There is no extension able to load the configurati

Question

Similar question has been here a few times already but unfortunately I wasn't able to find the help needed in there.

I am trying to create a custom extension class in Symfony (3.1). I am following the cookbook [1,2] but no matter what I try, I get the error

InvalidArgumentException in YamlFileLoader.php line 404: There is no extension able to load the configuration for "czechnology_tools" (in [path_to_project]\src\Czechnology\ToolsBundle\DependencyInjection/../Resources/config\holidays.yml). Looked for namespace "czechnology_tools", found none

classCzechnologyToolsExtension:

<?php

namespace Czechnology\ToolsBundle\DependencyInjection;

// use ...

class CzechnologyToolsExtension extends Extension
{
    public function load(array $configs, ContainerBuilder $container)
    {
        $configuration = new Configuration();
        $config = $this->processConfiguration($configuration, $configs);
        $loader = new Loader\YamlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
        $loader->load('holidays.yml');
    }
}

and the corresponding Configuration.php in the same directory:

<?php

namespace Czechnology\ToolsBundle\DependencyInjection;

// use ...

class Configuration implements ConfigurationInterface
{
    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root('czechnology_tools');

        $rootNode
            ->children()
                ->scalarNode('calendar')->defaultValue('default')->end()
            ->end()
        ;

        return $treeBuilder;
    }
}

In the YAML file, I currently just have dummy content, trying to get it to work at all. holidays.yml:

czechnology_tools:
    calendar: foo

If I try to debug in console, I get this:

$ bin/console config:dump-reference czechnology_tools
# Default configuration for extension with alias: "czechnology_tools"
czechnology_tools:
    calendar:             default

So it seems to be that the extension is set correctly, with the correct alias. However, I still cannot get over the exception. Any hints?

Answer 1

My guess is that somewhere is your bundle architecture, there is a typo (maybe intentional, a bundle class named differently than the extension, ...).

First, run bin/console debug:config, in order to see if your bundle appears with a different alias of the one you're trying to use, you should have an output containing a line that looks like:

CzechnologyToolsBundle | [the good alias]

If it doesn't appear at all, add the following to your bundle class:

namespace Czechnology\ToolsBundle;

use Czechnology\ToolsBundle\DependencyInjection\CzechnologyToolsExtension;

class CzechnologyToolsBundle extends Bundle
{
    public function getContainerExtension()
    {
        return new CzechnologyToolsExtension();
    }
}

Plus, add the following method to your bundle extension:

/**
 * {@inheritdoc}
 */
public function getAlias()
{
    return 'czechnology_tools';
}

Hope it solves the issue.