Fix race condition on connect when tracing is active (aio-libs#5259)

bobh66 · Nov 24, 2020 · 1be1dfb · 1be1dfb
1 parent 6f73339
commit 1be1dfb
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diff --git a/CHANGES/5259.bugfix b/CHANGES/5259.bugfix
@@ -0,0 +1 @@
+Acquire the connection before running traces to prevent race condition.
diff --git a/aiohttp/connector.py b/aiohttp/connector.py
@@ -525,8 +525,14 @@ async def connect(
                     await trace.send_connection_create_end()
         else:
             if traces:
+                # Acquire the connection to prevent race conditions while hendling traces
+                placeholder = cast(ResponseHandler, _TransportPlaceholder(self._loop))
+                self._acquired.add(placeholder)
+                self._acquired_per_host[key].add(placeholder)
                 for trace in traces:
                     await trace.send_connection_reuseconn()
+                self._acquired.remove(placeholder)
+                self._drop_acquired_per_host(key, placeholder)
 
         self._acquired.add(proto)
         self._acquired_per_host[key].add(proto)