From ea6ce0afade4d74d32512fd17c9940e3a1322bea Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Sun, 17 Jan 2021 18:20:06 +0100
Subject: [PATCH] http: make providing Proxy-Connection header not cause
 duplicated headers

Fixes test 1180

Bug: https://curl.se/mail/lib-2021-01/0095.html
Reported-by: Fabian Keil
Closes #6472
---
 lib/http.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/http.c b/lib/http.c
index 993dc61af..520ac1070 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -3123,6 +3123,7 @@ CURLcode Curl_http(struct Curl_easy *data, bool *done)
 #ifndef CURL_DISABLE_PROXY
                   (conn->bits.httpproxy &&
                    !conn->bits.tunnel_proxy &&
+                   !Curl_checkheaders(data, "Proxy-Connection") &&
                    !Curl_checkProxyheaders(data, conn, "Proxy-Connection"))?
                   "Proxy-Connection: Keep-Alive\r\n":"",
 #else