Prevent redundant autoloader registerations. Fixes #304

src/Mustache/Autoloader.php

@@ -16,6 +16,14 @@ class Mustache_Autoloader
 {
     private $baseDir;
 
+    /**
+     * An array where the key is the baseDir and the key is an instance of this
+     * class.
+     *
+     * @var array
+     */
+    static private $instances;
+
     /**
      * Autoloader constructor.
      *
@@ -45,7 +53,13 @@ class Mustache_Autoloader
      */
     public static function register($baseDir = null)
     {
-        $loader = new self($baseDir);
+        $key = $baseDir ? $baseDir : 0;
+
+        if (!isset(self::$instances[$key])) {
+            self::$instances[$key] = new self($baseDir);
+        }
+
+        $loader = self::$instances[$key];
         spl_autoload_register(array($loader, 'autoload'));
 
         return $loader;

test/Mustache/Test/AutoloaderTest.php

@@ -33,4 +33,21 @@ class Mustache_Test_AutoloaderTest extends PHPUnit_Framework_TestCase
         $loader->autoload('\Mustache_Bar');
         $this->assertTrue(class_exists('Mustache_Bar'));
     }
+    
+    /**
+     * Test that the autoloader won't register multiple times.
+     * 
+     * @return void
+     */
+    public function testRegisterMultiple()
+    {
+        $numLoaders = count(spl_autoload_functions());
+        
+        Mustache_Autoloader::register();
+        Mustache_Autoloader::register();
+        
+        $expectedNumLoaders = $numLoaders + 1;
+        
+        $this->assertCount($expectedNumLoaders, spl_autoload_functions());
+    }
 }