Merge branch '3.x' into 4.x

* 3.x:
  Make compatible with PHP<8
  Extract ReflectionCallable to make it reusable
  Make a small optimization
  [Doc] Fix `do` tag label in link

src/Util/ReflectionCallable.php

@@ -0,0 +1,84 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Util;
+
+/**
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
+ */
+final class ReflectionCallable
+{
+    private $reflector;
+    private $callable = null;
+    private $name;
+
+    public function __construct($callable, string $debugType = 'unknown', string $debugName = 'unknown')
+    {
+        if (\is_string($callable) && false !== $pos = strpos($callable, '::')) {
+            $callable = [substr($callable, 0, $pos), substr($callable, 2 + $pos)];
+        }
+
+        if (\is_array($callable) && method_exists($callable[0], $callable[1])) {
+            $this->reflector = $r = new \ReflectionMethod($callable[0], $callable[1]);
+            $this->callable = $callable;
+            $this->name = $r->class.'::'.$r->name;
+
+            return;
+        }
+
+        $checkVisibility = $callable instanceof \Closure;
+        try {
+            $closure = \Closure::fromCallable($callable);
+        } catch (\TypeError $e) {
+            throw new \LogicException(\sprintf('Callback for %s "%s" is not callable in the current scope.', $debugType, $debugName), 0, $e);
+        }
+        $this->reflector = $r = new \ReflectionFunction($closure);
+
+        if (str_contains($r->name, '{closure')) {
+            $this->callable = $callable;
+            $this->name = 'Closure';
+
+            return;
+        }
+
+        if ($object = $r->getClosureThis()) {
+            $callable = [$object, $r->name];
+            $this->name = get_debug_type($object).'::'.$r->name;
+        } elseif ($class = $r->getClosureCalledClass()) {
+            $this->name = $class->name.'::'.$r->name;
+        } else {
+            $callable = $this->name = $r->name;
+        }
+
+        if ($checkVisibility && \is_array($callable) && method_exists(...$callable) && !(new \ReflectionMethod(...$callable))->isPublic()) {
+            $callable = $r->getClosure();
+        }
+
+        $this->callable = $callable;
+    }
+
+    public function getReflector(): \ReflectionFunctionAbstract
+    {
+        return $this->reflector;
+    }
+
+    public function getCallable()
+    {
+        return $this->callable;
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+}