Steps to replicate the issue (include links if applicable):
- Open contribution of some user who is active in many projects, e.g. https://ru.wikipedia.org/w/index.php?title=User:Lvova&action=history
- Click on the icon next to the user name to open UserInfo pop-up
- https://ru.wikipedia.org/w/rest.php/checkuser/v0/userinfo API will be called
- Most likely, you will get a timeout error after some time because the request is too heavy
- You can try to open it again until it finally works
- Open your SUL info, e.g. https://meta.wikimedia.org/wiki/Special:CentralAuth/Putnik
- Order the list by the "Attached on" column
- There will be a lot of new accounts
What happens?:
A request to https://ru.wikipedia.org/w/rest.php/checkuser/v0/userinfo created local accounts in wikis you never visited, but the requested person has accounts in.
What should have happened instead?:
No new local accounts should be created.