Make a copy of sessions to loop over

8 years ago · 0ac36aeca0
1 changed files with 4 additions and 3 deletions
--- a/server/controller.py
+++ b/server/controller.py
@ -329,8 +329,9 @@ class Controller(util.LoggedClass):
                self.cache_height = self.bp.db_height
                self.header_cache.clear()

-            for session in self.sessions:
-                if isinstance(session, ElectrumX):
+            # Make a copy; self.sessions can change whilst await-ing
+            sessions = [s for s in self.sessions if isinstance(s, ElectrumX)]
+            for session in sessions:
                await session.notify(self.bp.db_height, touched)

    def electrum_header(self, height):