Translate built-in Elixir apps sources, closes #6562

Author: José Valim

lib/iex/lib/iex/introspection.ex

@@ -114,7 +114,8 @@ defmodule IEx.Introspection do
   defp open_mfa(module, fun, arity) do
     with {:module, _} <- Code.ensure_loaded(module),
          source when is_list(source) <- module.module_info(:compile)[:source] do
-      open_abstract_code(module, fun, arity, List.to_string(source))
+      source = rewrite_elixir_source(module, source)
+      open_abstract_code(module, fun, arity, source)
     else
       _ -> :error
     end
@@ -158,6 +159,21 @@ defmodule IEx.Introspection do
     end
   end
 
+  defp rewrite_elixir_source(module, source) do
+    case :application.get_application(module) do
+      {:ok, app} when app in [:eex, :elixir, :ex_unit, :iex, :logger, :mix] ->
+        {in_app, [lib_or_src | _]} =
+          source
+          |> Path.split()
+          |> Enum.reverse()
+          |> Enum.split_while(& &1 not in ["lib", "src"])
+
+        Application.app_dir(app, Path.join([lib_or_src | Enum.reverse(in_app)]))
+      _ ->
+        List.to_string(source)
+    end
+  end
+
   @doc """
   Prints documentation.
   """

lib/iex/test/iex/helpers_test.exs

@@ -123,8 +123,8 @@ defmodule IEx.HelpersTest do
   end
 
   describe "open" do
-    @iex_helpers Path.expand("../../lib/iex/helpers.ex", __DIR__)
-    @elixir_erl Path.expand("../../../elixir/src/elixir.erl", __DIR__)
+    @iex_helpers "iex/lib/iex/helpers.ex"
+    @elixir_erl "elixir/src/elixir.erl"
     @editor System.get_env("ELIXIR_EDITOR")
 
     test "opens __FILE__ and __LINE__" do
@@ -137,48 +137,48 @@ defmodule IEx.HelpersTest do
 
     test "opens Elixir module" do
       assert capture_iex("open(IEx.Helpers)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:1/
+             ~r/#{@iex_helpers}:1$/
     end
 
     test "opens function" do
       assert capture_iex("open(h)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
     end
 
     test "opens function/arity" do
       assert capture_iex("open(b/1)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
       assert capture_iex("open(h/0)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
     end
 
     test "opens module.function" do
       assert capture_iex("open(IEx.Helpers.b)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
       assert capture_iex("open(IEx.Helpers.h)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
     end
 
     test "opens module.function/arity" do
       assert capture_iex("open(IEx.Helpers.b/1)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
       assert capture_iex("open(IEx.Helpers.h/0)") |> maybe_trim_quotes() =~
-             ~r/#{@iex_helpers}:\d+/
+             ~r/#{@iex_helpers}:\d+$/
     end
 
     test "opens Erlang module" do
       assert capture_iex("open(:elixir)") |> maybe_trim_quotes() =~
-             ~r/#{@elixir_erl}:\d+/
+             ~r/#{@elixir_erl}:\d+$/
     end
 
     test "opens Erlang module.function" do
       assert capture_iex("open(:elixir.start)") |> maybe_trim_quotes() =~
-             ~r/#{@elixir_erl}:\d+/
+             ~r/#{@elixir_erl}:\d+$/
     end
 
     test "opens Erlang module.function/arity" do
       assert capture_iex("open(:elixir.start/2)") |> maybe_trim_quotes() =~
-             ~r/#{@elixir_erl}:\d+/
+             ~r/#{@elixir_erl}:\d+$/
     end
 
     test "errors if module is not available" do