I have made a custom plugin that glues shibboleth with LS. Now one use can not log in, he gets "500: Internal Server Error CDbCommand failed to execute the SQL statement: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'full_name' cannot be null"

He has tried two different browsers, also in private mode. In a test page on the same server SB attribute displayName is shown as it should, i.e. data from SB login goes to PHP $_SERVER. Other people have no problem logging in. Any hints about how to debug this?

Put anything on full_name

return message is clear enough : full_name cannot be null

Just 20 minutes before your message I got this to work.

There was a non-empty name. For some reason the system failed after my plugin said setAuthSuccess($oUser). I deleted the user account and then the used logged in again (via shibboleth) and now everything works. I suppose that something very weird has happened in some version of LimeSurvey. I looked at DB also, and lime_users seemed to be OK. I still do not understand what happened.

Existing user ?

Yep. The user had been using the system for more than a year. About a week ago it just stopped to work; I suppose it happened after we had upgraded to 5.1.16+211020.

Sometghing related to plugin code , no ?

Hard to say. The plugin is quite simple and works for everyone else.