fix empty

Author: taylorotwell

src/Illuminate/Collections/Arr.php

@@ -718,6 +718,10 @@ public static function shuffle($array, $seed = null)
             return $array;
         }
 
+        if (empty($array)) {
+            return [];
+        }
+
         $keys = array_keys($array);
 
         for ($i = count($keys) - 1; $i > 0; $i--) {

tests/Support/SupportArrTest.php

@@ -860,6 +860,11 @@ public function testShuffle()
         $this->assertTrue($dontMatch, 'Shuffled array should not have the same order.');
     }
 
+    public function testEmptyShuffle()
+    {
+        $this->assertEquals([], Arr::shuffle([]));
+    }
+
     public function testSort()
     {
         $unsorted = [