangeRate within the same epoch")
+	errCommissionRateChangeTooFast = errors.New("change on commission rate can not be more than max change rate within the same epoch")
-	errCommissionRateChangeTooHigh = errors.New("commission rate can not be higher than MaxCommissionRate")
+	errCommissionRateChangeTooHigh = errors.New("commission rate can not be higher than maximum commission rate")
 	errNoRewardsToCollect          = errors.New("no rewards to collect")
 	errNegativeAmount              = errors.New("amount can not be negative")
 )
@@ -491,11 +491,16 @@ func (st *StateTransition) applyDelegateTx(delegate *staking.Delegate) error {
 				delegation.Amount.Add(delegation.Amount, delegate.Amount)
 				err := stateDB.UpdateStakingInfo(wrapper.Validator.Address, wrapper)
 
+				if err != nil {
+					return err
+				}
 				// Secondly, if all locked token are used, try use the balance.
-				if err == nil && delegateBalance.Cmp(big.NewInt(0)) > 0 {
+				if delegateBalance.Cmp(big.NewInt(0)) > 0 {
 					stateDB.SubBalance(delegate.DelegatorAddress, delegateBalance)
+					return nil
 				}
-				return err
+				// This shouldn't really happen
+				return errInsufficientBalanceForStake
 			}
 			return errors.Wrapf(
 				errInsufficientBalanceForStake,

staking/types/validator.go

@@ -34,7 +34,7 @@ var (
 	errMinSelfDelegationTooSmall = errors.New("min_self_delegation has to be greater than 1 ONE")
 	errInvalidMaxTotalDelegation = errors.New("max_total_delegation can not be less than min_self_delegation")
 	errCommissionRateTooLarge    = errors.New("commission rate and change rate can not be larger than max commission rate")
-	errInvalidComissionRate      = errors.New("commission rate, change rate and max rate should be within 0-100 percent")
+	errInvalidCommissionRate     = errors.New("commission rate, change rate and max rate should be within 0-100 percent")
 	errNeedAtLeastOneSlotKey     = errors.New("need at least one slot key")
 	errBLSKeysNotMatchSigs       = errors.New("bls keys and corresponding signatures could not be verified")
 	errNilMinSelfDelegation      = errors.New("MinSelfDelegation can not be nil")
@@ -234,19 +234,19 @@ func (w *ValidatorWrapper) SanityCheck() error {
 
 	if w.Validator.Rate.LT(zeroPercent) || w.Validator.Rate.GT(hundredPercent) {
 		return errors.Wrapf(
-			errInvalidComissionRate, "rate:%s", w.Validator.Rate.String(),
+			errInvalidCommissionRate, "rate:%s", w.Validator.Rate.String(),
 		)
 	}
 
 	if w.Validator.MaxRate.LT(zeroPercent) || w.Validator.MaxRate.GT(hundredPercent) {
 		return errors.Wrapf(
-			errInvalidComissionRate, "rate:%s", w.Validator.MaxRate.String(),
+			errInvalidCommissionRate, "rate:%s", w.Validator.MaxRate.String(),
 		)
 	}
 
 	if w.Validator.MaxChangeRate.LT(zeroPercent) || w.Validator.MaxChangeRate.GT(hundredPercent) {
 		return errors.Wrapf(
-			errInvalidComissionRate, "rate:%s", w.Validator.MaxChangeRate.String(),
+			errInvalidCommissionRate, "rate:%s", w.Validator.MaxChangeRate.String(),
 		)
 	}