Fix compat with older versions of PHP

src/Environment.php

@@ -131,7 +131,7 @@ class Environment
         $this->setCache($options['cache']);
         $this->extensionSet = new ExtensionSet();
         $this->defaultRuntimeLoader = new FactoryRuntimeLoader([
-            EscaperRuntime::class => fn () => new EscaperRuntime($options['autoescape'], $this->charset),
+            EscaperRuntime::class => function () use ($options) { return new EscaperRuntime($options['autoescape'], $this->charset); },
         ]);
 
         $this->addExtension(new CoreExtension());

src/Extension/EscaperExtension.php

@@ -21,12 +21,13 @@ use Twig\TwigFilter;
 
 final class EscaperExtension extends AbstractExtension
 {
-    private ?Environment $environment = null;
-    private array $escapers = [];
+    private $environment;
+    private $escapers = [];
+    private $escaper;
 
-    public function __construct(
-        private EscaperRuntime $escaper,
-    ) {
+    public function __construct(EscaperRuntime $escaper)
+    {
+        $this->escaper = $escaper;
     }
 
     public function getTokenParsers(): array
@@ -94,7 +95,7 @@ final class EscaperExtension extends AbstractExtension
     {
         trigger_deprecation('twig/twig', '3.10', 'The "%s()" method is deprecated, use the "Twig\Runtime\EscaperRuntime::setEscaper()" method instead (be warned that Environment is not passed anymore to the callable).', __METHOD__);
 
-        if (!$this->environment) {
+        if (!isset($this->environment)) {
             throw new \LogicException('You must call setEnvironment() before calling setEscaper().');
         }
 

src/Runtime/EscaperRuntime.php

@@ -27,16 +27,17 @@ final class EscaperRuntime implements RuntimeExtensionInterface
     /** @internal */
     public $safeLookup = [];
 
+    private $charset;
+
     /**
      * @param string|false|callable $defaultStrategy An escaping strategy
      *
      * @see setDefaultStrategy()
      */
-    public function __construct(
-        $defaultStrategy = 'html',
-        private string $charset = 'UTF-8',
-    ) {
+    public function __construct($defaultStrategy = 'html', $charset = 'UTF-8')
+    {
         $this->setDefaultStrategy($defaultStrategy);
+        $this->charset = $charset;
     }
 
     /**
@@ -127,7 +128,7 @@ final class EscaperRuntime implements RuntimeExtensionInterface
      *
      * @throws RuntimeException
      */
-    public function escape($string, string $strategy = 'html', ?string $charset = null, bool $autoescape = false): mixed
+    public function escape($string, string $strategy = 'html', ?string $charset = null, bool $autoescape = false)
     {
         if ($autoescape && $string instanceof Markup) {
             return $string;