Mix.Project.in_project/4 always produces recompilation warnings

[AndrewDryga]

Environment

elixir -v
Erlang/OTP 20 [erts-9.3.1] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]

Elixir 1.7.0-dev (73201ca) (compiled with Erlang/OTP 20)

Current behavior

This code would always produce warnings (It's run from within the umbrella app):

Mix.Project.in_project application_name, "apps/#{application_name}", fn _module ->
  Mix.Project.config()[:version] |> Version.parse!() |> IO.puts()
end

warning: redefining module Work.MyApp.Mixfile (current version defined in memory)
  /Users/andrew/Projects/work/talk/apps/myapp/mix.exs:1

0.1.0

Expected behavior

No warnings produced:

0.1.0

[josevalim]

Does it happen if you give a full path? Also, can you please provide a simple application that reproduces it? -- *José Valim* www.plataformatec.com.br Skype: jv.ptec Founder and Director of R&D

[AndrewDryga]

@josevalim it does reproduce with full path. For now, I found a workaround by setting Code.compiler_options(ignore_module_conflict: true) in the beginning of Mix task.

I can prepare sample all later this week.

[josevalim]

Ping.

[AndrewDryga]

@josevalim here is the repo to reproduce: https://github.com/AndrewDryga/elixir-issue-7741.
In umbrella app root run mix reproduce app2.

[josevalim]

@AndrewDryga the first argument here needs to be an atom: https://github.com/AndrewDryga/elixir-issue-7741/blob/master/apps/app1/lib/mix_task.ex#L6

but because we don't have a guard, you were not catching it. Pushing a guard soon!