Warn on circular file imports when loading .iex.exs (#9364)

3 files changed, 24 insertions, 1 deletions

diff --git a/lib/iex/lib/iex/evaluator.ex b/lib/iex/lib/iex/evaluator.ex
index c6415fd31..ff86ed339 100644
--- a/lib/iex/lib/iex/evaluator.ex
+++ b/lib/iex/lib/iex/evaluator.ex
@@ -186,6 +186,7 @@ defmodule IEx.Evaluator do
 
       # Evaluate the contents in the same environment server_loop will run in
       env = :elixir.env_for_eval(state.env, file: path, line: 1)
+      Process.put(:iex_imported_paths, MapSet.new([path]))
       {_result, binding, env, _scope} = :elixir.eval_forms(quoted, state.binding, env)
       %{state | binding: binding, env: :elixir.env_for_eval(env, file: "iex", line: 1)}
     catch
@@ -193,6 +194,8 @@ defmodule IEx.Evaluator do
         io_result("Error while evaluating: #{path}")
         print_error(kind, error, __STACKTRACE__)
         state
+    after
+      Process.delete(:iex_imported_paths)
     end
   end
 
diff --git a/lib/iex/lib/iex/helpers.ex b/lib/iex/lib/iex/helpers.ex
index 773ea0376..9ca9c0159 100644
--- a/lib/iex/lib/iex/helpers.ex
+++ b/lib/iex/lib/iex/helpers.ex
@@ -1068,7 +1068,16 @@ defmodule IEx.Helpers do
     path = Path.expand(path)
 
     if not optional? or File.exists?(path) do
-      path |> File.read!() |> Code.string_to_quoted!(file: path)
+      if imported_paths = Process.get(:iex_imported_paths) do
+        if path in imported_paths do
+          IO.warn("path #{path} was already imported, skipping circular file imports", [])
+        else
+          Process.put(:iex_imported_paths, MapSet.put(imported_paths, path))
+          path |> File.read!() |> Code.string_to_quoted!(file: path)
+        end
+      else
+        path |> File.read!() |> Code.string_to_quoted!(file: path)
+      end
     end
   end
 
diff --git a/lib/iex/test/iex/helpers_test.exs b/lib/iex/test/iex/helpers_test.exs
index dc9821a80..d6e33638b 100644
--- a/lib/iex/test/iex/helpers_test.exs
+++ b/lib/iex/test/iex/helpers_test.exs
@@ -1000,6 +1000,17 @@ defmodule IEx.HelpersTest do
     test "does not raise if file is missing and using import_file_if_available" do
       assert "nil" == capture_iex("import_file_if_available \"nonexistent\"")
     end
+
+    test "circular imports" do
+      dot_1 = "import_file \"dot-iex-2\""
+      dot_2 = "import_file \"dot-iex-1\""
+
+      with_file(["dot-iex-1", "dot-iex-2"], [dot_1, dot_2], fn ->
+        assert capture_io(:stderr, fn ->
+                 assert capture_iex(":ok", [], dot_iex_path: "dot-iex-1") == ":ok"
+               end) =~ "dot-iex-2 was already imported, skipping circular file imports"
+      end)
+    end
   end
 
   describe "import_if_available" do