PHP Autoloading With class_exists confusion - php

Question

I am working on an application where i have quite a lot of PHP Classes and i write classes like below
<?php
if(!class_exists('AClass1')){
class AClass1{
}
}
?>
and likewise i have around 400 classes and also i use a php autoloader script
https://github.com/varunsridharan/php-autoloader
Along with a classmap generator
https://github.com/varunsridharan/php-classmap-generator
So what happens is that when i write a condition like below
if(class_exists('AClass1')){
// Some Code To RUN
}
In the above code if the class AClass1 not exists then it autoloads via class_exists function which is good for me
But when i write a code like this in a file called aclass1.php
<?php
if(!class_exists('AClass1')){
class AClass1{
}
}
?>
and if that file is loaded via above if condition then after loading the file it still loops into autoloader instead it just should register the class
so whats the good way to avoid looping into autoloader even if the file inside class source
Never use class_exists when registering a class
use class_exists('CLASSNAME',false) to avoid looping inside autoloader

Answer 1

I wrote a simple test to see if a include loop might exists:
test.php
<?php
// The simpliest autoloader
spl_autoload_register(function ($class) {
include __DIR__ . '/Hello.php';
});
if (class_exists('Hello')) {
$hello = new Hello();
exit('class exists');
} else {
exit('class does not exists');
}
Hello.php
<?php
if (!class_exists('Hello')) {
class Hello {
}
}
I put both these files in the same folder. Then I run:
php test.php
There is no error or loop. It simply prints:
class exists
But frankly, you do not need the class_exists check in your class file at all if you're using an autoloader. The autoloader would only be called if the class is not already exists in the current environment. So unless you would manually include a class file after it is autoloaded, you'll be fine.
If for some strange reason you might have that, use include_once instead of include.