Deleting a developer client throws (My)SQL error

[Strubbl]

Issue details

i get the following error

500: Internal Server Error

An exception occurred while executing 'DELETE FROM wallabag_oauth2_clients WHERE id = ?' with params [1]: SQLSTATE[23000]: Integrity constraint violation: 1451 Cannot delete or update a parent row: a foreign key constraint fails (`wallabagv2`.`wallabag_oauth2_refresh_tokens`, CONSTRAINT `FK_19C9FB1245EB1234` FOREIGN KEY (`client_id`) REFERENCES `wallabag_oauth2_clients` (`id`))

instead of my developer client being deleted.

Environment

• wallabag version (or git revision) that exhibits the issue: 2.1 and 2.0.7
• How did you install wallabag? Via git clone or by downloading the package? git clone
• Last wallabag version that did not exhibit the issue (if applicable): i don't know
• php version: 5.6.24-0+deb8u1
• OS: debian jessie
• type of hosting (shared or dedicated): dedicated
• which storage system you choose at install (SQLite, MySQL/MariaDB or PostgreSQL): mysql

Steps to reproduce/test case

Please provide necessary steps for reproduction of this issue, or better the
reduced test case (without any external dependencies, if possible).

1. Go to developer menu
2. click on an existing client to open it
3. click the button "delete client"
4. get redirected to /developer/client/delete/1 page showing the above mentioned error