use the empty string instead of null as an array offset

Author: xabbuh

ResponseHeaderBag.php

@@ -174,7 +174,7 @@ public function getCacheControlDirective(string $key): bool|string|null
  */
  public function setCookie(Cookie $cookie)
  {
- $this->cookies[$cookie->getDomain()][$cookie->getPath()][$cookie->getName()] = $cookie;
+ $this->cookies[$cookie->getDomain() ?? ''][$cookie->getPath()][$cookie->getName()] = $cookie;
  $this->headerNames['set-cookie'] = 'Set-Cookie';
  }
 
@@ -187,13 +187,13 @@ public function removeCookie(string $name, ?string $path = '/', ?string $domain
  {
  $path ??= '/';
 
- unset($this->cookies[$domain][$path][$name]);
+ unset($this->cookies[$domain ?? ''][$path][$name]);
 
- if (empty($this->cookies[$domain][$path])) {
- unset($this->cookies[$domain][$path]);
+ if (empty($this->cookies[$domain ?? ''][$path])) {
+ unset($this->cookies[$domain ?? ''][$path]);
 
- if (empty($this->cookies[$domain])) {
- unset($this->cookies[$domain]);
+ if (empty($this->cookies[$domain ?? ''])) {
+ unset($this->cookies[$domain ?? '']);
  }
  }