From cb89061627c15f4d2ee52712433efb3a5fdbb2d4 Mon Sep 17 00:00:00 2001
From: Noah Stapp <noah.stapp@mongodb.com>
Date: Fri, 26 Jul 2024 09:49:28 -0700
Subject: [PATCH] PYTHON-4537 - Use selector asyncio loop on windows tests
 (#1748)

---
 pymongo/asynchronous/periodic_executor.py | 12 +++++++++++-
 pymongo/synchronous/periodic_executor.py  | 12 +++++++++++-
 test/__init__.py                          | 10 ++++++++++
 test/asynchronous/__init__.py             | 10 ++++++++++
 4 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/pymongo/asynchronous/periodic_executor.py b/pymongo/asynchronous/periodic_executor.py
index 337d10f13..f3d2fddba 100644
--- a/pymongo/asynchronous/periodic_executor.py
+++ b/pymongo/asynchronous/periodic_executor.py
@@ -65,7 +65,17 @@ class PeriodicExecutor:
         return f"<{self.__class__.__name__}(name={self._name}) object at 0x{id(self):x}>"
 
     def _run_async(self) -> None:
-        asyncio.run(self._run())  # type: ignore[func-returns-value]
+        # The default asyncio loop implementation on Windows
+        # has issues with sharing sockets across loops (https://github.com/python/cpython/issues/122240)
+        # We explicitly use a different loop implementation here to prevent that issue
+        if sys.platform == "win32":
+            loop = asyncio.SelectorEventLoop()
+            try:
+                loop.run_until_complete(self._run())  # type: ignore[func-returns-value]
+            finally:
+                loop.close()
+        else:
+            asyncio.run(self._run())  # type: ignore[func-returns-value]
 
     def open(self) -> None:
         """Start. Multiple calls have no effect.
diff --git a/pymongo/synchronous/periodic_executor.py b/pymongo/synchronous/periodic_executor.py
index 43125016b..525268b14 100644
--- a/pymongo/synchronous/periodic_executor.py
+++ b/pymongo/synchronous/periodic_executor.py
@@ -65,7 +65,17 @@ class PeriodicExecutor:
         return f"<{self.__class__.__name__}(name={self._name}) object at 0x{id(self):x}>"
 
     def _run_async(self) -> None:
-        asyncio.run(self._run())  # type: ignore[func-returns-value]
+        # The default asyncio loop implementation on Windows
+        # has issues with sharing sockets across loops (https://github.com/python/cpython/issues/122240)
+        # We explicitly use a different loop implementation here to prevent that issue
+        if sys.platform == "win32":
+            loop = asyncio.SelectorEventLoop()
+            try:
+                loop.run_until_complete(self._run())  # type: ignore[func-returns-value]
+            finally:
+                loop.close()
+        else:
+            asyncio.run(self._run())  # type: ignore[func-returns-value]
 
     def open(self) -> None:
         """Start. Multiple calls have no effect.
diff --git a/test/__init__.py b/test/__init__.py
index b8bd18511..b603ae0a5 100644
--- a/test/__init__.py
+++ b/test/__init__.py
@@ -79,6 +79,16 @@ from pymongo.synchronous.mongo_client import MongoClient
 
 _IS_SYNC = True
 
+# The default asyncio loop implementation on Windows
+# has issues with sharing sockets across loops (https://github.com/python/cpython/issues/122240)
+# We explicitly use a different loop implementation here to prevent that issue
+if (
+    not _IS_SYNC
+    and sys.platform == "win32"
+    and asyncio.get_event_loop_policy() == asyncio.WindowsProactorEventLoopPolicy
+):
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())  # type: ignore[attr-defined]
+
 
 class ClientContext:
     client: MongoClient
diff --git a/test/asynchronous/__init__.py b/test/asynchronous/__init__.py
index 6f0785c4f..878ef81ba 100644
--- a/test/asynchronous/__init__.py
+++ b/test/asynchronous/__init__.py
@@ -79,6 +79,16 @@ from pymongo.ssl_support import HAVE_SSL, _ssl  # type:ignore[attr-defined]
 
 _IS_SYNC = False
 
+# The default asyncio loop implementation on Windows
+# has issues with sharing sockets across loops (https://github.com/python/cpython/issues/122240)
+# We explicitly use a different loop implementation here to prevent that issue
+if (
+    not _IS_SYNC
+    and sys.platform == "win32"
+    and asyncio.get_event_loop_policy() == asyncio.WindowsProactorEventLoopPolicy
+):
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())  # type: ignore[attr-defined]
+
 
 class AsyncClientContext:
     client: AsyncMongoClient