From 22b617914c8890ba20db7ceafcdc2ef4ca4817d3 Mon Sep 17 00:00:00 2001
From: Brian Pursley <bpursley@cinlogic.com>
Date: Sun, 28 Aug 2022 12:46:39 -0400
Subject: [PATCH] fix: show flags that shadow parent persistent flag in child
 help (#1776)

This fixes a bug where a child flag that shadows (has the same
name as) a parent persistent flag would not be shown in the
child command's help output and the parent flag would be shown
instead under the global flags section.

This change makes the help output consistent with the
observed behavior during execution, where the child flag is
the one that is actually used.
---
 command.go      |  3 ++-
 command_test.go | 39 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/command.go b/command.go
index 675bb1340..5fca7dc63 100644
--- a/command.go
+++ b/command.go
@@ -1505,7 +1505,8 @@ func (c *Command) LocalFlags() *flag.FlagSet {
 	}
 
 	addToLocal := func(f *flag.Flag) {
-		if c.lflags.Lookup(f.Name) == nil && c.parentsPflags.Lookup(f.Name) == nil {
+		// Add the flag if it is not a parent PFlag, or it shadows a parent PFlag
+		if c.lflags.Lookup(f.Name) == nil && f != c.parentsPflags.Lookup(f.Name) {
 			c.lflags.AddFlag(f)
 		}
 	}
diff --git a/command_test.go b/command_test.go
index 0446e3c1d..0b0b82132 100644
--- a/command_test.go
+++ b/command_test.go
@@ -707,10 +707,7 @@ func TestEmptyInputs(t *testing.T) {
 	}
 }
 
-func TestOverwrittenFlag(t *testing.T) {
-	// TODO: This test fails, but should work.
-	t.Skip()
-
+func TestChildFlagShadowsParentPersistentFlag(t *testing.T) {
 	parent := &Command{Use: "parent", Run: emptyRun}
 	child := &Command{Use: "child", Run: emptyRun}
 
@@ -732,7 +729,7 @@ func TestOverwrittenFlag(t *testing.T) {
 	}
 
 	if childInherited.Lookup("intf") != nil {
-		t.Errorf(`InheritedFlags should not contain overwritten flag "intf"`)
+		t.Errorf(`InheritedFlags should not contain shadowed flag "intf"`)
 	}
 	if childLocal.Lookup("intf") == nil {
 		t.Error(`LocalFlags expected to contain "intf", got "nil"`)
@@ -887,6 +884,38 @@ func TestHelpCommandExecutedOnChild(t *testing.T) {
 	checkStringContains(t, output, childCmd.Long)
 }
 
+func TestHelpCommandExecutedOnChildWithFlagThatShadowsParentFlag(t *testing.T) {
+	parent := &Command{Use: "parent", Run: emptyRun}
+	child := &Command{Use: "child", Run: emptyRun}
+	parent.AddCommand(child)
+
+	parent.PersistentFlags().Bool("foo", false, "parent foo usage")
+	parent.PersistentFlags().Bool("bar", false, "parent bar usage")
+	child.Flags().Bool("foo", false, "child foo usage") // This shadows parent's foo flag
+	child.Flags().Bool("baz", false, "child baz usage")
+
+	got, err := executeCommand(parent, "help", "child")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	expected := `Usage:
+  parent child [flags]
+
+Flags:
+      --baz    child baz usage
+      --foo    child foo usage
+  -h, --help   help for child
+
+Global Flags:
+      --bar   parent bar usage
+`
+
+	if got != expected {
+		t.Errorf("Help text mismatch.\nExpected:\n%s\n\nGot:\n%s\n", expected, got)
+	}
+}
+
 func TestSetHelpCommand(t *testing.T) {
 	c := &Command{Use: "c", Run: emptyRun}
 	c.AddCommand(&Command{Use: "empty", Run: emptyRun})