When the PDO connection string results in failing connection, Moodle doesn't detect it and results in an incomphrensible error on attemtping to login:
Steps to reproduce:
- Add external database auth plugin
- Set the type to pdo and set the connection string to something which will cause it to fail, eg.:
- Set the host to 'pgsql:host=localhost;port=5432;dbname=enroltest;user= enroltest;password=enroltest'
- Don't set the username and password in the auth plugin settings
- Try to login with a junk username