no-jinja-when

This rule checks conditional statements for Jinja expressions in curly brackets {{ }}. Ansible processes conditionals statements that use the when, failed_when, and changed_when clauses as Jinja expressions.

An Ansible rule is to always use {{ }} except with when keys. Using {{ }} in conditionals creates a nested expression, which is an Ansible anti-pattern and does not produce expected results.

Problematic Code

---
- name: Example playbook
  hosts: localhost
  tasks:
    - name: Shut down Debian systems
      ansible.builtin.command: /sbin/shutdown -t now
      when: "{{ ansible_facts['os_family'] == 'Debian' }}" # <- Nests a Jinja expression in a conditional statement.

Correct Code

---
- name: Example playbook
  hosts: localhost
  tasks:
    - name: Shut down Debian systems
      ansible.builtin.command: /sbin/shutdown -t now
      when: ansible_facts['os_family'] == "Debian" # <- Uses facts in a conditional statement.

Note

This rule can be automatically fixed using --fix option.