display error message for empty/invalid login field values

[Peter Schober]

* sshabbir <sshabbir at bmj.com> [2018-07-24 23:02]:
> It seems there is no configuration for displaying an error message, to
> login.vm, when the user submits form with empty fields. How do I get error
> messages to display for empty fields.

You mean an error message that's (even more) specific to that case?

In my pretty-much-default IDP I do get an error message when just
submitting the login form with no username and no password:

  The username you entered cannot be identified.

The log has this to offer:

INFO [net.shibboleth.idp.authn.AbstractUsernamePasswordValidationAction:187]
- Profile Action ValidateUsernamePasswordAgainstLDAP: No username
available within UsernamePasswordContext

-peter