If I enabled some user plugins via Preferences -> Plugins and then
disabled all of them, an error occurred:
Jul 16 22:34:20 php[100]: PHP Fatal error: Uncaught TypeError: array_filter(): Argument #1 ($array) must be of type array, null given in /usr/share/webapps/tt-rss/classes/pref/prefs.php:1027
Jul 16 22:34:20 php[100]: Stack trace:
Jul 16 22:34:20 php[100]: #0 /usr/share/webapps/tt-rss/classes/pref/prefs.php(1027): array_filter()
Jul 16 22:34:20 php[100]: #1 /usr/share/webapps/tt-rss/backend.php(136): Pref_Prefs->setplugins()
Jul 16 22:34:20 php[100]: #2 {main}
Jul 16 22:34:20 php[100]: thrown in /usr/share/webapps/tt-rss/classes/pref/prefs.php on line 1027
Apparently the issue was elevated from a warning to an error in PHP 8.0
[1].
[1] https://php.watch/versions/8.0/internal-function-exceptions
f3aceb4648