Set optional parameter default value to null

Makes it less magical that it behaves differently when the parameter is omitted.

src/Illuminate/Support/Arr.php

@@ -448,13 +448,13 @@ public static function pull(&$array, $key, $default = null)
      *
      * @throws \InvalidArgumentException
      */
-    public static function random($array, $amount = 1)
+    public static function random($array, $amount = null)
     {
-        if ($amount > ($count = count($array))) {
-            throw new InvalidArgumentException("You requested {$amount} items, but there are only {$count} items in the array.");
+        if (($requested = $amount ?: 1) > ($count = count($array))) {
+            throw new InvalidArgumentException("You requested {$requested} items, but there are only {$count} items in the array.");
         }
 
-        if (count(func_get_args()) == 1) {
+        if (is_null($amount)) {
             return $array[array_rand($array)];
         }
 

src/Illuminate/Support/Collection.php

@@ -1077,13 +1077,13 @@ public function put($key, $value)
      *
      * @throws \InvalidArgumentException
      */
-    public function random($amount = 1)
+    public function random($amount = null)
     {
-        if ($amount > ($count = $this->count())) {
-            throw new InvalidArgumentException("You requested {$amount} items, but there are only {$count} items in the collection.");
+        if (($requested = $amount ?: 1) > ($count = $this->count())) {
+            throw new InvalidArgumentException("You requested {$requested} items, but there are only {$count} items in the collection.");
         }
 
-        if (count(func_get_args()) == 0) {
+        if (is_null($amount)) {
             return Arr::random($this->items);
         }
 

src/Illuminate/Support/helpers.php

@@ -253,12 +253,8 @@ function array_pull(&$array, $key, $default = null)
      * @param  int|null  $num
      * @return mixed
      */
-    function array_random($array, $num = 1)
+    function array_random($array, $num = null)
     {
-        if (count(func_get_args()) == 1) {
-            return Arr::random($array);
-        }
-
         return Arr::random($array, $num);
     }
 }