Fix position snapshot SystemError on deepcopy

Author: cjdsellers

RELEASES.md

@@ -79,6 +79,7 @@ None
 - Fixed portfolio handling of `OrderExpired` events not updating state (margin requirements may change)
 - Fixed event handling for `ExecutionEngine` so it fully updates the `Portfolio` before to publishing execution events (#2513), thanks for reporting @stastnypremysl
 - Fixed position snapshot cache access for `ExecutionEngine`
+- Fixed position snapshot `SystemError` calling `copy.deepcopy()` by simply using a `pickle` round trip to copy the position instance
 - Fixed event purging edge cases for account and position where at least one event must be guaranteed
 - Fixed authentication for Redis when password provided with no username
 - Fixed various numpy and pandas FutureWarning(s)

nautilus_trader/cache/cache.pyx

@@ -13,7 +13,6 @@
 #  limitations under the License.
 # -------------------------------------------------------------------------------------------------
 
-import copy
 import pickle
 import time
 import uuid
@@ -2056,11 +2055,11 @@ cdef class Cache(CacheFacade):
 
         """
         cdef PositionId position_id = position.id
-        cdef list snapshots = self._position_snapshots.get(position_id)
+        cdef list[bytes] snapshots = self._position_snapshots.get(position_id)
 
-        # Reassign position ID
-        cdef Position copied_position = copy.deepcopy(position)
-        copied_position.id = PositionId(f"{position.id.to_str()}-{uuid.uuid4()}")
+        # Create snapshot with modified position ID
+        cdef Position copied_position = pickle.loads(pickle.dumps(position))
+        copied_position.id = PositionId(f"{position_id.to_str()}-{uuid.uuid4()}")
         cdef bytes position_pickled = pickle.dumps(copied_position)
 
         if snapshots is not None: