From 8c16891c6e7a4738d63788f4447614056ab5136e Mon Sep 17 00:00:00 2001
From: Taylor Otwell <taylorotwell@gmail.com>
Date: Tue, 27 Oct 2020 13:50:24 -0500
Subject: [PATCH] add isCallable helper

---
 src/Illuminate/Support/Reflector.php   | 42 ++++++++++++++++++++++++++
 tests/Support/SupportReflectorTest.php | 26 ++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/src/Illuminate/Support/Reflector.php b/src/Illuminate/Support/Reflector.php
index fb597f5141f1..5490b0923ff2 100644
--- a/src/Illuminate/Support/Reflector.php
+++ b/src/Illuminate/Support/Reflector.php
@@ -3,10 +3,52 @@
 namespace Illuminate\Support;
 
 use ReflectionClass;
+use ReflectionMethod;
 use ReflectionNamedType;
 
 class Reflector
 {
+    /**
+     * This is a PHP 7.4 compatible implementation of is_callable.
+     *
+     * @param  mixed  $var
+     * @param  bool  $syntaxOnly
+     * @return bool
+     */
+    public static function isCallable($var, $syntaxOnly = false)
+    {
+        if (! is_array($var)) {
+            return is_callable($var, $syntaxOnly);
+        }
+
+        if (! isset($var[0]) && ! isset($var[1]) ||
+            ! is_string($var[1])) {
+            return false;
+        }
+
+        $class = is_object($var[0]) ? get_class($var[0]) : $var[0];
+
+        $method = $var[1];
+
+        if (! class_exists($class)) {
+            return false;
+        }
+
+        if (method_exists($class, $method)) {
+            return (new ReflectionMethod($class, $method))->isPublic();
+        }
+
+        if (is_object($var[0]) && method_exists($class, '__call')) {
+            return (new ReflectionMethod($class, '__call'))->isPublic();
+        }
+
+        if (! is_object($var[0]) && method_exists($class, '__callStatic')) {
+            return (new ReflectionMethod($class, '__callStatic'))->isPublic();
+        }
+
+        return false;
+    }
+
     /**
      * Get the class name of the given parameter's type, if possible.
      *
diff --git a/tests/Support/SupportReflectorTest.php b/tests/Support/SupportReflectorTest.php
index 55c4940f7543..8f5f394ca520 100644
--- a/tests/Support/SupportReflectorTest.php
+++ b/tests/Support/SupportReflectorTest.php
@@ -57,6 +57,16 @@ public function testUnionTypeName()
 
         $this->assertNull(Reflector::getParameterClassName($method->getParameters()[0]));
     }
+
+    public function testIsCallable()
+    {
+        $this->assertTrue(Reflector::isCallable(function () {}));
+        $this->assertTrue(Reflector::isCallable([B::class, 'f']));
+        $this->assertFalse(Reflector::isCallable([TestClassWithCall::class, 'f']));
+        $this->assertTrue(Reflector::isCallable([new TestClassWithCall, 'f']));
+        $this->assertTrue(Reflector::isCallable([TestClassWithCallStatic::class, 'f']));
+        $this->assertFalse(Reflector::isCallable([new TestClassWithCallStatic, 'f']));
+    }
 }
 
 class A
@@ -82,3 +92,19 @@ public function f(A|Model $x)
 }'
     );
 }
+
+class TestClassWithCall
+{
+    public function __call($method, $parameters)
+    {
+
+    }
+}
+
+class TestClassWithCallStatic
+{
+    public static function __callStatic($method, $parameters)
+    {
+
+    }
+}