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How to Override any Part of a Bundle

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Warning: You are browsing the documentation for Symfony 2.8, which is no longer maintained.

Read the updated version of this page for Symfony 6.0 (the current stable version).

How to Override any Part of a Bundle

This document is a quick reference for how to override different parts of third-party bundles.


The bundle overriding mechanism means that you cannot use physical paths to refer to bundle's resources (e.g. __DIR__/config/services.xml). Always use logical paths in your bundles (e.g. @AppBundle/Resources/config/services.xml) and call the locateResource() method to turn them into physical paths when needed.


Routing is never automatically imported in Symfony. If you want to include the routes from any bundle, then they must be manually imported from somewhere in your application (e.g. app/config/routing.yml).

The easiest way to "override" a bundle's routing is to never import it at all. Instead of importing a third-party bundle's routing, simply copy that routing file into your application, modify it, and import it instead.


Assuming the third-party bundle involved uses non-service controllers (which is almost always the case), you can easily override controllers via bundle inheritance. For more information, see How to Use Bundle Inheritance to Override Parts of a Bundle. If the controller is a service, see the next section on how to override it.

Services & Configuration

If you want to modify the services created by a bundle, you can use service decoration.

If you want to do more advanced manipulations, like removing services created by other bundles, you must work with service definitions inside a compiler pass.

Entities & Entity Mapping

If a bundle defines its entity mapping in configuration files instead of annotations, you can override them as any other regular bundle configuration file. The only caveat is that you must override all those mapping configuration files and not just the ones you actually want to override.

If a bundle provides a mapped superclass (such as the User entity in the FOSUserBundle) you can override its attributes and associations. Learn more about this feature and its limitations in the Doctrine documentation.


Existing form types can be modified defining form type extensions.

Validation Metadata

Symfony loads all validation configuration files from every bundle and combines them into one validation metadata tree. This means you are able to add new constraints to a property, but you cannot override them.

To overcome this, the 3rd party bundle needs to have configuration for validation groups. For instance, the FOSUserBundle has this configuration. To create your own validation, add the constraints to a new validation group:

  • YAML
  • XML
# src/Acme/UserBundle/Resources/config/validation.yml
            - NotBlank:
                groups: [AcmeValidation]
            - Length:
                min: 6
                minMessage: fos_user.password.short
                groups: [AcmeValidation]

Now, update the FOSUserBundle configuration, so it uses your validation groups instead of the original ones.


Translations are not related to bundles, but to domains. That means that you can override the translations from any translation file, as long as it is in the correct domain.


Translation files are not aware of bundle inheritance. If you want to override translations from the parent bundle or another bundle, make sure that the bundle containing your translations is loaded after any bundle whose translations you're overriding. This is done in AppKernel.

Finally, translations located in app/Resources/translations will override all the other translations since those files are always loaded last.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.