TYPO3 Core

Right now InstallUtility::install triggers a AfterPackageActivationEvent for each extension after processExtensionSetup ran.

In Composer Mode, the CLI command extension:setup is used to ensure extensions are ready for use.
In this case, there currently is no event triggered, as InstallUtility::processExtensionSetup is called directly. Triggering the AfterPackageActivationEvent does not make sense in this context, since Composer packages are always active.

However, some extensions may need so do additional stuff in order to be usable, (e.g. set up additional files in other places than "fileadmin").

That's why I'd like to have a new event AfterExtensionSetupEvent (similar to AfterPackageActivationEvent), which is executed at the end of InstallUtility::processExtensionSetup. Extensions can listen to that event and run the actions they need to do. Also it will work for both Composer and Non-Composer mode, further improving the idea of the command extension:setup to set up all extensions.