From 637ba7bbc1b7b22a9118597d39c3896851a93d7f Mon Sep 17 00:00:00 2001
From: Dmytro Milinevskyi <dmytro.milinevskyi@datadoghq.com>
Date: Sat, 6 Jan 2024 18:06:53 +0100
Subject: [PATCH] Revert "flags: clarify documentation that LocalFlags related
 function do not modify the state"

This reverts commit 52e7b45312f82ec91ad00508f9b0d1be856f3809.
---
 command.go | 48 +++++++++++++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/command.go b/command.go
index ba34628f..2fbe6c13 100644
--- a/command.go
+++ b/command.go
@@ -153,6 +153,10 @@ type Command struct {
 	flags *flag.FlagSet
 	// pflags contains persistent flags.
 	pflags *flag.FlagSet
+	// lflags contains local flags.
+	lflags *flag.FlagSet
+	// iflags contains inherited flags.
+	iflags *flag.FlagSet
 	// parentsPflags is all persistent flags of cmd's parents.
 	parentsPflags *flag.FlagSet
 	// globNormFunc is the global normalization function
@@ -1649,7 +1653,6 @@ func (c *Command) Flags() *flag.FlagSet {
 }
 
 // LocalNonPersistentFlags are flags specific to this command which will NOT persist to subcommands.
-// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) LocalNonPersistentFlags() *flag.FlagSet {
 	persistentFlags := c.PersistentFlags()
 
@@ -1663,57 +1666,58 @@ func (c *Command) LocalNonPersistentFlags() *flag.FlagSet {
 }
 
 // LocalFlags returns the local FlagSet specifically set in the current command.
-// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) LocalFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
-	lflags := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
-	if c.flagErrorBuf == nil {
-		c.flagErrorBuf = new(bytes.Buffer)
+	if c.lflags == nil {
+		c.lflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		if c.flagErrorBuf == nil {
+			c.flagErrorBuf = new(bytes.Buffer)
+		}
+		c.lflags.SetOutput(c.flagErrorBuf)
 	}
-	lflags.SetOutput(c.flagErrorBuf)
-	lflags.SortFlags = c.Flags().SortFlags
+	c.lflags.SortFlags = c.Flags().SortFlags
 	if c.globNormFunc != nil {
-		lflags.SetNormalizeFunc(c.globNormFunc)
+		c.lflags.SetNormalizeFunc(c.globNormFunc)
 	}
 
 	addToLocal := func(f *flag.Flag) {
 		// Add the flag if it is not a parent PFlag, or it shadows a parent PFlag
-		if lflags.Lookup(f.Name) == nil && f != c.parentsPflags.Lookup(f.Name) {
-			lflags.AddFlag(f)
+		if c.lflags.Lookup(f.Name) == nil && f != c.parentsPflags.Lookup(f.Name) {
+			c.lflags.AddFlag(f)
 		}
 	}
 	c.Flags().VisitAll(addToLocal)
 	c.PersistentFlags().VisitAll(addToLocal)
-	return lflags
+	return c.lflags
 }
 
 // InheritedFlags returns all flags which were inherited from parent commands.
-// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) InheritedFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
-	iflags := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
-	if c.flagErrorBuf == nil {
-		c.flagErrorBuf = new(bytes.Buffer)
+	if c.iflags == nil {
+		c.iflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		if c.flagErrorBuf == nil {
+			c.flagErrorBuf = new(bytes.Buffer)
+		}
+		c.iflags.SetOutput(c.flagErrorBuf)
 	}
-	iflags.SetOutput(c.flagErrorBuf)
 
 	local := c.LocalFlags()
 	if c.globNormFunc != nil {
-		iflags.SetNormalizeFunc(c.globNormFunc)
+		c.iflags.SetNormalizeFunc(c.globNormFunc)
 	}
 
 	c.parentsPflags.VisitAll(func(f *flag.Flag) {
-		if iflags.Lookup(f.Name) == nil && local.Lookup(f.Name) == nil {
-			iflags.AddFlag(f)
+		if c.iflags.Lookup(f.Name) == nil && local.Lookup(f.Name) == nil {
+			c.iflags.AddFlag(f)
 		}
 	})
-	return iflags
+	return c.iflags
 }
 
 // NonInheritedFlags returns all flags which were not inherited from parent commands.
-// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) NonInheritedFlags() *flag.FlagSet {
 	return c.LocalFlags()
 }
@@ -1739,6 +1743,8 @@ func (c *Command) ResetFlags() {
 	c.pflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
 	c.pflags.SetOutput(c.flagErrorBuf)
 
+	c.lflags = nil
+	c.iflags = nil
 	c.parentsPflags = nil
 }