From 9cb48457c6a9db533d6759a31a49ba13f1bc591b Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Tue, 20 Apr 2021 10:44:12 +0200
Subject: [PATCH] ConnectionExists: respect requests for h1 connections better

... for situations when multiplexing isn't enabled on the h2 connection
and h1 is explicitly requested for the transfer.

Assisted-by: Gergely Nagy
---
 lib/url.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/url.c b/lib/url.c
index 949e380aa5..c5e59ea99b 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -1315,6 +1315,13 @@ ConnectionExists(struct Curl_easy *data,
         }
       }
 
+      /* If multiplexing isn't enabled on the h2 connection and h1 is
+         explicitly requested, handle it: */
+      if((needle->handler->protocol & PROTO_FAMILY_HTTP) &&
+         (check->httpversion >= 20) &&
+         (data->state.httpwant < CURL_HTTP_VERSION_2_0))
+        continue;
+
       if((needle->handler->flags&PROTOPT_SSL)
 #ifndef CURL_DISABLE_PROXY
          || !needle->bits.httpproxy || needle->bits.tunnel_proxy