Why is Ansible not assigning the value from `stdout` and instead only the registered variable name?

This seems like a simple thing and I have done it many times before, but I started to notice some issues lately. Maybe I am just missing something dumb.

I have some pretty simply plays:

- name: Test register
  ansible.builtin.shell: echo something
  register: test_value

- name: Output test value
  ansible.builtin.debug:
    msg: "{{ test_value }}"

The results of these plays are:

TASK [foo/bar : Test register] *******************************************************************************
changed: [test_host] => {"changed": true, "cmd": "echo something", "delta": "0:00:00.002040", "end": "2023-05-24 05:49:06.107897", "msg": "", "rc": 0, "start": "2023-05-24 05:49:06.105857", "stderr": "", "stderr_lines": [], "stdout": "something", "stdout_lines": ["something"]}

TASK [foo/bar : Output test value] ***************************************************************************
ok: [test_host] => {
"msg": "test_value"
}

Ansible version:

ansible [core 2.13.3]
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/root/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.9/site-packages/ansible
  ansible collection location = /root/.ansible/collections:/usr/share/ansible/collections
  executable location = /usr/bin/ansible
  python version = 3.9.13 (main, Nov  9 2022, 13:16:24) [GCC 8.5.0 20210514 (Red Hat 8.5.0-15)]
  jinja version = 3.1.2
  libyaml = True

Why is it that I am only getting the registered variable name and not actually the stdout contents? This seems to also be inconsistent for me as well.

According Return Values

> Ansible modules normally return a data structure that can be registered into a variable ...

and Registering variables

> Registered variables may be simple variables, list variables, dictionary variables, or complex nested data structures. The documentation for each module includes a RETURN section describing the return values for that module.

in your case shell module – Execute shell commands on targets - Return Values.

> I am only getting the registered variable name and not actually the stdout contents?

As you can see from your output

"stdout": "something", "stdout_lines": ["something"]

you should get it via

- name: Output test value
  ansible.builtin.debug:
    var: test_value

- name: Output test value
  ansible.builtin.debug:
    var: test_value.stdout

For me it is not possible to produce a behavior where a minimal example playbook

---
- hosts: localhost
  become: false
  gather_facts: false

  tasks:

  - shell:
      cmd: "echo something"
    register: TEST

  - debug:
      var: TEST

  - debug:
      msg: "{{ TEST }}"

would just "msg": "TEST" instead of the expected

TASK [debug] **************************
ok: [localhost] =>
  TEST:
    changed: true
    cmd: echo something
    delta: '0:00:00.012925'
    end: '2023-05-24 12:00:00.856922'
    failed: false
    msg: ''
    rc: 0
    start: '2023-05-24 12:00:00.843997'
    stderr: ''
    stderr_lines: []
    stdout: something
    stdout_lines:
    - something

TASK [debug] **************************
ok: [localhost] =>
  msg:
    changed: true
    cmd: echo something
    delta: '0:00:00.012925'
    end: '2023-05-24 12:00:00.856922'
    failed: false
    msg: ''
    rc: 0
    start: '2023-05-24 12:00:00.843997'
    stderr: ''
    stderr_lines: []
    stdout: something
    stdout_lines:
    - something

> Why is it that I am only getting the ... variable name and not actually the ... contents?

I am able to produce your behavior via variable precedence and calling a minimal example playbook with --extra-vars to always win precedence

> In general, Ansible gives precedence to variables that were defined more recently, more actively, and with more explicit scope.

in your case

ansible-playbook debug.yml --extra-vars="test_value=test_value"

or in my case

ansible-playbook debug.yml --extra-vars="TEST=TEST"

resulting into an output of

TASK [debug] *****
ok: [localhost] =>
  msg: test_value

or

TASK [debug] *****
ok: [localhost] =>
  msg: TEST

but that would mean the description of your case is missing important information or is misleading.

Whatever, still, the content of the registered variable is displayed. It might look like the variable name but it is the content which is "the same as" the variable name.

If that is really the case you may need to search for such occurrences within your source code, in example ~/test$ grep -Rn test_value .