==== Error ====
* mwversion: `1.38.0-wmf.2`
* reqId: `13f6f9b8-8502-4ff7-9473-081e4b5bf316`
* [[ https://logstash.wikimedia.org/app/dashboards#/view/AXFV7JE83bOlOASGccsT?_g=(time:(from:'2021-09-27T19:24:13.000Z',to:'2021-09-28T19:25:00.120Z'))&_a=(query:(query_string:(query:'reqId:%2213f6f9b8-8502-4ff7-9473-081e4b5bf316%22'))) | Find reqId in Logstash ]]
* [[ https://logstash.wikimedia.org/app/dashboards#/view/AXFV7JE83bOlOASGccsT?_g=(time:(from:now-30d,to:now))&_a=(query:(query_string:(query:'normalized_message:%22%5B%7BreqId%7D%5D%20%7Bexception_url%7D%20%20%20Error:%20Class%20'IP'%20not%20found%22'))) | Find normalized_message in Logstash ]]
```name=normalized_message
[{reqId}] {exception_url} Error: Class 'IP' not found
```
```name=exception.trace,lines=10
from /srv/mediawiki/private/PrivateSettings.php(100)
#0 /srv/mediawiki/php-1.38.0-wmf.2/includes/HookContainer/HookContainer.php(338): {closure}(User, string, boolean, integer)
#1 /srv/mediawiki/php-1.38.0-wmf.2/includes/HookContainer/HookContainer.php(137): MediaWiki\HookContainer\HookContainer->callLegacyHook(string, array, array, array)
#2 /srv/mediawiki/php-1.38.0-wmf.2/includes/HookContainer/HookRunner.php(2986): MediaWiki\HookContainer\HookContainer->run(string, array)
#3 /srv/mediawiki/php-1.38.0-wmf.2/includes/user/User.php(1693): MediaWiki\HookContainer\HookRunner->onPingLimiter(User, string, boolean, integer)
#4 /srv/mediawiki/php-1.38.0-wmf.2/includes/api/ApiStashEdit.php(195): User->pingLimiter(string)
#5 /srv/mediawiki/php-1.38.0-wmf.2/includes/api/ApiMain.php(1874): ApiStashEdit->execute()
#6 /srv/mediawiki/php-1.38.0-wmf.2/includes/api/ApiMain.php(853): ApiMain->executeAction()
#7 /srv/mediawiki/php-1.38.0-wmf.2/includes/api/ApiMain.php(824): ApiMain->executeActionWithErrorHandling()
#8 /srv/mediawiki/php-1.38.0-wmf.2/api.php(90): ApiMain->execute()
#9 /srv/mediawiki/php-1.38.0-wmf.2/api.php(45): wfApiMain()
#10 /srv/mediawiki/w/api.php(3): require(string)
#11 {main}
```
==== Impact ====
Large number of new errors (~300) spotted within a 15 minute window immediately following 1.38.0-wmf.2 promotion to group0. User impact unknown.
==== Notes ====
The deprecated IP class was recently removed as part of {T291008}. However, private settings is still referencing it.