Including settings.php a second time and without same context can result in errors

Problem/Motivation

#3106531: Notify in Status Report that per-table database prefixes are no longer supported, and will throw errors in Drupal 10.0 introduces a function that includes settings.php again as part of requirements checks.

But that IMHO has two problems:

a) It is missing context, for example $class_loader. To use an alternative cache backend for the container cache, you afaik need to set the class loader explicitly, afaik that is still required. This is a fatal error now.
b) It loads those files a second time. They could do all kinds of things like messing with request data, define functions and what not that would cause problems.

Not quite sure what we can do? At least for the current/default connection, we can access \Drupal::database()->getConnectionOptions()['extra_prefix'], we could reduce the function to just checking that as a quickfix?

Other approaches would be to parse/preg match the settings file, but there can be includes to other files that define the database info. Does not seem viable

Remaining tasks

None

User interface changes

None

API changes

None

Data model changes

None

Release notes snippet

TBD