Invalid controller class: display

Question

I am trying to create a simple component. After installation of the component I get the following error message in the admin view:

An error has occurred.
0 Invalid controller class: display

I've already seen this question from another user but adding the <namespace>-tag didn't solve the error.

mycomponent.xml

<?xml version="1.0" encoding="utf-8"?>
<extension version="1.0.0" type="component">
    <name>MyComponent</name>
    <namespace path="src">Firecase\Component\MyComponent</namespace>
    <administration>
        <menu>MyComponent</menu>
        <files folder="admin">
            <folder>services</folder>
            <folder>src</folder>
            <folder>tmpl</folder>
        </files>
    </administration>
</extension>

DisplayController.php

<?php
namespace Firecase\Component\MyComponent\Administrator\Controller;

defined('_JEXEC') or die;

use Joomla\CMS\MVC\Controller\BaseController;

class DisplayController extends BaseController
{
    protected $default_view = 'mycomponent';

    public function display($cachable = true, $urlparams = array())
    {
        return parent::display($cachable, $urlparams);
    }
}
?>

provider.php

<?php
defined('_JEXEC') or die;

use Joomla\CMS\Dispatcher\ComponentDispatcherFactoryInterface;
use Joomla\CMS\Extension\ComponentInterface;
use Joomla\CMS\Extension\MVCComponent;
use Joomla\CMS\Extension\Service\Provider\ComponentDispatcherFactory;
use Joomla\CMS\Extension\Service\Provider\MVCFactory;
use Joomla\CMS\MVC\Factory\MVCFactoryInterface;
use Joomla\DI\Container;
use Joomla\DI\ServiceProviderInterface;

return new class implements ServiceProviderInterface
{
    public function register(Container $container): void {
        $container->registerServiceProvider(new MVCFactory('\\Firecase\\Component\\MyComponent'));
        $container->registerServiceProvider(new ComponentDispatcherFactory('\\Firecase\\Component\\MyComponent'));
        $container->set(
            ComponentInterface::class,
            function (Container $container) {
                $component = new MVCComponent($container->get(ComponentDispatcherFactoryInterface::class));
                $component->setMVCFactory($container->get(MVCFactoryInterface::class));

                return $component;
            }
        );
    }
}
?>

directory structure

com_mycomponent
├─ admin
│  ├─ services
│  │  └─ provider.php
│  ├─ src
│  │  ├─ controller
│  │  │  └─ DisplayController.php
│  │  ├─ model
│  │  └─ view
│  │     └─ mycomponent
│  │        └─ HtmlView.php
│  └─ tmpl
│     └─ mycomponent
│        └─ default.php
├─ site
│  └─ src
│     ├─ controller
│     ├─ model
│     └─ view
└─ mycomponent.xml

Answer 1

You have a lowercase 'f' in firecase, it should be Firecase. Namespaces in Joomla are very particular about having the first character of each level as an uppercase.

And you have a path of "src/", it is most likely you only need to use "src".

Answer 2

Try changing the following

<namespace path="src">Firecase\Component\MyComponent</namespace>

to

<namespace path="src/">Firecase\Component\MyComponent</namespace>

Adding the slash may fix the path attribute to the correct path.

Also check

<extension version="1.0.0" type="component">

Have you tried changing it to

<extension type="component" method="upgrade">

ADDED:

I ran into same problem. In my case some of Joomla's core methods were overridden. Try updating your Joomla in the Dashboard and then "Upload and Update".