Molecule 3.0.0 introduced a bug at linting step (yamllint)

[fauust]

Issue Type

• Bug report

Molecule and Ansible details

❯ ansible --version && molecule --version                                                                
ansible 2.9.5
  config file = None
  configured module search path = ['/home/faust/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/faust/temp/venv/lib/python3.7/site-packages/ansible
  executable location = /home/faust/temp/venv/bin/ansible
  python version = 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0]
molecule 3.0.0
   ansible==2.9.5 python==3.7

Molecule installation method (one of):

• pip

Ansible installation method (one of):

• pip

Detail any linters or test runners used:

Desired Behavior

With molecule 2.22

❯ molecule --version                                                                                     
molecule, version 2.22
❯ molecule lint                                                                                          
--> Validating schema /home/faust/temp/test/molecule/default/molecule.yml.
Validation completed successfully.
--> Test matrix
    
└── default
    └── lint
    
--> Scenario: 'default'
--> Action: 'lint'
--> Executing Yamllint on files found in /home/faust/temp/test/...
Lint completed successfully.
--> Executing Flake8 on files found in /home/faust/temp/test/molecule/default/tests/...
Lint completed successfully.

Actual Behaviour

~/temp/test
❯ molecule lint                                                                                          
---
dependency:
  name: galaxy
driver:
  name: docker
lint:
  name: yamllint
platforms:
  - image: centos:7
    name: instance
provisioner:
  lint:
    name: ansible-lint
  name: ansible
verifier:
  lint:
    name: flake8
  name: testinfra

ERROR: Failed to pre-validate.

{'lint': ['must be of string type']}

[ssbarnea]

Not a bug, read #2560

[fauust]

Oups, sorry for that!

[dnorthup-ums]

@ssbarnea This is a bug, whether you like it or not. If you and your collaborators change a config file schema yet don't include anywhere in the config file a version number and expect people to spend 15 minutes Googling it because you can't be bothered to spit out a proper error, then you have introduced a bug.

[dnorthup-ums]

FYI: @tod-uma