feat: Python 3.12 loop_factory

Author: Chaoses-Ib

README.md

@@ -41,3 +41,10 @@ An event loop can be patched whether it is already running
 or not. Only event loops from asyncio can be patched;
 Loops from other projects, such as uvloop or quamash,
 generally can't be patched.
+
+## Comparison with `nest_asyncio`
+`nest-asyncio2` is a fork of the unmaintained [`nest_asyncio`](https://github.com/erdewit/nest_asyncio), with the following changes:
+- Python 3.12 `loop_factory` parameter support
+- Python 3.14 support (`asyncio.current_task()` and others are broken in `nest_asyncio`)
+
+All interfaces are kept as they are. To migrate, you just need to change the package and module name to `nest_asyncio2`.

nest_asyncio2.py

@@ -18,10 +18,7 @@ def apply(loop=None):
     loop = loop or asyncio.get_event_loop()
     _patch_loop(loop)
 
-
-def _patch_asyncio():
-    """Patch asyncio module to use pure Python tasks and futures."""
-
+if sys.version_info < (3, 12, 0):    
     def run(main, *, debug=False):
         loop = asyncio.get_event_loop()
         loop.set_debug(debug)
@@ -33,6 +30,35 @@ def run(main, *, debug=False):
                 task.cancel()
                 with suppress(asyncio.CancelledError):
                     loop.run_until_complete(task)
+else:
+    def run(main, *, debug=False, loop_factory=None):
+        try:
+            loop = asyncio.get_running_loop()
+        except RuntimeError:
+            if loop_factory is None:
+                loop_factory = asyncio.new_event_loop
+            # if sys.version_info < (3, 16, 0):
+            #     policy = asyncio.events._get_event_loop_policy()
+            #     try:
+            #         loop = policy.get_event_loop()
+            #     except RuntimeError:
+            #         loop = loop_factory()
+            # else:
+            #     loop = loop_factory()
+            loop = loop_factory()
+
+        loop.set_debug(debug)
+        task = asyncio.ensure_future(main, loop=loop)
+        try:
+            return loop.run_until_complete(task)
+        finally:
+            if not task.done():
+                task.cancel()
+                with suppress(asyncio.CancelledError):
+                    loop.run_until_complete(task)
+
+def _patch_asyncio():
+    """Patch asyncio module to use pure Python tasks and futures."""
 
     def _get_event_loop(stacklevel=3):
         loop = events._get_running_loop()

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = nest-asyncio2
-version = 1.6.0
+version = 1.6.1
 author = Ewald R. de Wit
 author_email = [email protected]
 license = BSD
@@ -22,6 +22,8 @@ classifiers =
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11
     Programming Language :: Python :: 3.12
+    Programming Language :: Python :: 3.13
+    Programming Language :: Python :: 3.14
     Programming Language :: Python :: 3 :: Only
     Framework :: AsyncIO
 

tests/312_loop_factory.py

@@ -0,0 +1,37 @@
+# /// script
+# requires-python = ">=3.12"
+# dependencies = [
+#     "nest-asyncio2",
+# ]
+#
+# [tool.uv.sources]
+# nest-asyncio2 = { path = "../", editable = true }
+# ///
+import asyncio
+import nest_asyncio2
+
+nest_asyncio2.apply()
+
+async def f():
+    print(asyncio.get_running_loop())
+    assert asyncio.get_running_loop() is not None
+
+    print(asyncio.tasks._current_tasks)
+    # assert asyncio.tasks._current_tasks == {}
+
+    print(asyncio.tasks.current_task())
+    assert asyncio.tasks.current_task() is not None
+
+    print(asyncio.tasks._py_current_task())
+    # assert asyncio.tasks._py_current_task() is None
+
+    print(asyncio.tasks._current_tasks)
+    # assert asyncio.tasks._current_tasks == {}
+
+hit = False
+def loop_factory():
+    global hit
+    hit = True
+    return asyncio.new_event_loop()
+asyncio.run(f(), loop_factory=loop_factory)
+assert hit

tests/test.ps1

@@ -30,6 +30,15 @@ if (!$?) {
     throw "3.14"
 }
 
+uv run --python 3.12 312_loop_factory.py
+if (!$?) {
+    throw "312_loop_factory"
+}
+uv run --python 3.14 312_loop_factory.py
+if (!$?) {
+    throw "314_loop_factory"
+}
+
 uv run --python 3.14 314_task.py
 if (!$?) {
     throw "314_task"