Copy and check elixir version in archives

Closes #2396

Author: José Valim

lib/mix/lib/mix/archive.ex

@@ -70,10 +70,11 @@ defmodule Mix.Archive do
 
   defp files_to_add(path, dir) do
     File.cd! path, fn ->
+      evsn = Path.wildcard(".elixir")
       ebin = Path.wildcard("ebin/*.{beam,app}")
       priv = Path.wildcard("priv/**/*")
 
-      Enum.reduce ebin ++ priv, [], fn(f, acc) ->
+      Enum.reduce evsn ++ ebin ++ priv, [], fn(f, acc) ->
         case File.read(f) do
           {:ok, bin} ->
             [{Path.join(dir, f) |> String.to_char_list, bin}|acc]

lib/mix/lib/mix/local.ex

@@ -15,7 +15,9 @@ defmodule Mix.Local do
   Append archives paths into Erlang code path.
   """
   def append_archives do
-    Enum.each(archives_ebin, &Code.append_path(&1))
+    archives = archives_ebin()
+    Enum.each(archives, &check_elixir_archive_vsn/1)
+    Enum.each(archives, &Code.append_path/1)
   end
 
   @doc """
@@ -49,4 +51,19 @@ defmodule Mix.Local do
   defp archives_ebin do
     Path.join(archives_path, "*.ez") |> Path.wildcard |> Enum.map(&Mix.Archive.ebin/1)
   end
+
+  defp check_elixir_archive_vsn(ebin) do
+    elixir = ebin |> Path.dirname() |> Path.join(".elixir") |> String.to_char_list
+    case :erl_prim_loader.get_file(elixir) do
+      {:ok, req, _} ->
+        unless Version.match?(System.version, req) do
+          archive = ebin |> Path.dirname() |> Path.basename
+          Mix.shell.error "warning: the archive #{archive} requires Elixir #{inspect req} " <>
+                          "but you are running on v#{System.version}"
+        end
+        :ok
+      :error ->
+        :ok
+    end
+  end
 end

lib/mix/lib/mix/tasks/archive.build.ex

@@ -45,7 +45,13 @@ defmodule Mix.Tasks.Archive.Build do
       input = opts[:input] ->
         input
       project ->
-        Mix.Project.app_path
+        path = Mix.Project.app_path
+        if elixir = Mix.Project.config[:elixir] do
+          File.write Path.join(path, ".elixir"), elixir
+        else
+          File.rm Path.join(path, ".elixir")
+        end
+        path
       true ->
         Mix.raise "Cannot create archive without input directory, " <>
           "please pass -i as an option"

lib/mix/test/mix/archive_test.exs

@@ -7,17 +7,18 @@ defmodule Mix.ArchiveTest do
 
   test "archive" do
     in_fixture "archive", fn ->
+      File.write ".elixir", "~> 1.0.0"
       Mix.Archive.create(".", "sample.ez")
       archive = 'sample.ez'
       assert File.exists?(archive)
+      assert has_zip_file?(archive, 'sample/.elixir')
       assert has_zip_file?(archive, 'sample/priv/not_really_an.so')
       assert has_zip_file?(archive, 'sample/ebin/Elixir.Mix.Tasks.Local.Sample.beam')
     end
   end
 
   defp has_zip_file?(archive, name) do
-    :zip.list_dir(archive)
-    |> elem(1)
-    |> Enum.find(&match?({:zip_file, ^name, _, _, _, _}, &1))
+    {:ok, files} = :zip.list_dir(archive)
+    Enum.find(files, &match?({:zip_file, ^name, _, _, _, _}, &1))
   end
 end

lib/mix/test/mix/tasks/archive_test.exs

@@ -5,13 +5,13 @@ defmodule Mix.Tasks.ArchiveTest do
 
   defmodule ArchiveProject do
     def project do
-      [ app: :archive, version: "0.1.0" ]
+      [app: :archive, version: "0.1.0", elixir: "~> 0.1.0"]
     end
   end
 
   defmodule ArchiveProject2 do
     def project do
-      [ app: :archive, version: "0.2.0" ]
+      [app: :archive, version: "0.2.0"]
     end
   end
 
@@ -22,7 +22,7 @@ defmodule Mix.Tasks.ArchiveTest do
 
     in_fixture "archive", fn() ->
       # Install it!
-      Mix.Tasks.Archive.Build.run []
+      Mix.Tasks.Archive.Build.run ["--no-elixir-version-check"]
       assert File.regular? "archive-0.1.0.ez"
 
       send self, {:mix_shell_input, :yes?, true}
@@ -32,10 +32,16 @@ defmodule Mix.Tasks.ArchiveTest do
       archive = tmp_path("userhome/.mix/archives/archive-0.1.0.ez/archive-0.1.0/ebin")
       assert to_char_list(archive) in :code.get_path
 
-      # List it!
+      # Load it!
       Mix.Local.append_archives
+      error = "warning: the archive archive-0.1.0 requires Elixir \"~> 0.1.0\" but you are running on v#{System.version}"
+      assert_received {:mix_shell, :error, [^error]}
+
+      # List it!
       Mix.Tasks.Local.run []
-      assert_received {:mix_shell, :info, ["mix local.sample # A local install sample"]}
+      info  = "mix local.sample # A local install sample"
+      assert_received {:mix_shell, :info, [^info]}
+
 
       Mix.Tasks.Archive.run []
       assert_received {:mix_shell, :info, ["* archive-0.1.0.ez"]}
@@ -60,12 +66,14 @@ defmodule Mix.Tasks.ArchiveTest do
         refute File.regular? tmp_path("userhome/.mix/archives/archive-0.1.0.ez")
       end
 
+      # Load it! No warnings because there is no :elixir in mix.exs.
       Mix.Local.append_archives
+      refute_received {:mix_shell, :error, [_]}
 
       # Remove it!
       send self, {:mix_shell_input, :yes?, true}
       Mix.Tasks.Archive.Uninstall.run ["archive-0.2.0.ez"]
-      
+
       # See reason for previous refutation.
       unless match? {:win32, _}, :os.type do
         refute File.regular? tmp_path("userhome/.mix/archives/archive-0.2.0.ez")