Challenge 1 / 2

You upgrade to Symfony 7.4, and you removed the extra.symfony.require setting. Later you run composer require symfony/mailer. What’s the most likely "surprise" that can happen?

Nothing changes — extra.symfony.require is just a comment for Symfony Flex, Composer completely ignores it.

Symfony will refuse to boot until you delete composer.lock, because Symfony reads extra.symfony.require at runtime.

Only require-dev packages will be affected; production packages always stay locked to 7.4 automatically.

Composer might install a mix of Symfony versions (like pulling in Symfony 8 for some packages), because nothing is forcing it to stick to 7.4 for new/transitive dependencies.

Rewatch the video