Ensure mix compiler is able to handle nested directories

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

Author: José Valim

lib/mix/lib/mix/compilers/elixir.ex

@@ -14,8 +14,9 @@ defmodule Mix.Compilers.Elixir do
   have changed at runtime.
   """
   def compile(manifest, srcs, skip, exts, dest, force, on_start) do
-    all = Mix.Utils.extract_files(srcs -- skip, exts)
-    {all_entries, skip_entries} = read_manifest(manifest, dest, skip)
+    keep = srcs -- skip
+    all  = Mix.Utils.extract_files(keep, exts)
+    {all_entries, skip_entries} = read_manifest(manifest, dest, keep)
 
     removed =
       for {_b, _m, source, _d, _f, _bin} <- all_entries, not(source in all), do: source
@@ -181,21 +182,21 @@ defmodule Mix.Compilers.Elixir do
 
   # Reads the manifest returning the results as tuples.
   # The beam files are read, removed and stored in memory.
-  defp read_manifest(manifest, dest, skip_paths) do
+  defp read_manifest(manifest, dest, keep_paths) do
     initial = {[], []}
 
     case File.read(manifest) do
       {:ok, contents} ->
-        skip_paths = Enum.map(skip_paths, &(&1 <> "/"))
+        keep_paths = Enum.map(keep_paths, &(&1 <> "/"))
         Enum.reduce String.split(contents, "\n"), initial, fn x, acc ->
-          read_manifest_entry(String.split(x, "\t"), acc, dest, skip_paths)
+          read_manifest_entry(String.split(x, "\t"), acc, dest, keep_paths)
         end
       {:error, _} ->
         initial
     end
   end
 
-  defp read_manifest_entry([_beam, module, source|deps], {keep, skip}, dest, skip_paths) do
+  defp read_manifest_entry([_beam, module, source|deps], {keep, skip}, dest, keep_paths) do
     {deps, files} =
       case Enum.split_while(deps, &(&1 != "Elixir")) do
         {deps, ["Elixir"|files]} -> {deps, files}
@@ -208,10 +209,10 @@ defmodule Mix.Compilers.Elixir do
     entry = {Path.join(dest, module <> ".beam"), module, source,
              deps, files, nil}
 
-    if String.starts_with?(source, skip_paths) do
-      {keep, [entry|skip]}
-    else
+    if String.starts_with?(source, keep_paths) do
       {[entry|keep], skip}
+    else
+      {keep, [entry|skip]}
     end
   end
 

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

@@ -172,20 +172,27 @@ defmodule Mix.Tasks.Compile.ElixirTest do
 
   defmodule SourcePathsProject do
     def project do
-      [app: :source_paths, elixirc_paths: ["web", "lib"]]
+      [app: :source_paths, elixirc_paths: ["web", "lib", "lib/foo"]]
     end
   end
 
   test "use custom source paths" do
     Mix.Project.push SourcePathsProject
 
     in_fixture "no_mixfile", fn ->
+      File.mkdir_p! "web"
+      File.write! "web/ab.ex", """
+      defmodule AB, do: :ok
+      """
+
       # Nothing to compile with the custom source paths
       assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "web"])
+      assert_received {:mix_shell, :info, ["Compiled web/ab.ex"]}
       refute_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
 
       assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "lib"])
       assert_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+      refute_received {:mix_shell, :info, ["Compiled web/ab.ex"]}
 
       # Compiling just web does not remove lib artifacts
       assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "web"])
@@ -195,4 +202,32 @@ defmodule Mix.Tasks.Compile.ElixirTest do
       refute_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
     end
   end
+
+  test "use custom source paths in subdirs" do
+    Mix.Project.push SourcePathsProject
+
+    in_fixture "no_mixfile", fn ->
+      File.mkdir_p! "lib/foo"
+      File.write! "lib/foo/ab.ex", """
+      defmodule AB, do: :ok
+      """
+
+      # Nested file (and nested file only) is compiled just once
+      assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "lib/foo"])
+      assert_received {:mix_shell, :info, ["Compiled lib/foo/ab.ex"]}
+      refute_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+      refute_received {:mix_shell, :info, ["Compiled lib/foo/ab.ex"]}
+
+      assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "lib"])
+      assert_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+      refute_received {:mix_shell, :info, ["Compiled lib/foo/ab.ex"]}
+
+      # Compiling just lib/foo does not remove lib artifacts
+      assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "lib/foo"])
+      refute_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+
+      assert Mix.Tasks.Compile.Elixir.run(["--elixirc-paths", "lib"])
+      refute_received {:mix_shell, :info, ["Compiled lib/a.ex"]}
+    end
+  end
 end