Single string not cast to list of strings in role argument_spec validation

[egdoc]

Summary

During module parameters validation, if a value must be a list and a single string is provided, the value is turned into a list with that string as the only element, due to this code:

ansible/lib/ansible/module_utils/common/validation.py

Lines 390 to 410 in 667526c

	def check_type_list(value):
	"""Verify that the value is a list or convert to a list
	A comma separated string will be split into a list. Raises a :class:`TypeError`
	if unable to convert to a list.
	:arg value: Value to validate or convert to a list
	:returns: Original value if it is already a list, single item list if a
	float, int, or string without commas, or a multi-item list if a
	comma-delimited string.
	"""
	if isinstance(value, list):
	return value
	if isinstance(value, string_types):
	return value.split(",")
	elif isinstance(value, int) or isinstance(value, float):
	return [str(value)]
	raise TypeError('%s cannot be converted to a list' % type(value))

Although the validation passes, the function doesn't seem to be applied when validating a role.

Issue Type

Bug Report

Component Name

Role Argument Spec Validation

Ansible Version

ansible [core 2.16.6]
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/doc/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.12/site-packages/ansible
  ansible collection location = /home/doc/.ansible/collections:/usr/share/ansible/collections
  executable location = /usr/bin/ansible
  python version = 3.12.3 (main, Apr 17 2024, 00:00:00) [GCC 14.0.1 20240411 (Red Hat 14.0.1-0)] (/usr/bin/python3)
  jinja version = 3.1.3
  libyaml = True

Configuration

CONFIG_FILE() = /etc/ansible/ansible.cfg
EDITOR(env: EDITOR) = /usr/bin/vim

OS / Environment

Fedora 40

Steps to Reproduce

meta/argument_specs.py

---
argument_specs:
  main:
    short_description: test_role description.
    options:
      test_option:
        type: list
        elements: str
        required: true

tasks/main.yml

---
- name: Print var
  ansible.builtin.debug:
    msg: '{{ test_option }}'

test_playbook.yml

---
- name: Test
  hosts: localhost
  roles:
    - role: test_role
      test_option: singlestring

Playbook run:

ansible-playbook test_playbook.yml

PLAY [Test] **************************************************************************************************************************************************************************

TASK [Gathering Facts] ***************************************************************************************************************************************************************
ok: [localhost]

TASK [test_role : Validating arguments against arg spec 'main' - test_role description.] *******************************************************************
ok: [localhost]

Expected Results

TASK [test_role: Print var] ******************************************************************************************************************************************************
ok: [localhost] => {
    "msg": [ 
              "singlestring",
    ]
}

Actual Results

TASK [test_role: Print var] ******************************************************************************************************************************************************
ok: [localhost] => {
    "msg": "singlestring"
}

Code of Conduct

• I agree to follow the Ansible Code of Conduct

[ansibot]

Files identified in the description:

• lib/ansible/playbook/role/__init__.py

If these files are incorrect, please update the component name section of the description or use the component bot command.

[flowerysong]

Role argument validation is just validation and cannot change the content of variables, This is unlikely to change since it would introduce even more complexity to the already complex variable model, so default is just for documentation and the existing type validators only guarantee that it can be converted to the type, not that it is actually that type. See #81575 for the planned addition of strict validators, which is evidently on hold until data tagging lands.

[sivel]

Duplicate of #78889

[egdoc]

Got it, thanks.