From 99610791968a1b10dd28aa7dbf426ea3bad72aed Mon Sep 17 00:00:00 2001
From: Erik Dubbelboer <erik@dubbelboer.com>
Date: Wed, 11 May 2022 16:10:43 +0200
Subject: [PATCH] Fix userdata re-use after Remove

See also: https://github.com/valyala/fasthttp/pull/1298
---
 userdata.go      |  2 +-
 userdata_test.go | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/userdata.go b/userdata.go
index 9a7c98835c..37f7d9b1f9 100644
--- a/userdata.go
+++ b/userdata.go
@@ -81,7 +81,7 @@ func (d *userData) Remove(key string) {
 		kv := &args[i]
 		if string(kv.key) == key {
 			n--
-			args[i] = args[n]
+			args[i], args[n] = args[n], args[i]
 			args[n].value = nil
 			args = args[:n]
 			*d = args
diff --git a/userdata_test.go b/userdata_test.go
index c46a3e9c46..3a081aeead 100644
--- a/userdata_test.go
+++ b/userdata_test.go
@@ -104,3 +104,18 @@ func TestUserDataDelete(t *testing.T) {
 	}
 
 }
+
+func TestUserDataSetAndRemove(t *testing.T) {
+	var (
+		u        userData
+		shortKey = "[]"
+		longKey  = "[  ]"
+	)
+
+	u.Set(shortKey, "")
+	u.Set(longKey, "")
+	u.Remove(shortKey)
+	u.Set(shortKey, "")
+	testUserDataGet(t, &u, []byte(shortKey), "")
+	testUserDataGet(t, &u, []byte(longKey), "")
+}