From c0522c1bd97d2db38ea794931f3e127f70fa04d2 Mon Sep 17 00:00:00 2001
From: NIC619 <twedusuck@gmail.com>
Date: Sun, 17 Nov 2019 21:52:05 +0800
Subject: [PATCH] Check if entry exists in dictionary before delete

---
 libp2p/pubsub/mcache.py                   | 3 ++-
 libp2p/stream_muxer/mplex/mplex.py        | 6 ++++--
 libp2p/stream_muxer/mplex/mplex_stream.py | 3 ++-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/libp2p/pubsub/mcache.py b/libp2p/pubsub/mcache.py
index 233b7cf..b17f867 100644
--- a/libp2p/pubsub/mcache.py
+++ b/libp2p/pubsub/mcache.py
@@ -96,7 +96,8 @@ class MessageCache:
         last_entries: List[CacheEntry] = self.history[len(self.history) - 1]
 
         for entry in last_entries:
-            del self.msgs[entry.mid]
+            if entry.mid in self.msgs:
+                del self.msgs[entry.mid]
 
         i: int = len(self.history) - 2
 
diff --git a/libp2p/stream_muxer/mplex/mplex.py b/libp2p/stream_muxer/mplex/mplex.py
index 2228360..1a43c7c 100644
--- a/libp2p/stream_muxer/mplex/mplex.py
+++ b/libp2p/stream_muxer/mplex/mplex.py
@@ -297,7 +297,8 @@ class Mplex(IMuxedConn):
         #   the entry of this stream, to avoid others from accessing it.
         if is_local_closed:
             async with self.streams_lock:
-                del self.streams[stream_id]
+                if stream_id in self.streams:
+                    del self.streams[stream_id]
 
     async def _handle_reset(self, stream_id: StreamID) -> None:
         async with self.streams_lock:
@@ -315,7 +316,8 @@ class Mplex(IMuxedConn):
             if not stream.event_local_closed.is_set():
                 stream.event_local_closed.set()
         async with self.streams_lock:
-            del self.streams[stream_id]
+            if stream_id in self.streams:
+                del self.streams[stream_id]
 
     async def _cleanup(self) -> None:
         if not self.event_shutting_down.is_set():
diff --git a/libp2p/stream_muxer/mplex/mplex_stream.py b/libp2p/stream_muxer/mplex/mplex_stream.py
index 3f283c8..f080d3c 100644
--- a/libp2p/stream_muxer/mplex/mplex_stream.py
+++ b/libp2p/stream_muxer/mplex/mplex_stream.py
@@ -180,7 +180,8 @@ class MplexStream(IMuxedStream):
         if _is_remote_closed:
             # Both sides are closed, we can safely remove the buffer from the dict.
             async with self.muxed_conn.streams_lock:
-                del self.muxed_conn.streams[self.stream_id]
+                if self.stream_id in self.muxed_conn.streams:
+                    del self.muxed_conn.streams[self.stream_id]
 
     async def reset(self) -> None:
         """closes both ends of the stream tells this remote side to hang up."""