Validate application properties before altering them

Closes #4873.

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: lexmag

lib/elixir/test/elixir/kernel/warning_test.exs

@@ -421,8 +421,8 @@ defmodule Kernel.WarningTest do
     assert capture_err(fn ->
       Code.eval_string ~S"""
       defmodule Sample do
-      def hello(arg \\ 0), do: nil
-      def hello(arg), do: nil
+        def hello(arg \\ 0), do: nil
+        def hello(arg), do: nil
       end
       """
     end) =~ "definitions with multiple clauses and default values require a function head"
@@ -551,7 +551,7 @@ defmodule Kernel.WarningTest do
       """
     end) =~ "undefined behaviour function foo/0 (for behaviour Sample1)"
   after
-    purge [Sample1, Sample2, Sample3]
+    purge [Sample1, Sample2]
   end
 
   test "undefined macro for behaviour" do
@@ -567,7 +567,7 @@ defmodule Kernel.WarningTest do
       """
     end) =~ "undefined behaviour macro foo/0 (for behaviour Sample1)"
   after
-    purge [Sample1, Sample2, Sample3]
+    purge [Sample1, Sample2]
   end
 
   test "undefined behavior" do

lib/mix/lib/mix/tasks/compile.app.ex

@@ -90,14 +90,14 @@ defmodule Mix.Tasks.Compile.App do
         best_guess
       end
 
+      properties = ensure_correct_properties(app, config, properties)
+
       # Ensure we always prepend the standard application dependencies
-      core_apps = [:kernel, :stdlib] ++ language_app(config)
       properties = Keyword.update!(properties, :applications, fn apps ->
-        core_apps ++ apps
+        [:kernel, :stdlib] ++ language_app(config) ++ apps
       end)
 
-      properties = ensure_correct_properties(app, config, properties)
-      contents   = {:application, app, properties}
+      contents = {:application, app, properties}
 
       Mix.Project.ensure_structure()
       File.write!(target, :io_lib.format("~p.", [contents]), [:utf8])