Drupal 9.4 breaks configuration import; need to manually add mysql module

What is a configuration-managed site? Are we no longer supposed to be using Composer? (Found this thread after a Composer-based update caused my site to start throwing a 'missing module - mysql' error.)

Thank you for the tip on updating the config/sync/core.extension.yml file.

#11 worked for me when upgrading a d8 to d9 on Pantheon, thanks @Drumanuel

Configuration managed means you're exporting your configuration to yaml files using configuration sync or drush. This is completely unrelated to Composer.

To repeat what the top of the thread says, do not edit your configuration files manually. If you've gotten this error, you've made a mistake upgrading your Drupal site. You need to run install updates, run database updates, and then run configuration export.

If you got this error, you are running a configuration managed site and skipped exporting your configuration during the update. If you are exporting configuration to yaml files, you need to export your configuration every single time you install Drupal core or module updates.

@Greg Boggs, I totally understand your point, but having migrations from Drupal 8 to 9+ 10 or so on, doesn't mean you must have a step by step upgrade, and its - btw NOT NECESSARILY ( depends even on the platform and the solution ) The fix provided on #11 does provide a path to a full upgrade in/or some/many cases (which btw was recommend by Pantheon ). A config upgrade is key but when moving from older to newer version doesn't mean you have to go through the whole process if all goes Ok - under a full QA IMHO. The ability to manually edit a config file is what i consider a big plus! Oh, and once the site is consistent you can always export "drush cex" any new updates without compromising the existing configuration system.

Just a quick question on #16 you mention "6. Run drush deploy" - what version of drush are you using?

Thanks!

After composer update --with-all-dependencies ( Drupal 9.5.3->9.5.4) I got the Database Error (.... connection not found) when running the Database update. I cured it commenting out the Line namespace =...... in the file settings.php
With Drupal 9.5.3 it worked with: namespace' => 'Drupal\\Core\\Database\\Driver\\mysql'.