[TwigBridge] Render a block via the #[Template] attribute

[smnandre]

Q	A
Branch?	7.2
Bug fix?	no
New feature?	yes
Deprecations?	no
Issues	Fix #...
License	MIT

The same way renderBlock was added in the AbstractController, and for the same reasons, this PR adds a block parameter on the Template attribute, used by the TemplateAttributeListener.

---

Example taken from the documentation

class ProductController extends AbstractController
{
    #[Template('product/index.html.twig')]
    public function index(): array
    {
        // ...

        // when using the #[Template] attribute, you only need to return
        // an array with the parameters to pass to the template (the attribute
        // is the one which will create and return the Response object).
        return [
            'category' => '...',
            'promotions' => ['...', '...'],
        ];
    }
}

With this PR

class ProductController extends AbstractController
{
    #[Template('product/index.html.twig', block: 'main')]
    public function index(): array
    {
        return [
            'category' => '...',
            'promotions' => ['...', '...'],
        ];
    }
}

---

🛟 Only problem here, i don't get how to test this properly..

Twig\Template is abstract, Twig\TemplateWrapper is final, and Environment::load() must return a TemplateWrapper..

I looked at the AbstractController tests but i don't find one covering the load->displayBlock / load->renderBlock.

[stof]

Make a test using an actual Twig instance, with a template that has a {% error %} tag in its top-level content (so that rendering the full template triggers an error). This way, you will be sure that it was not rendered in full.

[smnandre]

Thank you @stof!

Make a test using an actual Twig instance, with a template that has a {% error %} tag in its top-level content (so that rendering the full template triggers an error). This way, you will be sure that it was not rendered in full.

had to remove the error tag (kept some ERROR text)... as the parsing of the tag made compilation fail.

[stof]

ah sorry. We don't have the {% error %} in core, only the {% deprecated %} tag. I confused them.

[smnandre]

Thank you for the help ;)

[fabpot]

Thank you @smnandre.