Looking for alternative to set_fact + loop

Hi

I have a recurring challenge in our deployment, whereby we have a list
structure that is defaulted to a single (dict) item.
The challenge is that I would like to extend that in a way so that
additional items use the keys of the first item as their default.
I have gotten this work as in the example playbook:

I thought i had it:

vars:
  discos: "{{ discos_extra|map('combine', disco_default) }}"

But it is the wrong precedence, need to think about how to reverse that.

For example, given the default dictionary and the extra list

    defaults:
      name: default
      desc: standard
      foo: true
      bar: true

    extra:
      - name: foobar
        desc: dedicated
      - name: noli
        desc: discovery

the declaration below

    discos: "{{ [defaults] +
                [defaults]|product(extra)|map('combine')|list }}"

gives the expected list

  discos:
  - bar: true
    desc: standard
    foo: true
    name: default
  - bar: true
    desc: dedicated
    foo: true
    name: foobar
  - bar: true
    desc: discovery
    foo: true
    name: noli

Perfect!!!
V much appreciated