New in Symfony 5.3: Prototype Options

Contributed by Yonel Ceruto in #39913

The OptionsResolver component helps you configure objects with option arrays and is used by other components such as Form. In Symfony 5.3 we've improved it with prototype options, to resolve and validate a series of options repeatedly as part of another option.

Consider a connections option which accepts an array of database connections, each of them defining the same options (host, database, user and password). In Symfony 5.3, the best way to implement this is to use the new setPrototype() method to define the connection options as a prototype that can be repeated:

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$resolver->setDefault('connections', function (OptionsResolver $connResolver) {
    $connResolver
        ->setPrototype(true)
        ->setRequired(['host', 'database'])
        ->setDefaults(['user' => 'root', 'password' => null]);
});

Thanks to this configuration, you can now pass options like these:

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$resolver->resolve([
    'connections' => [
        'default' => [
            'host' => '127.0.0.1',
            'database' => 'symfony',
        ],
        'test' => [
            'host' => '127.0.0.1',
            'database' => 'symfony_test',
            'user' => 'test',
            'password' => 'test',
        ],
        // ...
    ],
]);