[make:crud|voter] generate classes with final keyword

[jrushlow]

• introduces 2 new configuration values:

  • generate_final_classes: Defaults to true - When true, all non-entity classes generated by MakerBundle will be final.
  • generate_final_entities: Defaults to false - When true, all entity classes generated by MakerBundle will be final.

• introduces an internal ClassData object that represents all of the meta data needed to generate a class from a template. It combines parts of ClassNameDetails & UseStatementGenerator, while adding logic to generate a class declaration conditionally including the finalkeyword &extends` class.

• ClassData is configured by TemplateComponentGenerator to handle root_namespace, generate_final_classes, & generate_final_entities if passed as a template class_data variable to Generator::createClass(). The idea being we don't have to modify the constructor for the "non-internal" Generator::class

• reduces the complexity of our .tpl.php templates. The ClassData object is accessible from within the templates (Crud & Voter for now). $class_data->getClassDeclaration() generates final class SomeClass extends XyzClass

• To keep the PR's "reviewable" this PR only adds the new functionality for make:crud & make:voter. To be implemented in additional makers in subsequent PR's.

• fix test fixtures to use final

• update this description to include all of the proposed changes

fixes #1536

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I think instead of one massive PR, we will merge this PR first to include make:voter & make:crud -> create subsequent PR's for makers that touch entities (1 pr) and the rest of the makers (1 pr). I say this because this PR is actually adding a handful of new features (mostly internal) in order to generate final classes.

[seb-jean]

Thanks Jesse

[jrushlow]

Hmm. So I don't think we can final classes by default without causing confusion amongst the consumers of MakerBundle. I'm not 100% on my thought process here, but doctrine orm is using lazy ghosts by default - atleast that's what we're doing in the DoctrineBundleRecipe -> https://github.com/symfony/recipes/blob/8cba886fb716a49e654845980cba33e211288a9b/doctrine/doctrine-bundle/2.9/config/packages/doctrine.yaml#L11

Like the failed tests for this PR, wouldn't we trigger logic exceptions everywhere in userland code similar to:

Symfony\Component\VarExporter\Exception\LogicException: Cannot generate lazy ghost: class "Symfony\Bundle\MakerBundle\Tests\tmp\current_project\src\Entity\User" is final.

if all the generated entities were final, we'd end up forcing the user to either a) remove the final keyword everytime they make:user|entity|security etc... || b) set orm.enable_lazy_ghost_objects: false. Both of those options are not viable.

I think the only way we can implement the final keyword for generated entities would be on a opt-in basis with a --is-final flag. We should be able to implement the final keyword for non-entity classes by default.

If I'm missing something obvious - please let me know.. Thoughts @symfony/mergers ?