Ensure config/config.exs is really persisted

Author: José Valim

lib/elixir/lib/uri.ex

@@ -58,7 +58,7 @@ defmodule URI do
   """
   def default_port(scheme, port) when is_binary(scheme) and port > 0 do
     {:ok, dict} = Application.fetch_env(:elixir, :uri)
-    Application.put_env(:elixir, :uri, Map.put(dict, scheme, port), persist: true)
+    Application.put_env(:elixir, :uri, Map.put(dict, scheme, port), persistent: true)
   end
 
   @doc """

lib/mix/lib/mix/config.ex

@@ -21,7 +21,7 @@ defmodule Mix.Config do
   """
   def persist(config) do
     for {app, kw} <- config, {k, v} <- kw do
-      :application.set_env(app, k, v, persist: true)
+      :application.set_env(app, k, v, persistent: true)
     end
     :ok
   end

lib/mix/test/mix/tasks/loadconfig_test.exs

@@ -8,7 +8,7 @@ defmodule Mix.Tasks.LoadconfigTest do
   teardown do
     Enum.each @apps, fn app ->
       Enum.each Application.get_all_env(app), fn {key, _} ->
-        Application.delete_env(app, key, persist: true)
+        Application.delete_env(app, key, persistent: true)
       end
     end
     :ok
@@ -31,6 +31,8 @@ defmodule Mix.Tasks.LoadconfigTest do
       assert Application.fetch_env(:my_app, :key) == :error
       Mix.Tasks.Loadconfig.run []
       assert Application.fetch_env(:my_app, :key) == {:ok, :value}
+      :ok = :application.load({:application, :my_app, [vsn: '1.0.0', env: [key: :app]]})
+      assert Application.fetch_env(:my_app, :key) == {:ok, :value}
     end
   end