Add try-except to catch ReferenceError during searching the server ob…

…ject (#1042)

* Add try-except to catch ReferenceError during searching the server object

* Update CHANGELOG.md

CHANGELOG.md

@@ -3,6 +3,10 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Fix
+
+- Catch `ReferenceError` during searching the server object , #1042.
+
 ## [0.43.2] - 2022-08-27
 
 ### Fix

streamlit_webrtc/server.py

@@ -49,7 +49,13 @@ def get_current_server():
 
         from streamlit.web.server.server import Server
 
-        servers = [obj for obj in gc.get_objects() if isinstance(obj, Server)]
+        def is_server(obj) -> bool:
+            try:
+                return isinstance(obj, Server)
+            except ReferenceError:  # This is necessary due to https://github.com/whitphx/streamlit-webrtc/issues/1040  # noqa: E501
+                return False
+
+        servers = [obj for obj in gc.get_objects() if is_server(obj)]
 
         if len(servers) == 0:
             raise RuntimeError("Unexpectedly no server exists")