Automatically recompile on outdated elixir version

Author: José Valim

CHANGELOG.md

@@ -3,6 +3,7 @@
 * Enhancements
 
 * Bug fixes
+  * [Mix] Automatically recompile on outdated Elixir version and show proper error messages
 
 * Deprecations
   * [Kernel] `%` for sigils is deprecated in favor of `~`

lib/mix/lib/mix/deps.ex

@@ -261,7 +261,7 @@ defmodule Mix.Deps do
   end
 
   def format_status(Mix.Dep[status: { :elixirlock, _ }]),
-    do: "the dependency is built with an out-of-date elixir version, run `#{mix_env_var}mix deps.get`"
+    do: "the dependency is built with an out-of-date elixir version, run `#{mix_env_var}mix deps.compile`"
 
   defp dep_status(Mix.Dep[app: app, requirement: req, opts: opts, from: from]) do
     info = { app, req, Dict.drop(opts, [:dest, :lock, :env, :build]) }
@@ -311,20 +311,6 @@ defmodule Mix.Deps do
   def available?(Mix.Dep[status: { :unavailable, _ }]),  do: false
   def available?(Mix.Dep[]), do: true
 
-  @doc """
-  Checks if a dependency is out of date, also considering its
-  lock status. Therefore, be sure to call `check_lock` before
-  invoking this function.
-
-  Out of date dependencies are fixed by simply running `deps.get`.
-  """
-  def out_of_date?(Mix.Dep[status: { :lockmismatch, _ }]), do: true
-  def out_of_date?(Mix.Dep[status: :lockoutdated]),        do: true
-  def out_of_date?(Mix.Dep[status: :nolock]),              do: true
-  def out_of_date?(Mix.Dep[status: { :elixirlock, _ }]),   do: true
-  def out_of_date?(Mix.Dep[status: { :unavailable, _ }]),  do: true
-  def out_of_date?(Mix.Dep[]),                             do: false
-
   @doc """
   Formats a dependency for printing.
   """

lib/mix/lib/mix/deps/fetcher.ex

@@ -7,7 +7,7 @@
 defmodule Mix.Deps.Fetcher do
   @moduledoc false
 
-  import Mix.Deps, only: [format_dep: 1, check_lock: 2, out_of_date?: 1, available?: 1, ok?: 1]
+  import Mix.Deps, only: [format_dep: 1, check_lock: 2, available?: 1, ok?: 1]
 
   @doc """
   Fetches all dependencies.
@@ -57,6 +57,12 @@ defmodule Mix.Deps.Fetcher do
     end
   end
 
+  defp out_of_date?(Mix.Dep[status: { :lockmismatch, _ }]), do: true
+  defp out_of_date?(Mix.Dep[status: :lockoutdated]),        do: true
+  defp out_of_date?(Mix.Dep[status: :nolock]),              do: true
+  defp out_of_date?(Mix.Dep[status: { :unavailable, _ }]),  do: true
+  defp out_of_date?(Mix.Dep[]),                             do: false
+
   defp do_finalize({ all_deps, { apps, new_lock } }, old_lock) do
     # Let's get the loaded versions of deps
     deps = Mix.Deps.loaded_by_name(apps, all_deps)

lib/mix/lib/mix/tasks/deps.check.ex

@@ -51,6 +51,7 @@ defmodule Mix.Tasks.Deps.Check do
     { Enum.reverse(not_ok), Enum.reverse(compile) }
   end
 
+  defp compile?(Mix.Dep[status: { :elixirlock, _ }]), do: true
   defp compile?(Mix.Dep[status: { :noappfile, _ }]), do: true
   defp compile?(Mix.Dep[status: :compile]), do: true
   defp compile?(_), do: false

lib/mix/test/mix/tasks/deps_test.exs

@@ -504,14 +504,11 @@ defmodule Mix.Tasks.DepsTest do
       File.write!("_build/dev/lib/ok/.compile.lock", "the_future")
       Mix.Task.clear
 
-      assert_raise Mix.Error, "Can't continue due to errors on dependencies", fn ->
-        Mix.Tasks.Deps.Check.run []
-      end
-
-      assert_received { :mix_shell, :error, ["* ok (deps/ok)"] }
-      assert_received { :mix_shell, :error, ["  the dependency is built with an out-of-date elixir version, run `mix deps.get`"] }
+      Mix.Tasks.Deps.run []
+      assert_received { :mix_shell, :info, ["* ok (deps/ok)"] }
+      assert_received { :mix_shell, :info, ["  the dependency is built with an out-of-date elixir version, run `mix deps.compile`"] }
 
-      Mix.Tasks.Deps.Get.run []
+      Mix.Tasks.Deps.Check.run []
       assert_received { :mix_shell, :info, ["* Compiling ok"] }
     end
   end