Installation fails during configuration (Symfony 4.4 - flex)

[Garfield-fr]

$ composer require friendsofsymfony/oauth-server-bundle

The installation fails when configuring with the following output:

Executing script cache:clear [KO]
 [KO]
Script cache:clear returned with error code 1
!!
!!  In ArrayNode.php line 224:
!!
!!    The child node "db_driver" at path "fos_oauth_server" must be configured.
!!
!!
!!
Script @auto-scripts was called via post-update-cmd

Installation failed, reverting ./composer.json to its original content.

[patrickbussmann]

Did you followed the documentation for setting up the bundle?

The child node "db_driver" at path "fos_oauth_server" must be configured.

https://github.com/FriendsOfSymfony/FOSOAuthServerBundle/blob/master/Resources/doc/index.md#step-5-configure-fosoauthserverbundle

Follow the setup instructions please.
First you need to create the entities for access token, ... and then you need to set up the configuration.

See comment here #639 (comment)