From 853fe8a1a1c5427f9f2524155894e793858981a6 Mon Sep 17 00:00:00 2001
From: Weiliang Li <to.be.impressive@gmail.com>
Date: Wed, 10 Sep 2025 04:26:18 +0900
Subject: [PATCH] Check if main event loop is running before scheduling

Fixes #525

After some debugging, I found that `main_event_loop` is sometimes closed. If it's closed, we should not `call_soon_threadsafe`
---
 asgiref/sync.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/asgiref/sync.py b/asgiref/sync.py
index 54496efe..ffe6047f 100644
--- a/asgiref/sync.py
+++ b/asgiref/sync.py
@@ -231,7 +231,7 @@ async def new_loop_wrap() -> None:
                 finally:
                     del self.loop_thread_executors[loop]
 
-            if self.main_event_loop is not None:
+            if self.main_event_loop is not None and self.main_event_loop.is_running():
                 try:
                     self.main_event_loop.call_soon_threadsafe(
                         self.main_event_loop.create_task, awaitable