From e135867f9649c8be875fa562e54db9c27a045c8e Mon Sep 17 00:00:00 2001
From: Albert Nigmatzianov <albertnigma@gmail.com>
Date: Wed, 19 Apr 2017 11:17:48 +0200
Subject: [PATCH] Make parentsPflags more flexible

updateParentsPflags returns nothing, so you can use it independent of
mergePersistentFlags. A little performance impact.
---
 command.go | 43 +++++++++++--------------------------------
 1 file changed, 11 insertions(+), 32 deletions(-)

diff --git a/command.go b/command.go
index b4a6e668..329bbeae 100644
--- a/command.go
+++ b/command.go
@@ -1089,16 +1089,14 @@ func (c *Command) LocalFlags() *flag.FlagSet {
 		c.lflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
 		c.lflags.SetOutput(c.OutOrStderr())
 	}
-
-	flags := c.Flags()
-	c.lflags.SortFlags = flags.SortFlags
+	c.lflags.SortFlags = c.Flags().SortFlags
 
 	addToLocal := func(f *flag.Flag) {
 		if c.lflags.Lookup(f.Name) == nil && c.parentsPflags.Lookup(f.Name) == nil {
 			c.lflags.AddFlag(f)
 		}
 	}
-	c.flags.VisitAll(addToLocal)
+	c.Flags().VisitAll(addToLocal)
 	c.PersistentFlags().VisitAll(addToLocal)
 	return c.lflags
 }
@@ -1112,13 +1110,11 @@ func (c *Command) InheritedFlags() *flag.FlagSet {
 	}
 
 	local := c.LocalFlags()
-
 	c.parentsPflags.VisitAll(func(f *flag.Flag) {
 		if c.iflags.Lookup(f.Name) == nil && local.Lookup(f.Name) == nil {
 			c.iflags.AddFlag(f)
 		}
 	})
-
 	return c.iflags
 }
 
@@ -1204,8 +1200,9 @@ func (c *Command) persistentFlag(name string) (flag *flag.Flag) {
 		flag = c.PersistentFlags().Lookup(name)
 	}
 
-	if flag == nil && c.HasParent() {
-		flag = c.parent.persistentFlag(name)
+	if flag == nil {
+		c.updateParentsPflags()
+		flag = c.parentsPflags.Lookup(name)
 	}
 	return
 }
@@ -1229,23 +1226,14 @@ func (c *Command) Parent() *Command {
 // and adds missing persistent flags of all parents.
 func (c *Command) mergePersistentFlags() {
 	c.Flags().AddFlagSet(c.PersistentFlags())
-
-	added := c.updateParentsPflags()
-	if len(added) > 0 {
-		for _, f := range added {
-			if c.Flags().Lookup(f.Name) == nil {
-				c.Flags().AddFlag(f)
-			}
-		}
-	}
+	c.updateParentsPflags()
+	c.Flags().AddFlagSet(c.parentsPflags)
 }
 
 // updateParentsPflags updates c.parentsPflags by adding
-// new persistent flags of all parents and returns added flags.
+// new persistent flags of all parents.
 // If c.parentsPflags == nil, it makes new.
-//
-// This function must be used ONLY in mergePersistentFlags.
-func (c *Command) updateParentsPflags() (added []*flag.Flag) {
+func (c *Command) updateParentsPflags() {
 	if c.parentsPflags == nil {
 		c.parentsPflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
 		c.parentsPflags.SetOutput(c.OutOrStderr())
@@ -1254,16 +1242,7 @@ func (c *Command) updateParentsPflags() (added []*flag.Flag) {
 
 	c.Root().PersistentFlags().AddFlagSet(flag.CommandLine)
 
-	c.VisitParents(func(x *Command) {
-		if x.HasPersistentFlags() {
-			x.PersistentFlags().VisitAll(func(f *flag.Flag) {
-				if c.parentsPflags.Lookup(f.Name) == nil {
-					c.parentsPflags.AddFlag(f)
-					added = append(added, f)
-				}
-			})
-		}
+	c.VisitParents(func(parent *Command) {
+		c.parentsPflags.AddFlagSet(parent.PersistentFlags())
 	})
-
-	return added
 }