Use get_running_loop instead of get_event_loop

pydantic_ai_slim/pydantic_ai/agent.py

@@ -13,7 +13,7 @@
 from typing_extensions import TypeGuard, TypeVar, deprecated
 
 from pydantic_graph import End, Graph, GraphRun, GraphRunContext
-from pydantic_graph._utils import get_event_loop
+from pydantic_graph._utils import run_until_complete
 
 from . import (
     _agent_graph,
@@ -567,7 +567,7 @@ def run_sync(
         """
         if infer_name and self.name is None:
             self._infer_name(inspect.currentframe())
-        return get_event_loop().run_until_complete(
+        return run_until_complete(
             self.run(
                 user_prompt,
                 result_type=result_type,

pydantic_graph/pydantic_graph/_utils.py

@@ -1,7 +1,9 @@
 from __future__ import annotations as _annotations
 
 import asyncio
+import sys
 import types
+from collections.abc import Coroutine
 from functools import partial
 from typing import Any, Callable, TypeVar
 
@@ -10,15 +12,6 @@
 from typing_inspection.introspection import is_union_origin
 
 
-def get_event_loop():
-    try:
-        event_loop = asyncio.get_event_loop()
-    except RuntimeError:
-        event_loop = asyncio.new_event_loop()
-        asyncio.set_event_loop(event_loop)
-    return event_loop
-
-
 def get_union_args(tp: Any) -> tuple[Any, ...]:
     """Extract the arguments of a Union type if `response_type` is a union, otherwise return an empty tuple."""
     # similar to `pydantic_ai_slim/pydantic_ai/_result.py:get_union_args`
@@ -100,3 +93,15 @@ async def run_in_executor(func: Callable[_P, _R], *args: _P.args, **kwargs: _P.k
         return await asyncio.get_running_loop().run_in_executor(None, partial(func, *args, **kwargs))
     else:
         return await asyncio.get_running_loop().run_in_executor(None, func, *args)  # type: ignore
+
+
+def run_until_complete(coro: Coroutine[None, None, _R]) -> _R:
+    if sys.version_info < (3, 11):
+        try:
+            loop = asyncio.new_event_loop()
+            return loop.run_until_complete(coro)
+        finally:
+            loop.close()
+    else:
+        with asyncio.runners.Runner(loop_factory=asyncio.new_event_loop) as runner:
+            return runner.run(coro)

pydantic_graph/pydantic_graph/graph.py

@@ -202,7 +202,7 @@ def run_sync(
         if infer_name and self.name is None:
             self._infer_name(inspect.currentframe())
 
-        return _utils.get_event_loop().run_until_complete(
+        return _utils.run_until_complete(
             self.run(start_node, state=state, deps=deps, persistence=persistence, infer_name=False)
         )
 

tests/graph/test_utils.py

@@ -1,12 +1,19 @@
 from threading import Thread
 
-from pydantic_graph._utils import get_event_loop
+from pydantic_graph._utils import run_until_complete
 
 
-def test_get_event_loop_in_thread():
+def test_run_until_complete_in_main_thread():
+    async def run(): ...
+
+    run_until_complete(run())
+
+
+def test_run_until_complete_in_thread():
+    async def run(): ...
+
     def get_and_close_event_loop():
-        event_loop = get_event_loop()
-        event_loop.close()
+        run_until_complete(run())
 
     thread = Thread(target=get_and_close_event_loop)
     thread.start()