reduce the range of the lock

group.go

@@ -597,8 +597,8 @@ func (g *OptGroup) Set(name string, value interface{}) {
 
 	// Check whether the current group or the option is frozen.
 	if g.optIsFrozen(name) {
-		g.conf.handleError(NewOptError(g.Name(), name, ErrFrozenOpt, value))
 		g.lock.Unlock()
+		g.conf.handleError(NewOptError(g.Name(), name, ErrFrozenOpt, value))
 		return
 	}
 
@@ -614,13 +614,12 @@ func (g *OptGroup) Set(name string, value interface{}) {
 			g.conf.UpdateValue(migrate, new)
 		}
 		g.conf.noticeOptChange(g.name, name, old, new, observers)
-		return
 	case ErrNoOpt:
-		g.conf.handleError(NewOptError(g.Name(), name, err, value))
 		g.lock.Unlock()
+		g.conf.handleError(NewOptError(g.Name(), name, err, value))
 	default:
-		g.conf.handleError(err)
 		g.lock.Unlock()
+		g.conf.handleError(err)
 	}
 }
 

opt.go

@@ -64,6 +64,8 @@ type Opt struct {
 	// When updating the option value, the validators will validate it.
 	// If there is a validator returns an error, the updating fails and
 	// returns the error. That's, these validators are the AND relations.
+	//
+	// Notice: they must not panic.
 	Validators []Validator
 }