Symfony version(s) affected

5.4

Description

From #44729

However, this issue made me realize that we probably forgot about the standalone app usage when implementing --symfony.

This option is used to determine if the installed shell completion script is still compatible with the complete command in Symfony (e.g. if we add a feature in 6.1 that requires a modification of the bash script). However, we currently set it using $application->getVersion(). This means that we're no longer checking Symfony versions when it's used by e.g. PHPstan. I have no idea how we can set this to the real symfony/console version here.
Maybe we should use a custom version scheme for completion? (e.g. one that we increase manually, independently from Symfony releases, whenever we break/change something?)

Possible fixes:

From @GromNaN:

+1 for adding a completion version that is incremented only when there is a breaking change. Like composer does for plugins.

From @stof:

yeah. either that or we should use \Composer\InstalledVersions::getVersion('symfony/console') to get the version (but then, that will be a pain when using a dev version of symfony/console).

Let's investigate how hard dev versions are here. That seems the most simple solution here.