Only keep #cell: markers in stacktrace (#2351)

lib/livebook/runtime/evaluator/doctests.ex

@@ -334,7 +334,7 @@ defmodule Livebook.Runtime.Evaluator.Doctests do
   end
 
   defp format_stacktrace_entry(entry, _test_case, _test) do
-    Exception.format_stacktrace_entry(entry)
+    Livebook.Runtime.Evaluator.Formatter.format_stacktrace_entry(entry)
   end
 
   defp format_label(label), do: colorize(:cyan, "#{label}:")

lib/livebook/runtime/evaluator/formatter.ex

@@ -133,13 +133,36 @@ defmodule Livebook.Runtime.Evaluator.Formatter do
       if stacktrace == [] do
         banner
       else
-        stacktrace = Exception.format_stacktrace(stacktrace)
+        stacktrace = format_stacktrace(stacktrace)
         [banner, "\n", error_color(stacktrace)]
       end
 
     IO.iodata_to_binary(message)
   end
 
+  defp format_stacktrace(trace) do
+    case trace do
+      [] -> "\n"
+      _ -> "    " <> Enum.map_join(trace, "\n    ", &format_stacktrace_entry(&1)) <> "\n"
+    end
+  end
+
+  @doc """
+  Formats a stacktrace entry keeping only the #cell: bits.
+  """
+  def format_stacktrace_entry(entry) do
+    entry =
+      with {mod, fun, arity, info} <- entry,
+           [_ | _] = file <- info[:file],
+           [_, cell] <- :string.split(file, "#cell:") do
+        {mod, fun, arity, Keyword.put(info, :file, ~c"#cell:" ++ cell)}
+      else
+        _ -> entry
+      end
+
+    Exception.format_stacktrace_entry(entry)
+  end
+
   defp blame_match(%{match?: true, node: node}), do: Macro.to_string(node)
 
   defp blame_match(%{match?: false, node: node}) do

test/livebook/runtime/evaluator_test.exs

@@ -195,6 +195,17 @@ defmodule Livebook.Runtime.EvaluatorTest do
              """ <> _ = clean_message(message)
     end
 
+    test "only keeps #cell: markers in stacktrace", %{evaluator: evaluator} do
+      code = """
+      List.first(%{})
+      """
+
+      Evaluator.evaluate_code(evaluator, :elixir, code, :code_1, [], file: "file.ex#cell:abcDEF")
+
+      assert_receive {:runtime_evaluation_response, :code_1, error(message), metadata()}
+      assert message =~ "  #cell:abcDEF:1: (file)"
+    end
+
     test "returns additional metadata when there is a syntax error", %{evaluator: evaluator} do
       code = "1+"