I see this warning every time after stale requests get removed from the "open requests" queue. This is done by the ConfirmAccount::runAutoMaintenance() function, which confirms for me that the line in the warning is accurate.

My guess for how to fix (I have very minimal PHP experience):
Replace line 27, if ( $path && file_exists( $path ) ) { with if ( $path && $repo->fileExists( $path ) ) {.

I can confirm this bug for Mediawiki 1.34.1 and ConfirmAccount REL1_34. Would be great to get this fixed for Mediawiki 1.35 LTS.

And I can confirm that this is happening in 1.36.1. Bueller?

Checking in here. Any new news? Still happening for us.

No news, otherwise they'd be listed here.

Still happening on

• MediaWiki 1.39.4 (c06e1c5) 00:11, 2 July 2023
• PHP 7.4.33 (apache2handler)
• MariaDB 10.5.19-MariaDB-0+deb11u2
• Confirm User Accounts – (4f1f849) 07:57, 20 June 2023

Warning: file_exists(): Unable to find the wrapper "mwstore" - did you forget to enable it when you configured PHP? in /..w/extensions/ConfirmAccount/includes/backend/ConfirmAccount.class.php on line 30

This time I got it when I did not check the acceptance for the Termos of Services when requesting an account and trying to submit the account request.