New in Symfony 7.2: Lazy Choice Loader

Contributed by Yonel Ceruto in #52503

The EntityType field defined by Symfony Forms allows you to represent all the values stored for some Doctrine Entity via a <select> HTML element or a collection of radio buttons or checkboxes. It extends the ChoiceType field, one of the most versatile (and complex) types in Symfony Forms.

The biggest drawback of EntityType is that it can cause performance issues when rendering an entity with many values. The common solution is to create an autocomplete field using a combination of PHP and JavaScript code.

In Symfony 7.2 we're simplifying this with the introduction of a LazyChoiceLoader that implements an on-demand choice loading strategy. You can use it in your form types via the choice_lazy option:

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$formBuilder->add('user', EntityType::class, [
    'class' => User::class,
    'choice_lazy' => true,
]);

Internally, this loader keeps the choice list empty until the values are needed (avoiding unnecessary database queries). When form values are provided or submitted, it retrieves and caches only the necessary choices.

The front-end part needed to display the choices dynamically to the user is still not provided. To achieve this, you can use the autocomplete field from Symfony UX.