From 26c1c9ad052ae46eb77fda47fea6b2b7cfb6a605 Mon Sep 17 00:00:00 2001
From: Alec Thomas <alec@swapoff.org>
Date: Thu, 12 Sep 2024 12:05:09 +1000
Subject: [PATCH] fix: allow duplicate custom negated flags

Fixes #456
---
 build.go     |  3 +++
 kong_test.go | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/build.go b/build.go
index 7791c62..287beeb 100644
--- a/build.go
+++ b/build.go
@@ -173,6 +173,9 @@ MAIN:
 		if flag.Short != 0 {
 			delete(seenFlags, "-"+string(flag.Short))
 		}
+		if negFlag := negatableFlagName(flag.Name, flag.Tag.Negatable); negFlag != "" {
+			delete(seenFlags, negFlag)
+		}
 		for _, aflag := range flag.Aliases {
 			delete(seenFlags, "--"+aflag)
 		}
diff --git a/kong_test.go b/kong_test.go
index f05fc18..4785dd0 100644
--- a/kong_test.go
+++ b/kong_test.go
@@ -467,6 +467,19 @@ func TestDuplicateNegatableLong(t *testing.T) {
 	assert.EqualError(t, err, "<anonymous struct>.Two: duplicate negation flag --one")
 }
 
+func TestDuplicateNegatableFlagsInSubcommands(t *testing.T) {
+	cli2 := struct {
+		Sub struct {
+			Negated bool `negatable:"nope-"`
+		} `cmd:""`
+		Sub2 struct {
+			Negated bool `negatable:"nope-"`
+		} `cmd:""`
+	}{}
+	_, err := kong.New(&cli2)
+	assert.NoError(t, err)
+}
+
 func TestExistingNoFlag(t *testing.T) {
 	var cli struct {
 		Cmd struct {