Better type description on PHPDoc, better testing of returned value.

doc/advanced.rst

@@ -596,7 +596,7 @@ An extension is a class that implements the following interface::
         /**
          * Returns a list of operators to add to the existing list.
          *
-         * @return array An array of operators
+         * @return array<array> First array of unary operators, second array of binary operators
          */
         function getOperators();
 

doc/advanced_legacy.rst

@@ -580,7 +580,7 @@ An extension is a class that implements the following interface::
         /**
          * Returns a list of operators to add to the existing list.
          *
-         * @return array An array of operators
+         * @return array<array> First array of unary operators, second array of binary operators
          */
         function getOperators();
 

lib/Twig/Environment.php

@@ -1512,8 +1512,15 @@ class Twig_Environment
 
         // operators
         if ($operators = $extension->getOperators()) {
+            if (!is_array($operators)) {
+                throw new InvalidArgumentException(sprintf(
+                    '"%s::getOperators()" must return an array with operators, got "%s".',
+                    get_class($extension), is_object($operators) ? get_class($operators) : gettype($operators).(is_resource($operators) ? '' : '#'.$operators)
+                ));
+            }
+
             if (2 !== count($operators)) {
-                throw new InvalidArgumentException(sprintf('"%s::getOperators()" does not return a valid operators array.', get_class($extension)));
+                throw new InvalidArgumentException(sprintf('"%s::getOperators()" must return an array of 2 elements, got %d.', get_class($extension), count($operators)));
             }
 
             $this->unaryOperators = array_merge($this->unaryOperators, $operators[0]);

lib/Twig/ExtensionInterface.php

@@ -63,7 +63,7 @@ interface Twig_ExtensionInterface
     /**
      * Returns a list of operators to add to the existing list.
      *
-     * @return array An array of operators
+     * @return array<array> First array of unary operators, second array of binary operators
      */
     public function getOperators();
 

test/Twig/Tests/CustomExtensionTest.php

@@ -0,0 +1,86 @@
+<?php
+
+final class CustomExtensionTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @param Twig_ExtensionInterface $extension
+     * @param string                  $expectedExceptionMessage
+     *
+     * @requires PHP 5.3
+     * @dataProvider provideInvalidExtensions
+     */
+    public function testGetInvalidOperators(\Twig_ExtensionInterface $extension, $expectedExceptionMessage)
+    {
+        $this->setExpectedException('InvalidArgumentException', $expectedExceptionMessage);
+
+        $loader = new \Twig_Loader_Array(array('foo' => '{{ foo }}'));
+        $env = new \Twig_Environment($loader);
+        $env->addExtension($extension);
+
+        $method = new \ReflectionMethod($env, 'initExtensions');
+        $method->setAccessible(true);
+        $method->invoke($env);
+    }
+
+    public function provideInvalidExtensions()
+    {
+        return array(
+            array(new InvalidOperatorExtension(new \stdClass()), '"InvalidOperatorExtension::getOperators()" must return an array with operators, got "stdClass".'),
+            array(new InvalidOperatorExtension(array(1, 2, 3)), '"InvalidOperatorExtension::getOperators()" must return an array of 2 elements, got 3.'),
+        );
+    }
+}
+
+final class InvalidOperatorExtension implements \Twig_ExtensionInterface
+{
+    private $operators;
+
+    public function __construct($operators)
+    {
+        $this->operators = $operators;
+    }
+
+    public function initRuntime(Twig_Environment $environment)
+    {
+    }
+
+    public function getTokenParsers()
+    {
+        return array();
+    }
+
+    public function getNodeVisitors()
+    {
+        return array();
+    }
+
+    public function getFilters()
+    {
+        return array();
+    }
+
+    public function getTests()
+    {
+        return array();
+    }
+
+    public function getFunctions()
+    {
+        return array();
+    }
+
+    public function getGlobals()
+    {
+        return array();
+    }
+
+    public function getOperators()
+    {
+        return $this->operators;
+    }
+
+    public function getName()
+    {
+        return __CLASS__;
+    }
+}