wp-cli/wp-cli — pull request #369 by scribu (2013-03-29 02:56:47+00:00)
Title: Warning: Using a password on the command line interface can be insecure

That's the warning that's issued since MySQL 5.6, whenever you pass a password as a parameter to the `mysql` command.

This affects both the `db` subcommands, as well as the functional tests.