How to use a custom type correctly in symfony?

@raphael_tillman 

Using a custom type in Symfony involves several steps. Here's a general outline of how to go about it:

1. Define the Custom Type: Create a new class for your custom type, typically extending the AbstractType class provided by Symfony. Override the configureOptions method to define any options related to your custom type. Override the buildForm method to define how the form fields should be built.
2. Register the Custom Type: Register your custom type as a service in your Symfony application. If using Symfony 4 or higher, you can define this in the services.yaml file. Otherwise, you can define it in the services.xml or services.php file. Alternatively, you can use the services.autowire or services.autoconfigure configuration options in Symfony 5 or higher to automatically register your custom type without needing to define it as a service explicitly.
3. Use the Custom Type: Once registered, you can use your custom type in your forms or as a field in an entity. If using a form, add the custom type by calling add('field_name', CustomType::class) inside your form builder, where field_name is the field you want to associate with the custom type. If using an entity field, specify the custom type in your entity class by adding @ORMColumn(type="custom") annotation above the field declaration.
4. Optional: Customize the Custom Type: You can further customize the behavior of your custom type by overriding other methods inside the class, such as getParent (to extend an existing type), getBlockPrefix (to define a unique form type name), or finishView (to modify the rendering of the form fields).

Remember to clear the Symfony cache (php bin/console cache:clear) after defining or modifying your custom type to ensure that Symfony recognizes the changes.

It's worth noting that the above steps provide a general outline, and the exact implementation may vary depending on your specific use case. Symfony documentation can provide more detailed information on each step.