when you don't have any hosts in inventory, when running playbook there is only warning:
[WARNING]: provided hosts list is empty, only localhost is available. Note that the implicit localhost does not match 'all'
Is there a way to make that Error instead of Warning?
I find out that there is this parameter in ansible.cfg:
[inventory]
unparsed_is_failed = True
but it will only return error when there is no inventory file which you are trying to use. It didn't look into content.