Return null instead of empty array object or collection for non-array

Author: a-bashtannik

src/Illuminate/Database/Eloquent/Casts/AsArrayObject.php

@@ -21,7 +21,7 @@ public function get($model, $key, $value, $attributes)
             {
                 $data = json_decode($attributes[$key], true);
 
-                return is_array($data) ? new ArrayObject($data) : new ArrayObject();
+                return is_array($data) ? new ArrayObject($data) : null;
             }
 
             public function set($model, $key, $value, $attributes)

src/Illuminate/Database/Eloquent/Casts/AsCollection.php

@@ -22,7 +22,7 @@ public function get($model, $key, $value, $attributes)
             {
                 $data = json_decode($attributes[$key], true);
 
-                return is_array($data) ? new Collection($data) : new Collection();
+                return is_array($data) ? new Collection($data) : null;
             }
 
             public function set($model, $key, $value, $attributes)

tests/Integration/Database/DatabaseCustomCastsTest.php

@@ -98,9 +98,11 @@ public function test_custom_casting_nullable_values()
         $this->assertEmpty($model->collection);
         $this->assertSame('', (string) $model->stringable);
 
+        $model->array_object = ['name' => 'John'];
         $model->array_object['name'] = 'Taylor';
         $model->array_object['meta']['title'] = 'Developer';
 
+        $model->array_object_json = ['name' => 'John'];
         $model->array_object_json['name'] = 'Taylor';
         $model->array_object_json['meta']['title'] = 'Developer';