Clarify when variables and defaults are automatically included in nested directories

[mickael-carl]

It's not immediately obvious when reading the existing paragraph when variables in nested directories are included or not. This attempts to disambiguate it by explicitly calling out that anything not under main will not be included automatically, and by providing an additional negative example that illustrate exactly this behaviour.

Fixes #2994.

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[s-hertel]

I think the example helps. I had a few additional suggestions.

[s-hertel]

Suggested change

	In this example, no variables are included automatically. Instead, they should be included explicitly (e.g. using the ``vars_from`` in ``import_role`` statements).
	In this example, no variables are included automatically. Instead, they should be included explicitly (for example, using the ``vars_from`` argument in an ``import_role`` task).

[s-hertel]

The reporter is using the roles keyword, so I think we should add a note/warning that roles and dependencies cannot configure other entrypoints. (Also related: ansible/ansible#85876)

There's a note in the roles section (below, which links to this section) that says:

vars and defaults can also match to a directory of the same name and Ansible will process all the files contained in that directory. See Role directory structure for more details.

I think it should say "a directory named 'main'", instead.

[mickael-carl]

Could you clarify that first part? Are you suggesting to add a note that explicitly calls out that for instance vars_from in roles won't work? Basically also fixing ansible/ansible#85876 in this PR?

[s-hertel]

You can ignore or rephrase this suggestion, it's only tangentially related, but I had to read this line multiple times to understand it.

By 'other YAML files' I think it means non-main.yml/main.yaml/main files, and by 'some directories' I think it means tasks/handlers/defaults/vars.

To include files from outside of tasks/defaults/vars directories, include_tasks/import_tasks/include_vars must be used, not include_role/import_role. Handlers just can't be loaded from other directories since there's no mechanism (though an include_tasks handler in a standard location can run tasks from an arbitrary directory).

Suggested change

You can add other YAML files in some directories, but they won't be used by default. They can be included/imported directly or specified when using ``include_role/import_role``.

You can add YAML files named something other than ``main.yml`` in ``tasks/``, ``handlers/``, ``defaults/``, and ``vars/``, but they won't be used by default. They can be specified when using ``include_role``/``import_role``. Note that ``include_role`` and ``import_role`` do not support loading from other directories. You can include tasks/variables from arbitrary locations using ``include_tasks``/``import_tasks``/``include_vars``.

[mickael-carl]

Yeah sorry I didn't necessarily want to refactor this, there were just a bunch of trailing spaces and I figured I might as well remove them. I can definitely rephrase this though if this is something you think would improve this page 🙂