Provide hint when multiple config files are in-use

[joshtrichards]

Sometimes an admin makes a copy of their config/config.php in their config/ folder without being aware of Multiple config.php file support. If named appropriately we load it up and merge it (as designed).

This scenario comes up in the support forum and our Issues, leading to avoidable support requests and invalid bug reports.

Since this typically comes up when the other config files are backups, the main symptom is: "Why aren't my config changes active?"

Maybe we can indicate somehow/somewhere when multiple config files are in-use. The trick is it is a perfectly valid mode of operation. We don't want it to be an error or warning in our setup checks. It's possible to have it be an info I guess? We also don't want it so subtle that it's not visible to someone that (a) isn't aware of multiple config file support (b) is trying to figure out why their config changes are getting "overridden".

Alternatives and related:

• Encouraging the use of occ config:list system (to see live merged config) rather than direct config.php access
• Show active (merged) config in the UI (i.e. equivalent to occ config:list system).

[joshtrichards]

One thing we can do immediately is add a setup check if multiple version codes are specified. That's high probability indication that a backup config file is being loaded unintentionally.

It accounts for multiple queries I've fielded from admins having upgrade problems.

[joshtrichards]

Example occurrence: #32648