From a96f142d2a32bb0ce2317dc40de8d2cbb9e64873 Mon Sep 17 00:00:00 2001
From: Bastien Gerard <bast.gerard@gmail.com>
Date: Mon, 4 Mar 2024 14:35:12 +0100
Subject: [PATCH 1/3] Fix bug in mutable thread local related with
 no_dereference ctx manager added in 0.28.0

---
 mongoengine/context_managers.py |  8 ++++--
 tests/test_context_managers.py  | 44 ++++++++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/mongoengine/context_managers.py b/mongoengine/context_managers.py
index a4c90d476..f16753eea 100644
--- a/mongoengine/context_managers.py
+++ b/mongoengine/context_managers.py
@@ -20,8 +20,12 @@
 )
 
 
-thread_locals = threading.local()
-thread_locals.no_dereferencing_class = {}
+class MyThreadLocals(threading.local):
+    def __init__(self):
+        self.no_dereferencing_class = {}
+
+
+thread_locals = MyThreadLocals()
 
 
 def no_dereferencing_active_for_class(cls):
diff --git a/tests/test_context_managers.py b/tests/test_context_managers.py
index ac9ded729..6d1b76120 100644
--- a/tests/test_context_managers.py
+++ b/tests/test_context_managers.py
@@ -1,4 +1,7 @@
+import random
+import time
 import unittest
+from threading import Thread
 
 import pytest
 from bson import DBRef
@@ -18,6 +21,31 @@
 from tests.utils import MongoDBTestCase
 
 
+class TestableThread(Thread):
+    """
+    Wrapper around `threading.Thread` that propagates exceptions.
+
+    REF: https://gist.github.com/sbrugman/59b3535ebcd5aa0e2598293cfa58b6ab
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.exc = None
+
+    def run(self):
+        try:
+            super().run()
+        except BaseException as e:
+            self.exc = e
+        # finally:
+        #     del self._target, self._args, self._kwargs
+
+    def join(self, timeout=None):
+        super().join(timeout)
+        if self.exc:
+            raise self.exc
+
+
 class TestContextManagers(MongoDBTestCase):
     def test_set_write_concern(self):
         class User(Document):
@@ -172,13 +200,27 @@ class Group(Document):
                 group = Group.objects.first()
                 assert isinstance(group.ref, DBRef)
 
-            # make sure its still off here
+            # make sure it's still off here
             group = Group.objects.first()
             assert isinstance(group.ref, DBRef)
 
         group = Group.objects.first()
         assert isinstance(group.ref, User)
 
+        def run_in_thread(id):
+            time.sleep(random.uniform(0.1, 0.5))  # Force desync of threads
+            if id % 2 == 0:
+                with no_dereference(Group):
+                    group = Group.objects.first()
+                    assert isinstance(group.ref, DBRef)
+            else:
+                group = Group.objects.first()
+                assert isinstance(group.ref, User)
+
+        threads = [TestableThread(target=run_in_thread, args=(id,)) for id in range(10)]
+        _ = [th.start() for th in threads]
+        _ = [th.join() for th in threads]
+
     def test_no_dereference_context_manager_dbref(self):
         """Ensure that DBRef items in ListFields aren't dereferenced"""
 

From b12372375f034efb88bbc315db4cfd94feeac48f Mon Sep 17 00:00:00 2001
From: Bastien Gerard <bast.gerard@gmail.com>
Date: Mon, 4 Mar 2024 14:38:08 +0100
Subject: [PATCH 2/3] bump version and update changelog for 0.28.1

---
 docs/changelog.rst      | 4 ++++
 mongoengine/__init__.py | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 0c767b576..81e1cf59e 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -8,6 +8,10 @@ Development
 ===========
 - (Fill this out as you fix issues and develop your features).
 
+Changes in 0.28.1
+=================
+- Fix bug related with recent updates to no_dereference context manager #2799
+
 Changes in 0.28.0
 =================
 - Fix for uuidRepresentation not read when provided in URI #2741
diff --git a/mongoengine/__init__.py b/mongoengine/__init__.py
index e0bf7d76d..334ad0d08 100644
--- a/mongoengine/__init__.py
+++ b/mongoengine/__init__.py
@@ -29,7 +29,7 @@
 )
 
 
-VERSION = (0, 28, 0)
+VERSION = (0, 28, 1)
 
 
 def get_version():

From 7b230270b1d568363a0797c0f81c4075cc3280c6 Mon Sep 17 00:00:00 2001
From: Bastien Gerard <bast.gerard@gmail.com>
Date: Mon, 4 Mar 2024 19:08:23 +0100
Subject: [PATCH 3/3] remove commented code

---
 tests/test_context_managers.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tests/test_context_managers.py b/tests/test_context_managers.py
index 6d1b76120..69c8931dd 100644
--- a/tests/test_context_managers.py
+++ b/tests/test_context_managers.py
@@ -37,8 +37,6 @@ def run(self):
             super().run()
         except BaseException as e:
             self.exc = e
-        # finally:
-        #     del self._target, self._args, self._kwargs
 
     def join(self, timeout=None):
         super().join(timeout)