[web2py] SQLFORM and read-only references

[howesc]

It seems that in the latest version of web2py (1.91.6 and today's trunk) 
that if you have a table (say auth_user), with a format string, and then you 
refer to it in another table as read-only like:
  Field('updated_by', 'reference '+auth.settings.table_user_name,
        default=auth.user_id,update=auth.user_id,writable=False),

when the form is rendered we see 'None' rather than the format of the 
referenced table.  I can adjust the read-only field to have a represent 
like:
  Field('created_by', 'reference '+auth.settings.table_user_name,
        default=auth.user_id, writable=False,
        represent=lambda x: auth_user_table[x].first_name + " " + \
          auth_user_table[x].last_name+" ("+str(auth_user_table[x].id)+")" \
          if x else None),
(which matches my format string on my auth_user table).  Is this a 
regression, or was i making broken assumptions previously?

thanks,

christian