use switch statement

errors/errors.go

@@ -35,8 +35,8 @@ type ValidationError string
 func NewValidationError(str string) error { return ValidationError(str) }
 func (e ValidationError) Error() string   { return string(e) }
 
-// StaleDataError is returned when a rule is modified but the
-// underlying data has changed and the rquest is no longer valid.
+// StaleDataError is returned when a rule modification is attempted but the
+// underlying data has changed and the change is no longer valid.
 type StaleDataError string
 
 // NewStaleDataError creates a new version mismatch error.

rules/store/kv/store.go

@@ -97,12 +97,12 @@ func (s *store) WriteRuleSet(rs rules.MutableRuleSet) error {
 	}
 	conditions, ops := []kv.Condition{rsCond}, []kv.Op{rsOp}
 	_, err = s.kvStore.Commit(conditions, ops)
-	if err != nil {
-		if err == kv.ErrConditionCheckFailed {
-			err = merrors.NewStaleDataError(err.Error())
-		}
+	switch err {
+	case kv.ErrConditionCheckFailed:
+		return merrors.NewStaleDataError(err.Error())
+	default:
+		return err
 	}
-	return err
 }
 
 func (s *store) WriteAll(nss *rules.Namespaces, rs rules.MutableRuleSet) error {