In a nutshell I have an error in production that I don’t have in development while using the same versions for all the software involved.
Environment
- Elixir version (elixir -v):
$ ./bin/tasks remote
Erlang/OTP 23 [erts-11.1.6] [source] [64-bit] [smp:1:1] [ds:1:1:10] [async-threads:1]
Interactive Elixir (1.11.3) - press Ctrl+C to exit (type h() ENTER for help)
- Domo version (mix deps | grep domo | head -1):
$ mix deps | grep domo | head -1
* domo 1.0.1 (Hex package) (mix)
- TypedStruct version (mix deps | grep typed_struct | head -1):
$ mix deps | grep typed_struct | head -1
* typed_struct 0.2.1 (Hex package) (mix)
I run it in development and in production with the docker image from the Phoenix releases docs:
https://hexdocs.pm/phoenix/releases.html#containers
Versions used to build the docker image:
ELIXIR_VERSION=1.11.3
ERLANG_OTP_VERSION=23.2.2
ALPINE_VERSION=3.12.1
Actual behavior
The error from a production release:
09:20:32.459 | error | module=gen_server function=error_info/7 line=943 | GenServer #PID<0.2551.0> terminating
app_1 | ** (UndefinedFunctionError) function Mix.Compilers.ApplicationTracer.trace/2 is undefined (module Mix.Compilers.ApplicationTracer is not available)
app_1 | Mix.Compilers.ApplicationTracer.trace({:alias_reference, [line: 45], NaiveDateTime}, #Macro.Env<aliases: [], context: nil, context_modules: [TypeIt.Progress], file: "/app/lib/type_it/lib/progress.ex", function: nil, functions: [{Kernel, [!=: 2, !==: 2, *: 2, ...]}], lexical_tracker: #PID<3.316.0>, line: 42, macro_aliases: [], macros: [{Domo, ...}, {...}], module: TypeIt.Progress, requires: [...], ...>)
app_1 | (elixir 1.11.3) src/elixir_env.erl:36: :elixir_env."-trace/2-lc$^0/1-0-"/3
app_1 | (elixir 1.11.3) src/elixir_env.erl:36: :elixir_env.trace/2
app_1 | (elixir 1.11.3) lib/macro.ex:1440: Macro.do_expand_once/2
app_1 | (elixir 1.11.3) lib/macro.ex:1610: Macro.expand_until/2
app_1 | (domo 1.0.1) lib/domo/type_spec_matchable/remote_type.ex:11: Domo.TypeSpecMatchable.RemoteType.expand/2
app_1 | (domo 1.0.1) lib/domo/type_contract.ex:642: Domo.TypeSpecMatchable.Any.match_spec?/3
app_1 | (tasks 0.1.0) lib/type_it/lib/progress.ex:42: TypeIt.Progress.TypeChecker.__field_error/1
The Typed Struct code:
defmodule TypeIt.Progress do
use Domo
@all_states %{
backlog: "Backlog",
todo: "Todo",
doing: "Doing",
pending: "Pending",
done: "Done",
archived: "Archived",
}
@states Map.keys(@all_states)
typedstruct do
field :state, :backlog | :todo | :doing | :pending | :done | :archived
field :title, String.t()
field :since, NaiveDateTime.t()
end
def default(), do: new_for!(:todo)
def next_state(:backlog), do: :todo
def next_state(:todo), do: :done
def next_state(:done), do: :todo
def new_for!(state), do: new!(state: state, title: @all_states[state], since: NaiveDateTime.utc_now())
def new_for!(state, since: since), do: new!(state: state, title: @all_states[state], since: since)
def new_for!(state, title: title), do: new!(state: state, title: title, since: NaiveDateTime.utc_now())
def states() do
@states
end
def all() do
@all_states
end
end
Expected behavior
In production is throwing the reported error that crashes the app, but in development it works ok.
Summary
Looking to this line in the logs:
Mix.Compilers.ApplicationTracer.trace({:alias_reference, [line: 45], NaiveDateTime},
It seems the error is related with using:
field :since, NaiveDateTime.t()
but I don’t get why I don’t have the same error in development, when using the same exact versions of Elixir, Phoenix, OTP, and Domo library 
Any ideas?
They should do whatever expansion they need at compile time and remove the runtime expand calls.
