ConsoleCompilerPass incompatible with symfony/console ≥ 8.1

Problem/Motivation

Disclaimer: This was found and fixed by an LLM. It also helped write this issue summary.

ConsoleCompilerPass::process() uses Definition::setTags() to register auto-discovered #[AsCommand] services:

$definition
  ->setAutowired(TRUE)
  ->setPublic(TRUE)
  ->setTags(['console.command' => []]);

setTags(['console.command' => []]) stores the tag as an empty array of instances ([]). Definition::addTag('console.command') stores it correctly as [[]] - an array containing one instance.

In symfony/console 8.0.x, AddConsoleCommandPass::process() iterates per-service and reads command names directly from the #[AsCommand]attribute. An empty tag instance list is harmless - the command is still registered.

In symfony/console 8.1, AddConsoleCommandPass::process() was refactored to iterate per-tag-instance:

foreach ($container->findTaggedServiceIds('console.command', true) as $id => $tags) {
    foreach ($tags as $tag) {   // $tags is [] — inner loop never runs
        $commandServices[$id]...
    }
}

With setTags(['console.command' => []]), $tags is [], the inner loop never executes, and the service is silently dropped from the command map. Auto-discovered #[AsCommand] commands are absent from vendor/bin/dr list with no error or warning.

Steps to reproduce

• Run the tests with Symfony 8.1: https://git.drupalcode.org/project/drupal/-/pipelines/869562
• Apply the fix and run again: https://git.drupalcode.org/project/drupal/-/pipelines/869568/
• Revert the upgrade and ensure it still passes: https://git.drupalcode.org/project/drupal/-/pipelines/869575

Proposed resolution

- ->setTags(['console.command' => []]);
+ ->addTag('console.command');

addTag() is compatible with both 8.0.x and 8.1.x.

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet