From 721996a14439c15e81e1d8fec96e2c1ce4f1533a Mon Sep 17 00:00:00 2001
From: Nicolas Grekas <nicolas.grekas@gmail.com>
Date: Mon, 28 Feb 2022 14:17:32 +0100
Subject: [PATCH] [HttpClient] fix checking for unset property on PHP <= 7.1.4

---
 src/Symfony/Component/HttpClient/HttpClientTrait.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Symfony/Component/HttpClient/HttpClientTrait.php b/src/Symfony/Component/HttpClient/HttpClientTrait.php
index de1689490e623..57d48aade8db2 100644
--- a/src/Symfony/Component/HttpClient/HttpClientTrait.php
+++ b/src/Symfony/Component/HttpClient/HttpClientTrait.php
@@ -189,7 +189,7 @@ private static function mergeDefaultOptions(array $options, array $defaultOption
 
         $options += $defaultOptions;
 
-        foreach (self::$emptyDefaults ?? [] as $k => $v) {
+        foreach (isset(self::$emptyDefaults) ? self::$emptyDefaults : [] as $k => $v) {
             if (!isset($options[$k])) {
                 $options[$k] = $v;
             }