Use dotted YAML variables file in Ansible - variables

Question

I'm trying to achieve the following using Ansible:
Define a YAML file with some variables in the dotted format inside it (variables.yml)
database.hosts[0]: "db0"
database.hosts[1]: "db1"
database.hosts[2]: "db2"
foo.bar: 1
foo.baz: 2
Load the variables in variables.yml by using the include_vars module in my playbook (playbook.yml) and print them in a tree structure
- hosts: all
gather_facts: not
tasks:
- name: "Loading vars"
run_once: true
include_vars:
file: 'variables.yml'
- name: "Testing"
debug:
msg: "{{ foo }}"
- name: "Testing"
debug:
msg: "{{ database }}"
Running this results in the following error:
fatal: [host0]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: 'foo' is undefined\n\nThe error appears to be in '.../playbook.yml': line 9, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n - name: \"Testing\"\n ^ here\n"}
Which makes it clear that each property in the YAML file has been loaded as a separate property and not as properties within two trees rooted in database and foo.
Of course, the playbook works as expected if I specify the properties as follows:
database:
hosts:
- "db0"
- "db1"
- "db2"
foo:
bar: 1
baz: 2
However, I need the YAML variables file to be in the dotted format instead of in the classic indented format. Is there any way to achieve this? E.g.: a module different from include_vars or some configuration that I can add to the ansible.cfg file? I have already tried to use hash_behaviour=merge, but that didn't help.

Answer 1

Q: "I need the YAML variables file to be in the dotted format instead of in the classic indented format. Is there any way to achieve this?"
A: No. It's' not possible. See Creating valid variable names.