refactor, more robust flag propagation

command.go

@@ -57,6 +57,14 @@ func (c Command) Run(ctx *Context) error {
 		return err
 	}
 
+	nerr := normalizeFlags(c.Flags, set)
+	if nerr != nil {
+		fmt.Println(nerr)
+		fmt.Println("")
+		ShowCommandHelp(ctx, c.Name)
+		fmt.Println("")
+		return nerr
+	}
 	context := NewContext(ctx.App, set, ctx.globalSet)
 	if checkCommandHelp(context, c.Name) {
 		return nil