Sonata Admin: non-existent service "security.authorization_checker"

I am trying to set up a simple CMS using Sonata Admin Bundle. I use composer to add sonata-project/admin-bundle and sonata-project/doctrine-orm-admin-bundle to an empty git repository, then follow the rest of the directions on https://sonata-project.org/bundles/admin/3-x/doc/getting_started/installation.html

Now I visit http://localhost/admin/dashboard, which the instructions say should give me a blank dashboard. Instead, I get a ServiceNotFoundException, stating:

The service "sonata.admin.menu.group_provider" has a dependency on a non-existent service "security.authorization_checker".

Is there a bundle or configuration that I need to install/add in order to fix this?

===

When I run bin/console debug:container security.authorization_checker I get the following output:

In CheckExceptionOnInvalidReferenceBehaviorPass.php line 86:

The service "sonata.admin.menu.group_provider" has a dependency on a non-existent service "secur ity.authorization_checker".

===

Here is config/packages/sonata_admin.yaml:

sonata_block:
  blocks:
    # enable the SonataAdminBundle block
    sonata.admin.block.admin_list:
      contexts: [admin]

... and here is config/services.yaml:

parameters:
    locale: 'en'

services:
    # default configuration for services in *this* file
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.
        autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.

    # makes classes in src/ available to be used as services
    # this creates a service per class whose id is the fully-qualified class name
    App\:
        resource: '../src/*'
        exclude: '../src/{DependencyInjection,Entity,Migrations,Tests,Kernel.php}'

    # controllers are imported separately to make sure services can be injected
    # as action arguments even if you don't extend any base controller class
    App\Controller\:
        resource: '../src/Controller'
        tags: ['controller.service_arguments']

    # add more service definitions when explicit configuration is needed
    # please note that last definitions always *replace* previous ones

... and here is my bundles.php:

return [
    Symfony\Bundle\FrameworkBundle\FrameworkBundle::class => ['all' => true],
    Doctrine\Bundle\DoctrineBundle\DoctrineBundle::class => ['all' => true],
    Doctrine\Bundle\MigrationsBundle\DoctrineMigrationsBundle::class => ['all' => true],
    Symfony\Bundle\MakerBundle\MakerBundle::class => ['dev' => true],
    Doctrine\Bundle\FixturesBundle\DoctrineFixturesBundle::class => ['dev' => true, 'test' => true],
    Sensio\Bundle\FrameworkExtraBundle\SensioFrameworkExtraBundle::class => ['all' => true],
    Symfony\Bundle\TwigBundle\TwigBundle::class => ['all' => true],
    Symfony\Bundle\WebProfilerBundle\WebProfilerBundle::class => ['dev' => true, 'test' => true],
    Sonata\DoctrineORMAdminBundle\SonataDoctrineORMAdminBundle::class => ['all' => true],
    Symfony\Bundle\SecurityBundle\SecurityBundle::class => ['all' => true],
    Sonata\BlockBundle\SonataBlockBundle::class => ['all' => true],
    Knp\Bundle\MenuBundle\KnpMenuBundle::class => ['all' => true],
    Sonata\AdminBundle\SonataAdminBundle::class => ['all' => true],
    Sonata\Doctrine\Bridge\Symfony\SonataDoctrineBundle::class => ['all' => true],
    Sonata\Form\Bridge\Symfony\SonataFormBundle::class => ['all' => true],
    Sonata\Twig\Bridge\Symfony\SonataTwigBundle::class => ['all' => true],
];

Solution

You need to install symfony security. And maybe flex, if you don't already have it.

composer require symfony/flex
composer require security

That will automatically install and configure the bundle for you.