Merge pull request #4453 from sasa1977/purge-erlang-modules-on-recompilation

purge erlang modules on recompilation

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

Author: josevalim

lib/mix/lib/mix/tasks/compile.erlang.ex

@@ -80,6 +80,12 @@ defmodule Mix.Tasks.Compile.Erlang do
 
     Mix.Compilers.Erlang.compile(manifest(), tuples, fn
       input, _output ->
+        # We're purging the module because a previous compiler (e.g. Phoenix)
+        # might have already loaded the previous version of it.
+        module = Path.basename(input, ".erl") |> String.to_atom
+        :code.purge(module)
+        :code.delete(module)
+
         file = to_erl_file(Path.rootname(input, ".erl"))
         :compile.file(file, erlc_options)
     end)

lib/mix/test/mix/tasks/compile.erlang_test.exs

@@ -59,4 +59,25 @@ defmodule Mix.Tasks.Compile.ErlangTest do
       refute File.regular?("_build/dev/lib/sample/ebin/b.beam")
     end
   end
+
+  test "compilation purges the module" do
+    in_fixture "compile_erlang", fn ->
+      # Create the first version of the module.
+      defmodule :purge_test do
+        def version, do: :v1
+      end
+      assert :v1 == :purge_test.version
+
+      # Create the second version of the module (this time as Erlang source).
+      File.write! "src/purge_test.erl", """
+      -module(purge_test).
+      -compile(export_all).
+      version() -> v2.
+      """
+      assert Mix.Tasks.Compile.Erlang.run([]) == :ok
+
+      # If the module was not purged on recompilation, this would fail.
+      assert :v2 == :purge_test.version
+    end
+  end
 end