Ignore tracers if lexical tracker is dead or explicitly nil

Author: josevalim

lib/elixir/src/elixir.erl

@@ -204,21 +204,23 @@ env_for_eval(Env, Opts) ->
     false -> nil
   end,
 
-  Tracers = case lists:keyfind(tracers, 1, Opts) of
+  TempTracers = case lists:keyfind(tracers, 1, Opts) of
     {tracers, TracersOpt} when is_list(TracersOpt) -> TracersOpt;
     false -> []
   end,
 
-  LexicalTracker = case lists:keyfind(lexical_tracker, 1, Opts) of
+  %% If there is a dead PID or lexical tracker is nil,
+  %% we assume the tracers also cannot be (re)used.
+  {LexicalTracker, Tracers} = case lists:keyfind(lexical_tracker, 1, Opts) of
     {lexical_tracker, Pid} when is_pid(Pid) ->
       case is_process_alive(Pid) of
-        true -> Pid;
-        false -> nil
+        true -> {Pid, TempTracers};
+        false -> {nil, []}
       end;
     {lexical_tracker, nil} ->
-      nil;
+      {nil, []};
     false ->
-      nil
+      {nil, TempTracers}
   end,
 
   FA = case lists:keyfind(function, 1, Opts) of

lib/elixir/test/elixir/code_test.exs

@@ -85,11 +85,21 @@ defmodule CodeTest do
     assert CodeTest.Sample.eval_quoted_info() == {CodeTest.Sample, "sample.ex", 13}
   end
 
-  test "eval_quoted/2 with a %Macro.Env{} struct as the second argument" do
+  test "eval_quoted/2 with %Macro.Env{} at runtime" do
     alias :lists, as: MyList
+    quoted = quote(do: MyList.flatten([[1, 2, 3]]))
 
-    assert Code.eval_quoted(quote(do: MyList.flatten([[1, 2, 3]])), [], __ENV__) ==
-             {[1, 2, 3], []}
+    assert Code.eval_quoted(quoted, [], __ENV__) == {[1, 2, 3], []}
+
+    # Let's check it discards tracers since the lexical tracker is explicitly nil
+    assert Code.eval_quoted(quoted, [], %{__ENV__ | tracers: [:bad]}) == {[1, 2, 3], []}
+  end
+
+  test "eval_quoted/2 with %Macro.Env{} at compile time" do
+    defmodule CompileTimeEnv do
+      alias String.Chars
+      {"foo", []} = Code.eval_string("Chars.to_string(:foo)", [], __ENV__)
+    end
   end
 
   test "eval_file/1" do