为什么php的empty()函数在CakePHP 2中不能像预期的那样处理$this->数据?

为了避免混淆，我重新写了这个问题

这是控制器:

<?php
class StaffController extends AppController{
    function test(){
        $this->data = $this->Staff->find( 'list' );
    }
}

这是整个视图:

<pre>
Count: <?php echo count( $this->data ) . "'n"; ?>
Empty: <?php echo ( empty( $this->data ) ? 'true' : 'false' ) . "'n"; ?>
Count: <?php echo count( $this->data ) . "'n"; ?>
<?php var_dump( $this->data ) ?>
</pre>

下面是渲染后的输出:

Count: 2
Empty: true
Count: 2
array(2) {
  [1]=>
  string(12) "Mock Staff 1"
  [2]=>
  string(12) "Mock Staff 2"
}

当count()和debug()显示已分配非空值时，为什么empty()返回True ?

这是一个CakePHP错误吗?PHP bug?？??

如果我用另一个变量代替$this->data:

function test(){
    $this->set( 'data', $this->Staff->find( 'list' ) );
}

和view:

<pre>
Count: <?php echo count( $data ) . "'n"; ?>
Empty: <?php echo ( empty( $data ) ? 'true' : 'false' ) . "'n"; ?>
Count: <?php echo count( $data ) . "'n"; ?>
<?php var_dump( $data ) ?>
</pre>

按预期运行:

Count: 2
Empty: false
Count: 2
array(2) {
  [1]=>
  string(12) "Mock Staff 1"
  [2]=>
  string(12) "Mock Staff 2"
}

人吗?