Ansible >= 12 (ansible-core >= 2.19) deprecates `stdout_callback=yaml`,
superceded by `callback_result_format=yaml`. There is a change in behaviour:
`callback_result_format` applies to output of both `ansible-playbook` _and_
`ansible`.
Tests that run `ansible` in a subprocess are now explicitly configured to use
json (even if they don't inspect that output yet) for more assert-able output
across all versions of Ansible.
Python 2.7 (distro package) and 3.6 (pyenv managed) jobs run on Ubuntu 22.04.
More recent Pythons (distro or Github provided) run on 24.04.
fixes#1256
Ansible tasks that run locally (e.g. `connection: local`, `delegate_to:
localhost`) must now specify their `ansible_python_interpreter`, typically as
`{{ ansible_playbook_python }}`; otherwise the system Python on the controller
(e.g. `/usr/bin/python`) is likely to be used and this is often outside the
version range supported by the Ansible verison under test. If this occurs then
the symptom is often a failure to import a builtin from
`ansible.module_utils.six.moves`, e.g.
```
fatal: [target-centos6-1]: FAILED! => changed=true
cmd:
- ansible
- -m
- shell
- -c
- local
- -a
- whoami
- -i
- /tmp/mitogen_ci_ansibled3llejls/hosts
- test-targets
delta: '0:00:02.076385'
end: '2025-04-17 17:27:02.561500'
msg: non-zero return code
rc: 8
start: '2025-04-17 17:27:00.485115'
stderr: |-
stderr_lines: <omitted>
stdout: |-
An exception occurred during task execution. To see the full traceback,
use -vvv. The error was: from ansible.module_utils.six.moves import
map, reduce, shlex_quote
```
By switching to block style (`|`) with clip (no `-` or `+`) the failure
messages don't require quoting and gain a single trailing newline. This causes
Ansible to print them as block style, when using the yaml stdout callback
plugin. As a result the values have one less layer of quoting and quote
escaping, making them much easier to read.
Alex Willmer