User Profiles and External Identities
Explanation
XWiki stores user profiles as pages, one per user, whether the wiki checks their password itself or hands that decision over to an external identity provider.
The first time a provider authenticates a user the wiki has never seen, it creates a mirror profile for them — a synchronization can also create it in advance — and records on it the identity that profile stands for.
Every later login is matched on that pair, never on the user name. A profile therefore belongs to one identity at one provider: the same person arriving from anywhere else is someone the wiki has never seen, and gets a profile of their own.
FAQ
Does renaming a user break the link with their external identity?
No. The authenticator looks the profile up by the issuer and the subject recorded on it, so the user name it carries can change freely.
What happens when the same person signs in through two different providers?
Each provider gives them a different pair, so the wiki matches neither identity to the other and keeps one profile per identity.
