yedit fails on a key that is a list of dict, can it be done?

I have a yaml file witch contains a instance of a key with dicts.

Here's an example:

INSTANCES:
  - NAME: hosttype1
    HOST_NAME: mysevername1
  - NAME: hosttype2
    HOST_NAME: myservername2
  - NAME: hosttype2
    HOST_NAME: myservername3

And the code i tried in my role to change all NAME's and HOST_NAME's are like this:

- name: Update property file {{ environment_env_property_file }} 
yedit:
  src: "{{ environment_env_property_file }}"
  state: present
  edits:
- key: INSTANCES.NAME[0]
  value: "CM01"
- key: INSTANCES.NAME[0].HOST_NAME
  value: "ap-2001c.domain.net"
- key: INSTANCES.NAME[1]
  value: "BP01"
- key: INSTANCES.NAME[1].HOST_NAME
  value: "ap-2002c.domain.net"
- key: INSTANCES.NAME[2]
  value: "BP01"
- key: INSTANCES.NAME[2].HOST_NAME
  value: "ap-2003c.domain.net"

Error from ansible

An exception occurred during task execution. To see the full traceback, use -vvv. The error was: main.YeditException: Unexpected item type found while going through key path: INSTANCES.NAME[0] (at key: NAME)

So what is the correct way to change the list of dictionaries?

Or should it be?

- key: INSTANCES[0].NAME
  value: "hosttype1"
- key: INSTANCES[0].HOST_NAME
  value: "myservername1"
- key: INSTANCES[1].NAME
  value: "hosttype2"
- key: INSTANCES[1].HOST_NAME
  value: "myservername2"
- key: INSTANCES[2].NAME
  value: "hosttype3"
- key: INSTANCES[2].HOST_NAME
  value: "myservername3"

After just dropping the source code from yedit.py under my local Ansible /library, for a property_file.yml with content of

INSTANCES:
  - NAME: hosttype1
    HOST_NAME: mysevername1
  - NAME: hosttype2
    HOST_NAME: myservername2
  - NAME: hosttype2
    HOST_NAME: myservername3

a minimal example playbook

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

  vars:

    property_file: property_file.yml

  tasks:

    - name: Update property file {{ property_file }}
      yedit:
        src: "{{ property_file }}"
        state: present
        edits:
          - key: INSTANCES[0].NAME
            value: "CM01"
          - key: INSTANCES[0].HOST_NAME
            value: "ap-2001c.example.net"
          - key: INSTANCES[1].NAME
            value: "BP01"
          - key: INSTANCES[1].HOST_NAME
            value: "ap-2002c.example.net"
          - key: INSTANCES[2].NAME
            value: "BP01"
          - key: INSTANCES[2].HOST_NAME
            value: "ap-2003c.example.net"

will result into a changed YML file with content of

INSTANCES:
- HOST_NAME: ap-2001c.example.net
  NAME: CM01
- HOST_NAME: ap-2002c.example.net
  NAME: BP01
- HOST_NAME: ap-2003c.example.net
  NAME: BP01

If that's the Use Case, changing all key value pairs, template or copy might be simpler.

---

If the Use Case is to change a subset only, a few list elements from a huge list , a minimal example playbook with loop and based on index

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

  vars:

    NEW_INSTANCES:
      - TYPE: CM01
        FQDN: ap-2001c.example.net
      - TYPE: BP01
        FQDN: ap-2002c.example.net

    property_file: property_file.yml

  tasks:

    - name: Update property file {{ property_file }}
      yedit:
        src: "{{ property_file }}"
        state: present
        edits:
          - key: "INSTANCES[{{ ansible_loop.index0 }}].NAME"
            value: "{{ item.TYPE }}"
          - key: "INSTANCES[{{ ansible_loop.index0 }}].HOST_NAME"
            value: "{{ item.FQDN }}"
      loop: "{{ NEW_INSTANCES }}"
      loop_control:
        extended: true

will result into an output of

TASK [Update property file property_file.yml] ****************************
ok: [localhost] => (item={'TYPE': 'CM01', 'FQDN': 'ap-2001c.example.net'})
ok: [localhost] => (item={'TYPE': 'BP01', 'FQDN': 'ap-2002c.example.net'})

and a file content of

INSTANCES:
- HOST_NAME: ap-2001c.example.net
  NAME: CM01
- HOST_NAME: ap-2002c.example.net
  NAME: BP01
- HOST_NAME: myservername3
  NAME: hosttype2

Please take note in this second example the module in question, yedit expect the key to edit as string:

def main():
...
    module = AnsibleModule(
        argument_spec=dict(
...
            key=dict(default='', type='str'),
            value=dict(),
...

Therefore one can't just write INSTANCES[ansible_loop.index0].HOST_NAME. Instead it is necessary to write "INSTANCES[{{ ansible_loop.index0 }}].HOST_NAME" which resolves to INSTANCES[0].HOST_NAME. Also "INSTANCES[ {{ ansible_loop.index0 }} ].HOST_NAME" would not work as that resolves to INSTANCES[ 0 ].HOST_NAME.