drush migrate:status comes back with SQLSTATE [hy000] [2002] No such file or directory
I had this problem when upgrading/downgrading php to work with drush migrate. Check if the mysql.sock is right in php.ini:

First check what php.ini file is used in terminal:

php --ini


Then open the php.ini file and change/add:

pdo_mysql.default_socket=/Applications/MAMP/tmp/mysql/mysql.sock


or the mysql.sock you are using. To find your mysql socket in terminal use:

mysql_config --socket