Uninstallation of matrix_synapse_reverse_proxy_companion_service fails

[Michael-Hollister]

Describe the bug
The matrix-synapse-reverse-proxy-companion role fails its uninstallation task if you have previously installed Synapse on your server, and decide to change to Conduit or Dendrite

A workaround i'm currently using is to delete matrix-synapse-reverse-proxy-companion.service manually in /etc/systemd/system/ before I run just setup-all for setting up Conduit/Dendrite, but my understanding is that the matrix-synapse-reverse-proxy-companion uninstallation task should take care of removing itself from the service directory.

To Reproduce

Starting from the default vars.yml example file with updates to default entries + adding ansible_ssh_private_key_file. Ensure that matrix_homeserver_implementation is Synapse and that workers are enabled so that the matrix-synapse-reverse-proxy-companion service is created.

1. If not ran yet: just roles
2. just setup-all
3. just start-all
4. just stop-all
5. Change in vars.yml the field matrix_homeserver_implementation to conduit or dendrite
6. just setup-all

The error output after running the last command:

TASK [custom/matrix-synapse-reverse-proxy-companion : Ensure matrix-synapse-reverse-proxy-companion.service is stopped] *****
task path: /matrix_test2/roles/custom/matrix-synapse-reverse-proxy-companion/tasks/setup_uninstall.yml:10

...

fatal: [<SERVER>]: FAILED! => changed=false 
  invocation:
    module_args:
      daemon_reexec: false
      daemon_reload: true
      enabled: false
      force: null
      masked: null
      name: matrix_synapse_reverse_proxy_companion_service_stat
      no_block: false
      scope: system
      state: stopped
  msg: 'Could not find the requested service matrix_synapse_reverse_proxy_companion_service_stat: host'

Error Cause
If the service matrix-synapse-reverse-proxy-companion.service still exists in /etc/systemd/system/, then this error will happen. As mentioned earlier, if you remove this file manually before running just setup-all, then this task will pass.

Matrix Server:

• OS: Rocky Linux RockyLinux 8.6 x64
• Architecture: amd64

Ansible:

• where you run Ansible: On the Matrix server, standard installation
• what version of Ansible you're running:

ansible [core 2.13.3]
  config file = /matrix_test2/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  8 2022, 17:21:43) [GCC 8.5.0 20210514 (Red Hat 8.5.0-15)]
  jinja version = 3.1.2
  libyaml = True