Error rendering template: can only concatenate list (not "_AnsibleTaggedStr") to list

[richm]

Summary

Version: ansible-lint 25.6.1 using ansible-core:2.19.0 ansible-compat:25.6.0 ruamel-yaml:0.18.14 ruamel-yaml-clib:0.2.12

https://github.com/linux-system-roles/cockpit/blob/main/tasks/setup-dnf.yml#L44 and context looks like this:

- name: Ensure full package list is installed
  command:
    argv: "{{ __argv }}"
  when: "'cockpit-*' in __pkgs"
  register: __cockpit_dnf
  changed_when: "'Nothing to do.' not in __cockpit_dnf.stdout_lines"
  vars:
    __excludes: "{{ ['--exclude'] | product(__cockpit_packages_exclude | union(cockpit_packages_dyn_exclude)) | flatten }}"
    __argv: "{{ ['dnf', '-y', 'install', 'cockpit-*'] + __excludes }}"
    __pkgs: "{{ __cockpit_packages[cockpit_packages]
      if cockpit_packages in __cockpit_package_types
      else cockpit_packages }}"

Note that cockpit_packages_dyn_exclude is a list, and __cockpit_packages_exclude is a list.

The latest ansible-lint gives this error:

jinja[invalid]: Error rendering template: can only concatenate list (not "_AnsibleTaggedStr") to list

tasks/setup-dnf.yml:44:13 Task/Handler: Ensure full package list is installed

everything is a list - I can't figure out what is wrong here

Issue Type

• Bug Report

OS / ENVIRONMENT

ansible-lint 25.6.1 using ansible-core:2.19.0 ansible-compat:25.6.0 ruamel-yaml:0.18.14 ruamel-yaml-clib:0.2.12

• ansible installation method: pip
• ansible-lint installation method: pip

STEPS TO REPRODUCE

git clone https://github.com/linux-system-roles/cockpit
cd cockpit
ansible-lint

Desired Behavior

Ansible-lint either should not complain, or it should tell me what is wrong

Actual Behavior

jinja[invalid]: Error rendering template: can only concatenate list (not "_AnsibleTaggedStr") to list

tasks/setup-dnf.yml:44:13 Task/Handler: Ensure full package list is installed

[richm]

ping - I have a similar case in the kdump system role

jinja[invalid]: Error rendering template: can only concatenate list (not "UndefinedMarker") to list
tests/kdump/tests_default_reboot.yml:36:17 Task/Handler: Check parameters in conf file

jinja[invalid]: Error rendering template: can only concatenate list (not "UndefinedMarker") to list
tests/kdump/tests_default_reboot.yml:88:17 Task/Handler: Check parameters in conf file

here is where those variables are defined: https://github.com/linux-system-roles/kdump/blob/main/tests/tests_default_reboot.yml#L25C1-L32C78

    - name: See if el9 or later, or el7 or el8
      set_fact:
        is_el9: "{{
          ansible_facts['distribution'] in ['RedHat', 'CentOS', 'Fedora']
          and ansible_facts['distribution_major_version'] | int >= 9 }}"
        is_el7_or_el8: "{{
          ansible_facts['distribution'] in ['RedHat', 'CentOS']
          and ansible_facts['distribution_major_version'] | int in [7, 8] }}"

and this is one of the places where they are used: https://github.com/linux-system-roles/kdump/blob/main/tests/tests_default_reboot.yml#L40 loop: "{{ params + (is_el9 | ternary(el9_params, not_el9_params)) }}"

AFAICT, this should always evaluate to a list, and nothing here should be undefined

Please Help

[richm]

please, can someone take a look at this?