Question

In a CakePHP 2.2 app, I’m using class constants in a Model for some internal configuration. The following issue came up.

Short version:

Cake’s lazy class loading will not be triggered by a static call to the Model class.

If the first access to a Model in a Controller is

MyModel::SOME_CONST // fails

the class will be unknown. If any instance of the class is used before, it’s fine:

$this->MyModel->something();
MyModel::SOME_CONST // works

Not knowing about the details of the lazy loading implementation:

Question: Is this something that is impossible to fix? If so, why? How do I then best work around it in my App myself (wrap consts in a function)? Or is there a chance to improve the lazy loading so that it works with static access, too?

Long version with code:

In order to test the different cases, I made a small test App with 1 Model and 1 Controller:

Model/Post.php:

<?php
class Post extends AppModel {
    public $useTable = false; // Don't bother with a DB

    const FOO = "foo";

    public $bar = "bar";
}

Controller/PostsController.php:

<?php
class PostsController extends AppController {
    public function constant() {
        debug(Post::FOO);
    }

    public function variable() {
        debug($this->Post->bar);
    }

    public function variableFirst() {
        debug($this->Post->bar);

        debug(Post::FOO);
    }
}

Accessing the three controller actions through the browser, the different cases can now be tested.

1) accessing the Model constant (at /posts/constant):

Error: Class ‘AppModel’ not found

2) accessing the Model variable (at /posts/variable):

‘bar’

3) accessing the Model constant AFTER a variable (at /posts/variable):

‘bar’

‘foo’

Answer 1

lazyloading works with normal class calls as well as static calls IF you correctly approach it.

Correctly means, that you always have to App::uses() all used classes at the top of your file

for AppModel in a model file:

App::uses('AppModel', 'Model');

class Post extends AppModel {}

see the core files for details.