python3Packages.omegaconf: improve python 3.11 support

diff --git a/omegaconf/omegaconf.py b/omegaconf/omegaconf.py

index efde14a..a2a050e 100644

--- a/omegaconf/omegaconf.py

+++ b/omegaconf/omegaconf.py

@@ -7,6 +7,7 @@ import pathlib

 import sys

 import warnings

 from collections import defaultdict

+from dataclasses import _MISSING_TYPE

 from contextlib import contextmanager

 from enum import Enum

 from textwrap import dedent

@@ -828,6 +829,8 @@ class OmegaConf:

             if obj is _DEFAULT_MARKER_:

                 obj = {}

+            if isinstance(obj, _MISSING_TYPE):

+                return OmegaConf.create({}, parent=parent, flags=flags)

             if isinstance(obj, str):

                 obj = yaml.load(obj, Loader=get_yaml_loader())

                 if obj is None:

, antlr4-python3-runtime

, buildPythonPackage

, fetchFromGitHub

, setuptools

, jre_minimal

, pydevd

, pytest-mock

buildPythonPackage rec {

  pname = "omegaconf";

  version = "2.3.0";

  format = "setuptools";

  pyproject = true;

  disabled = pythonOlder "3.6";

  src = fetchFromGitHub {

      src = ./antlr4.patch;

      antlr_jar = "${antlr4.out}/share/java/antlr-${antlr4.version}-complete.jar";

    })

    # https://github.com/omry/omegaconf/pull/1137

    ./0000-add-support-for-dataclasses_missing_type.patch

  ];

  postPatch = ''

  '';

  nativeBuildInputs = [

    setuptools

    jre_minimal

  ];