(Embedded mode) Erlang crashing when running tests

[jonator]

I'm getting the following logs appended to the end of output when running tests once I added the phoenix sync dep and ran it in embedded mode:

[os_mon] cpu supervisor port (cpu_sup): Erlang has closed
[os_mon] memory supervisor port (memsup): Erlang has closed

I use a test watcher and it also crashes, so it no longer works, which is a pain.

EDIT

Not positive if root cause is in phoenix_sync or electric.

Note: the repro below only kicked in when I added electric dep after phoenix_sync dep, but not sure if that's a signal of anything.

[jonator]

Some related googling:
vernemq/vernemq#137
https://elixirforum.com/t/os-mon-memory-supervisor-port-memsup-erlang-has-closed/34359

[jonator]

I managed to repro.

Should be able to clone this and run tests to see crash appended in logs:

https://github.com/jonator/phoenix_sync_test_crash

[magnetised]

hi @jonator. sorry you're having trouble.

I managed to repro.

Should be able to clone this and run tests to see crash appended in logs:

jonator/phoenix_sync_test_crash

Thanks for the repro. Appreciate you going the extra mile
There's a mismatch in your configuration which might be the problem.

In config/config.exs:

config :phoenix_sync,
  env: config_env(),
  mode: :embedded,
  repo: Swarm.Repo

the repo there doesn't match the repo configured in dev.exs which is PhoenixSyncTestCrash.Repo

When I fix that everything seems fine -- the tests fail but nothing crashes.

I don't see a crash without the fix either though, so not sure if we're seeing the same problem.

[jonator]

How much memory does your machine have? I have a 2021 M1 mac and I'm finding 16gb is no longer enough mid 2025. That could be a cause (have been having issues with this in other dev envs like Next.js)

[magnetised]

@jonator I have 48GiB on this machine. Electric isn't memory hungry though so you don't need much. Did you try the fix I mentioned above?

In config/config.exs: ... the repo there doesn't match the repo configured in dev.exs which is PhoenixSyncTestCrash.Repo