From 4078b73cec8eb8baad10a7593b1c917b9c7b26d8 Mon Sep 17 00:00:00 2001
From: Arjen Poutsma <poutsmaa@vmware.com>
Date: Mon, 10 Jan 2022 10:54:04 +0100
Subject: [PATCH] NettyHeadersAdapter::putAll does not overwrite headers

NettyHeadersAdapter::putAll uses HttpHeaders::add, which does not
overwrite existing headers. putAll should use HttpHeaders::set instead,
just like NettyHeadersAdapter::put does.

Closes gh-27887
---
 .../http/server/reactive/NettyHeadersAdapter.java               | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/NettyHeadersAdapter.java b/spring-web/src/main/java/org/springframework/http/server/reactive/NettyHeadersAdapter.java
index 08ae3207f9..92da6c4b14 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/NettyHeadersAdapter.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/NettyHeadersAdapter.java
@@ -147,7 +147,7 @@ class NettyHeadersAdapter implements MultiValueMap<String, String> {
 
 	@Override
 	public void putAll(Map<? extends String, ? extends List<String>> map) {
-		map.forEach(this.headers::add);
+		map.forEach(this.headers::set);
 	}
 
 	@Override