Autoloader resulting in class not found

Question

I am trying to include an autoloader in my wordpress project. More specifically, I am developing a plugin that contains a Classes/ directory of all my classes. I want these classes to be accessible by namespace to my wordpress project root and children files/folders.

I feel like my composer.json should take care of the autoloader implementation, although I am still getting a Class not found fatal error. Has anyone else run into this issue? I appreciate any suggestions in advance!

This is what I tried so far:

./composer.json

  {
        "autoload": {
            "psr-4": {
                "Classes\\": "wp-content/plugins/example-plugin/Classes"
            }
        },
        "require": {}
    }

then...

composer install

./index.php (in wordpress root)

require_once('./vendor/autoload.php');

$foo = new \Classes\MyService();

var_dump($foo); //Fatal error: Uncaught Error: Class 'Classes\MyService' not found
die();

./wp-content/plugins/example-plugin/Classes/MyService.php

namespace Classes;

class MyService {

Answer 1

Yes, indeed, composer should take care of your dependencies and autoloading. Your configuration also is correct. Let's walk through a check list:

Does your environment look like this?

$ tree
.
├── composer.json
├── composer.phar
├── index.php
├── vendor
│   ├── autoload.php
│   └── composer
│       ├── autoload_classmap.php
│       ├── autoload_namespaces.php
│       ├── autoload_psr4.php
│       ├── autoload_real.php
│       ├── autoload_static.php
│       ├── ClassLoader.php
│       ├── installed.json
│       └── LICENSE
└── wp-content
    └── plugins
        └── example-plugin
            └── Classes
                └── MyService.php

Does your composer.json look like this?

$ cat composer.json
{
    "name": "my/project",
    "authors": [
        {
            "name": "My Name",
            "email": "my@na.me"
        }
    ],
    "autoload": {
       "psr-4": {
           "Classes\\": "wp-content/plugins/example-plugin/Classes"
       }
    },
    "require": {}
}

Does your implementation look like this?

$ cat wp-content/plugins/example-plugin/Classes/MyService.php
<?php
namespace Classes;

class MyService {
}

Finally, does your index look like this?

$ cat index.php
<?php

require_once('./vendor/autoload.php');

$foo = new \Classes\MyService;

var_dump($foo);

If your answer is "Yes" to all of these, have you refreshed your autoloader?

$ composer dump-autoload

If your answer is "Yes", then create a new directory, download composer.phar, run php composer.phar init, copy and paste this answer's files into that directory, and try again.

If that works, then diff this with your implementation. My guess is, if you get this far, you have a stray character -- possibly Unicode white space -- hiding in one of your files.