Dispatch config transformation event during site install from configuration

Can we add a test for this. I'd love to fix it but I'm also scared of breaking it in the future.

I recently opened 📌 Config storage transformers do not get applied when installing Drupal from configuration Needs work for this, because I hit this with Config Overlay, as well. I only had the change in the "revert" step there, which seems to be sufficient at least according to Config Overlay's test coverage ;-). I left out the change in the initial import because as far as I can tell, there are no modules installed at that point anyway, so I felt like there's really no benefit to it. And ExcludedModulesEventSubscriber (which is the only transformer in code) will not have any effect on the initial install either, as far as I can tell. Just curious about the reasoning there, not at all opposed. In fact, if it doesn't break anything, it does seem more "correct" to do it in both cases. I guess if we do add another config subscriber in core it's nice to have that already affect the initial import and not just the "revert". In any case, will close my issue as duplicate.

RE #3: yes definitely needs tests! just didn't have enough time to add them.

RE #4: Yes, you are right, in the first steps there are no modules installed that could interact. However! You can add services via settings.php even from modules that are not yet installed. So we should definitely do it for both, which would mean the second import has to do much less if you add your modules services via settings.php to take effect in the first round. (which is what I think I will suggest people do for config split if they run into troubles with the non batched version or if they split their sync storage to smithereens against all recommendations)

And sorry for not having found your issue, and thanks for finding mine!

Ahh that's a neat idea, hadn't thought of that 👍 Thanks!

No worries about the issues, all good.