Passwordless mysql

I’m making some changes to a local development environment, specifically to evaluate whether or not TiDB is a suitable drop in for MySQL. It would make my feedback loops a little bit shorter if, in this environment, I could just not specify a password and have oned not supply one. Doing so gives errors about failing to authenticate.

I’d like to do something like this:

DB = [ BACKEND = "mysql",
       SERVER  = "",
       PORT    = "4000",
       USER    = "root",
       PASSWD  = null,
       DB_NAME = "opennebula" ]

Is there a way or will oned bomb out unless it has a password?

I should add: Setting PASSWD = "" also fails (but works fine from mysql -h -u root -P 4000 etc)