PHP - Fatal error: Class not found

What was happened

I am working on adding new features to a web system written in PHP.

After sometime of coding and make it works on the local environment, I need to deploy the code to development servers for testing.

But everything stops working, with a really mysterious message

Fatal error: Class ... not found

What!!!

I double-check the folder, the class. They are there!

The cause

Since the error message must have something to do with php autoload, I take an investigation, and finally found the cause!

For php autoload to work, the file name and the class name must exactly match.

Let see an example

// filename: app/Models/Userorder.php
namespace App\Models;

class UserOrder { }

// in another file
// instantiate the class
new \App\Models\UserOrder(); 

Pay attention to the file name Userorder.php

to instantiate the UserOder class, php will try to load the file app/Models/UserOrder.php first but since there's no UserOrder.php file (the file was Userorder.php), it fails and throws the fatal error.

Fatal error: Class UserOrder not found

Because my local development machine was Windows, and windows is case-insensitive, it can load the file normally.

Solution

Just change the file name

$ mv app/Models/Userorder.php app/Models/UserOrder.php

Hope everyone doesn't waste the time to that kind of bug.