Distillery build error: Multiply defined module: 'Elixir.Collectable.Ecto.Adapters.SQL.Stream'

Trying to build a Phoenix 1.4 application via Distillery, and hitting this error:

==> Release failed with multiple errors:
    Multiply defined module: 'Elixir.Collectable.Ecto.Adapters.SQL.Stream'

I’ll note that this application is upgraded from Phoenix 1.3.4, and I did clean all the Elixir and Node deps and rebuild them prior to this run.

Google doesn’t seem to be much help with that error, my understanding is that it means the module is defined multiple times through more than 1 dependency. I don’t really know how to go about debugging/solving that issue though…

The verbose logs from the Distillery run are available here under the ‘Details’ of that post: Release build fails with 'No such module: asn1ct' error · Issue #627 · bitwalker/distillery · GitHub

Here’s my entire mix.exs if that helps any…

defmodule Poof.Mixfile do
  use Mix.Project

  def project do
    [
      app: :poof,
      version: "1.2.4+001",
      elixir: "~> 1.7",
      elixirc_paths: elixirc_paths(Mix.env),
      compilers: [:phoenix, :gettext] ++ Mix.compilers,
      start_permanent: Mix.env == :prod,
      aliases: aliases(),
      deps: deps()
    ]
  end

  # Configuration for the OTP application.
  #
  # Type `mix help compile.app` for more information.
  def application do
    [
      mod: {Poof.Application, []},
      extra_applications: [:asn1, :logger, :runtime_tools],
    ]
  end

  # Specifies which paths to compile per environment.
  defp elixirc_paths(:test), do: ["lib", "test/support"]
  defp elixirc_paths(_),     do: ["lib"]

  # Specifies your project dependencies.
  #
  # Type `mix help deps` for examples and options.
  defp deps do
    [
      {:phoenix, "~> 1.4.0"},
      {:phoenix_pubsub, "~> 1.0"},
      {:ecto_sql, "~> 3.0"},
      {:phoenix_ecto, "~> 4.0"},
      {:postgrex, "~> 0.14"},
      {:phoenix_html, "~> 2.10"},
      {:phoenix_live_reload, "~> 1.0", only: :dev},
      {:gettext, "~> 0.11"},
      {:plug_cowboy, "~> 2.0"},
      {:timex, "~> 3.4.0"},
      {:uuid, "~> 1.1"},
      {:basic_auth, "~> 2.2"},
      {:dynamic_server_manager, "~> 0.0.10"},
      {:distillery, "~> 2.0"},
      {:swoosh, "~> 0.13"},
      {:tesla, "~> 1.2.0"},
      {:jason, "~> 1.1.0"},
      {:mox, "~> 0.3", only: :test},
    ]
  end

  # Aliases are shortcuts or tasks specific to the current project.
  # For example, to create, migrate and run the seeds file at once:
  #
  #     $ mix ecto.setup
  #
  # See the documentation for `Mix` for more info on aliases.
  defp aliases do
    [
      "ecto.setup": ["ecto.create", "ecto.migrate"],
      "ecto.clean": ["ecto.drop", "ecto.setup"],
      "ecto.seed": ["run priv/repo/seeds.exs"],
      "ecto.reset": ["ecto.clean", "ecto.seed"],
      test: ["ecto.create --quiet", "ecto.migrate", "test"]
    ]
  end
end