Handle in memory modules in Xref.calls, closes #10502

Author: josevalim

lib/mix/lib/mix/tasks/xref.ex

@@ -252,7 +252,8 @@ defmodule Mix.Tasks.Xref do
          {:ok, {_, [debug_info: debug_info]}} <- :beam_lib.chunks(path, [:debug_info]),
          {:debug_info_v1, backend, data} <- debug_info,
          {:ok, %{definitions: defs}} <- backend.debug_info(:elixir_v1, module, data, []),
-         do: walk_definitions(module, source, defs)
+         do: walk_definitions(module, source, defs),
+         else: (_ -> [])
   end
 
   defp walk_definitions(module, file, definitions) do

lib/mix/test/mix/tasks/xref_test.exs

@@ -69,11 +69,29 @@ defmodule Mix.Tasks.XrefTest do
       assert_all_calls(files, output)
     end
 
-    defp assert_all_calls(files, expected) do
+    test "returns empty on cover compiled modules" do
+      files = %{
+        "lib/a.ex" => """
+        defmodule A do
+          def a, do: A.a()
+        end
+        """
+      }
+
+      assert_all_calls(files, [], fn ->
+        :cover.start()
+        :cover.compile_beam_directory(to_charlist(Mix.Project.compile_path()))
+      end)
+    after
+      :cover.stop()
+    end
+
+    defp assert_all_calls(files, expected, after_compile \\ fn -> :ok end) do
       in_fixture("no_mixfile", fn ->
         generate_files(files)
 
         Mix.Task.run("compile")
+        after_compile.()
         assert Enum.sort(Mix.Tasks.Xref.calls()) == Enum.sort(expected)
       end)
     end