Unhandled gen_statem Timout Event

[aj-foster]

Elixir version

1.14.2 on OTP 25.2

Database and Version

PostgreSQL 14.1

Postgrex Version

0.17.0

Current behavior

Hello there 👋🏼

In #643, Postgrex began using gen_statem in Postgrex.SimpleConnection. There appears to be an unhandled timeout event.

When I run tests for my application (which uses Oban — which uses NOTIFY), the following error occurs:

** (FunctionClauseError) no function clause matching in Postgrex.SimpleConnection.handle_event/4
    (postgrex 0.17.0) lib/postgrex/simple_connection.ex:340: Postgrex.SimpleConnection.handle_event(:timeout, nil, :no_state, %Postgrex.SimpleConnection{...})
    (stdlib 4.2) gen_statem.erl:1428: :gen_statem.loop_state_callback/11
    (stdlib 4.2) proc_lib.erl:240: :proc_lib.init_p_do_apply/3

The documentation for gen_statem lists three timeout event types:

timeout | {timeout, Name :: term()} | state_timeout

However, I only see a handler for {:timeout, :backoff}.

If it's useful, I'm using Oban 2.14.2, though I believe the problem is internal to Postgrex and gen_statem.

Expected behavior

I believe this type of :timeout event is normal (and should be handled), but I'm too unfamiliar with gen_statem to know for sure.

❤️