** (Mix) Could not start application os_mon
I'm on the develop branch (been for years now). In December, updated routinely and then first this warning (I shall explain why this may be relevant later):
==> prometheus_phoenix Compiling 1 file (.ex) warning: Phoenix.Controller.action_name/1 defined in application :phoenix is used by the current application but the current application does not depend on :phoenix.
Then, "systemctl start pleroma" fails with:
Dec 27 03:25:33 vps221183 systemd[1]: Started Pleroma social network. Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.205 [info] Application fast_sanitize exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.254 [info] Application fast_html exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.255 [info] Application nimble_pool exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.256 [info] Application quack exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.256 [info] Application poison exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.256 [info] Application tesla exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.256 [info] Application comeonin exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: 03:25:37.257 [info] Application runtime_tools exited: :stopped Dec 27 03:25:37 vps221183 elixir[89215]: ** (Mix) Could not start application os_mon: could not find application file: os_mon.app Dec 27 03:25:39 vps221183 systemd[1]: pleroma.service: Main process exited, code=exited, status=1/FAILURE
So, I looked for 'os_mon' and:
[pleroma@vps221183 pleroma]$ git blame mix.exs | grep os_mon
29d80b39f2 (Alex Gleason 2021-12-15 16:17:11 -0500 82) :os_mon,
Commit 29d80b39 is "Add Phoenix LiveDashboard". I know I should just back it out, but it's too involving for someone who does not know Elixir. For now, I patched out :os_mon from mix.exs and it allowed me to start.