[Console] Add a Compiler Pass to Easily Add Helpers

[chrisguitarguy]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	#15258
License	MIT
Doc PR	-

[linaori]

I find helpers extremely annoying on the console. There's virtually no way to get proper autocomplete. When people will start adding custom helpers, I fear it becomes a big mess where nobody knows what to use when and what's even available.

[Tobion]

I agree. The new console utilities like ProgressBar, ProgressIndicator and Table are not using the helper stuff anyway. So IMO we should deprecate the helper functionality in 3.1.

[ogizanagi]

Agree too. Plus you can already add helpers easily from the Application instance in app/console:

$kernel = new AppKernel($env, $debug);
$application = new Application($kernel);
$myHelper = ...; // Create the helper instance or get it from the Container
$application->getHelperSet()->set($myHelper);

The only benefit of such a compiler pass would be lazy-loading or third-party bundles being able to add helpers.
I don't think console helpers need lazy-loading due to what they generally achieve, and third party bundles can already add helpers if it is really needed through the trick you explained in #15258 (comment):

use Symfony\Bundle\FrameworkBundle\Console\Application as FrameworkApplication;
use Symfony\Component\Console\Application;
use Symfony\Component\HttpKernel\Bundle\Bundle;

class AppBundle extends Bundle
{
    /**
     * {@inheritdoc}
     */
    public function registerCommands(Application $application)
    {
        if ($application instanceof FrameworkApplication) {
            $container  = $application->getKernel()->getContainer()
            $application->getHelperSet()->set($container->get('your_helper'));
        }

        parent::registerCommands($application);
    }
}

EDIT: Forgot about my comment about any benefit: it won't even be lazy loaded anyway :/

[fabpot]

Closing for the reasons explained by @iltar and @Tobion