add logic for multiple pending connections

Author: blink1073

pymongo/asynchronous/pool.py

@@ -1083,6 +1083,10 @@ async def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> A
         Note that the pool does not keep a reference to the socket -- you
         must call checkin() when you're done with it.
         """
+        # Mark whether we were in ready state before starting the process, to
+        # handle the case of multiple pending connections.
+        was_ready = self.state == PoolState.READY
+
         async with self.lock:
             conn_id = self.next_connection_id
             self.next_connection_id += 1
@@ -1131,7 +1135,9 @@ async def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> A
                     reason=_verbose_connection_error_reason(ConnectionClosedReason.ERROR),
                     error=ConnectionClosedReason.ERROR,
                 )
-            if context["has_created_socket"]:
+            if context["has_created_socket"] and not (
+                was_ready and self.state == PoolState.BACKOFF
+            ):
                 await self._handle_connection_error(error, "handshake")
             if isinstance(error, (IOError, OSError, *SSLErrors)):
                 details = _get_timeout_details(self.opts)
@@ -1158,7 +1164,7 @@ async def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> A
         except BaseException as e:
             async with self.lock:
                 self.active_contexts.discard(conn.cancel_context)
-            if not has_completed_hello:
+            if not has_completed_hello and not (was_ready and self.state == PoolState.BACKOFF):
                 await self._handle_connection_error(e, "hello")
             await conn.close_conn(ConnectionClosedReason.ERROR)
             raise

pymongo/synchronous/pool.py

@@ -1081,6 +1081,10 @@ def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> Connect
         Note that the pool does not keep a reference to the socket -- you
         must call checkin() when you're done with it.
         """
+        # Mark whether we were in ready state before starting the process, to
+        # handle the case of multiple pending connections.
+        was_ready = self.state == PoolState.READY
+
         with self.lock:
             conn_id = self.next_connection_id
             self.next_connection_id += 1
@@ -1129,7 +1133,9 @@ def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> Connect
                     reason=_verbose_connection_error_reason(ConnectionClosedReason.ERROR),
                     error=ConnectionClosedReason.ERROR,
                 )
-            if context["has_created_socket"]:
+            if context["has_created_socket"] and not (
+                was_ready and self.state == PoolState.BACKOFF
+            ):
                 self._handle_connection_error(error, "handshake")
             if isinstance(error, (IOError, OSError, *SSLErrors)):
                 details = _get_timeout_details(self.opts)
@@ -1156,7 +1162,7 @@ def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> Connect
         except BaseException as e:
             with self.lock:
                 self.active_contexts.discard(conn.cancel_context)
-            if not has_completed_hello:
+            if not has_completed_hello and not (was_ready and self.state == PoolState.BACKOFF):
                 self._handle_connection_error(e, "hello")
             conn.close_conn(ConnectionClosedReason.ERROR)
             raise