LiveView genserver crash errors not showing on elixir 19

Questions & Help Questions
,
1

I’m in the process of upgrading from Elixir 1.18.4 to 1.19.5, and I’ve run into an issue where errors inside LiveView are no longer appearing in the logs.

For example, if I introduce an obvious error like this in a LiveView:

def handle_event("update_email", params, socket) do
  {:ok, user} = socket.assigns.current_scope.user
  # intentionally incorrect pattern match

  {:noreply, socket}
end

I would expect an error like the one below to be logged, but nothing appears - even though the UI shows a ‘Cannot connect to server’ message and refreshes, indicating the GenServer has crashed:

[error] GenServer #PID<0.869.0> terminating
** (MatchError) no match of right hand side value:

I’ve confirmed this is specific to my project. I created a fresh Phoenix project, and the error appears in the logs as expected there.

The project is fairly large, but configuration-wise it’s mostly vanilla. I do use Sentry for error tracking in production, but the issue persists even after removing it.

At this point, I’m not sure where to look next. Has anyone run into something similar or have any ideas on what might be causing this?

Thanks in advance for any guidance!

2

Ah, it was the handle_otp_reports flag in my dev.exs:

# Include OTP and SASL logs
config :logger,
  handle_otp_reports: false,
  handle_sasl_reports: false,
  truncate: :infinity

Which is fair enough :sweat_smile: I guess something changed between Elixir 1.18 and 1.19 with it (hopefully useful for any future readers!)