How to avoid “Entities passed to the choice field must be managed. Maybe persist them in the entity manager?”

Question

1. Generated Entities from existing database
2. Generated CRUD controller

But it does not work with exception message:

Entit

Answer 1

Beware, this error can also be raised when using 'by_reference' => false, in your form type with relations that are not ManyToMany.
An unfortunate copy/paste put me in this situation.