The default principal is "dev@localhost", if you run the system with the development profile (DEV) a user with sys-admin role will be created with that principal as username.
Tomcat/Apache integration for SAML will populate the ServletRequest#getRemoteUser with an empty string rather than null when not authenticated. This confuses Spring Security to think the user is authenticated but with an empty string as the principal name. This causes problems further down the line in Spring Security since an empty principal is not accepted.
To get around this we simply remove the SAML integration and rely solely on OAuth 2.0 for log in. An alternative would be to apply a servlet filter beforehand that would send null if the string is empty. But that has the downside of having different authentication mechanism for production and development. By using only OAuth 2.0 everywhere it works the same, and it is easier to troubleshoot.
Instead of storing the current user in the Wicket session, let Spring Security handle it. The CurrentUser implementation has been changed to look it up from there instead of the Wicket session.
Also enable, in addition to Shibboleth (pre-authenticated remote user), OAuth 2 login which removes the need for the locally modified web.xml with a faked remote user. The Docker Compose file has been updated to run a OAuth 2 container for this type of login.
