From 712d974c8ca5b5c6230d06905c885ff33793d3b1 Mon Sep 17 00:00:00 2001
From: qianduoduo0904 <qianduoduo0904@gmail.com>
Date: Tue, 23 Aug 2022 16:55:30 +0800
Subject: [PATCH] Fix hang when calling `exit()` in interpreter

---
 mars/core/entity/executable.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/mars/core/entity/executable.py b/mars/core/entity/executable.py
index e880681dce..e0064a634b 100644
--- a/mars/core/entity/executable.py
+++ b/mars/core/entity/executable.py
@@ -25,6 +25,9 @@
 from ..mode import enter_mode
 
 
+main_thread = threading.current_thread()
+
+
 class DecrefRunner:
     def __init__(self):
         self._decref_thread = None
@@ -66,11 +69,16 @@ def stop(self):
             self._queue.put_nowait((None, None, None))
             self._decref_thread.join(1)
 
-    def put(self, key: str, session_ref: ref):
+    def put(self, key: str, session_ref: ref) -> concurrent.futures.Future:
+        fut = concurrent.futures.Future()
+
+        if not main_thread.is_alive():
+            fut.set_result(None)
+            return fut
+
         if self._decref_thread is None:
             self.start()
 
-        fut = concurrent.futures.Future()
         self._queue.put_nowait((key, session_ref, fut))
         return fut