From 7a86a25f5b73b86455cd977572250de0a6124524 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 4 May 2020 12:35:18 +0200
Subject: [PATCH] connect: make happy eyeballs work for QUIC (again)

Follow-up from dbd16c3e256c6c (regression in 7.70.0)

Closes #5334
---
 lib/connect.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/connect.c b/lib/connect.c
index b67d17722f..1d26d7bc02 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -873,8 +873,16 @@ CURLcode Curl_is_connected(struct connectdata *conn,
         conn->tempsock[i] = CURL_SOCKET_BAD;
         post_SOCKS(conn, sockindex, connected);
         connkeep(conn, "HTTP/3 default");
+        return result;
       }
-      return result;
+      /* should we try another protocol family? */
+      if(i == 0 && !conn->parallel_connect &&
+         (Curl_timediff(now, conn->connecttime) >=
+          data->set.happy_eyeballs_timeout)) {
+        conn->parallel_connect = TRUE; /* starting now */
+        trynextip(conn, sockindex, 1);
+      }
+      continue;
     }
 #endif