CreateContact treated any SetExternalUserID failure as "ext_id taken" and
fell through to the upsert, so a transient DB error created a second
contact with the same email. Now only a unique violation or a contact
deleted mid-flight falls through, other errors are returned.
SetExternalUserID also reports whether a row was actually updated, and
dbutil error checks use errors.As so wrapped errors match. Widget JWTs
with no email now store NULL instead of an empty string.
Abhinav Raut
2e203607e5