** (RuntimeError) cannot compile Plug because the :cowboy application is not available. Please ensure it is listed as a dependency before the plug one. about plug HOT 11 CLOSED

seemed to be a dep issue

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How did you solve this?

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/cc @ericmj

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i am a bit of noob here, but i switched phoenix to use the hex version, and then forked OAuth2Ex and changed it's dep for plug to 0.7.0

I think i had a dependency mismatch because pheonix relies on plug 0.7.0 and I was trying to build 0.6.0 ?

I did mix deps.clean and then a new mix do deps.get, compile and it compiled.
I think this was mostly user error, sorry for the issue.

Here is my updated mix.exs

defmodule Koncur.Mixfile do
  use Mix.Project

  def project do
    [ app: :koncur,
      version: "0.0.1",
      elixir: "~> 1.0.0-rc1",
      elixirc_paths: ["lib", "web"],
      deps: deps ]
  end

  # Configuration for the OTP application
  def application do
    [
      mod: { Koncur, [] },
      applications: [:cowboy, :phoenix, :logger, :postgrex, :ecto, :oauth2ex]
    ]
  end

  # Returns the list of dependencies in the format:
  # { :foobar, git: "https://github.com/elixir-lang/foobar.git", tag: "0.1" }
  #
  # To specify particular versions, regardless of the tag, do:
  # { :barbat, "~> 0.1", github: "elixir-lang/barbat" }
  defp deps do
    [
      {:cowboy, "~> 1.0.0"},
      {:phoenix, "0.4.0"},
      {:postgrex, ">= 0.0.0"},
      {:ecto, "~> 0.2.0"},
      {:oauth2ex, github: "j-mcnally/oauth2ex"}
    ]
  end
end

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Well, it may not be an user error because someone else reported it too. So if it happens again and you can provide a way to reproduce it, we would really appreciate it. :)

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@josevalim @ericmj I ran into this issue recently and am able to reproduce by simply symlinking the _build directory. The following steps can reproduce this issue (using Elixir 1.0.2):

mix new bug_finder
cd bug_finder

Set the dependencies in mix.exs to:

defp deps do
  [
    {:plug, "~> 0.8.2"},
    {:cowboy,  "~> 1.0"}
  ]
end

mkdir ../_build
ln -nsf ../_build ./_build
mix do deps.get, compile

Error returned is:

== Compilation error on file lib/plug/conn/adapter.ex ==
** (RuntimeError) cannot compile Plug because the :cowboy application is not available. Please ensure it is listed as a dependency before the plug one.
    lib/plug/conn/adapter.ex:4: (file)
    (elixir) lib/kernel/parallel_compiler.ex:97: anonymous fn/4 in Kernel.ParallelCompiler.spawn_compilers/8

==> plug
could not compile dependency plug, mix compile failed. You can recompile this dependency with `mix deps.compile plug` or update it with `mix deps.update plug`

(full output - https://gist.github.com/efatsi/ae8163a454b0400df05f)

If I haven't symlinked the _build directory the compile runs without issues.

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@efatsi what do you mean by symlinking the _build directory?

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And more importantly, why are you doing that? :)

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@josevalim I'm using capistrano to deploy an elixir app to a remote server, and in order to avoid rebuilding the gitignored _build directory on every deploy (since cap creates a fresh directory on every deploy), I attempted to symlink the _build directory with a shared location. I've since resorted to saving the _build directory out to a shared location and copying it in before compiling the app.

While trying to debug though I came across this issue and noticed you were looking for a way to reproduce.

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Ah, perfect @efatsi. Thanks for digging this up. I believe we don't really support symlinking _build, as you have noticed, as it contains symlinks inside of itself. Hopefully this was also the reason for @j-mcnally bug, as we haven't seen it in other forms lately.

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im not sure if my issue was symlinking or not. i dont think it was, i was new born baby new so i just assumed i had messed something up and eventually got it to work.

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