Method merge

lib/sqlalchemy/orm/properties.py:338–362

(
        self,
        session: Session,
        source_state: InstanceState[Any],
        source_dict: _InstanceDict,
        dest_state: InstanceState[Any],
        dest_dict: _InstanceDict,
        load: bool,
        _recursive: Dict[Any, object],
        _resolve_conflict_map: Dict[_IdentityKeyType[Any], object],
    )

        )

    def merge(
        self,
        session: Session,
        source_state: InstanceState[Any],
        source_dict: _InstanceDict,
        dest_state: InstanceState[Any],
        dest_dict: _InstanceDict,
        load: bool,
        _recursive: Dict[Any, object],
        _resolve_conflict_map: Dict[_IdentityKeyType[Any], object],
    ) -> None:
        if not self.instrument:
            return
        elif self.key in source_dict:
            value = source_dict[self.key]

            if not load:
                dest_dict[self.key] = value
            else:
                impl = dest_state.get_impl(self.key)
                impl.set(dest_state, dest_dict, value, None)
        elif dest_state.has_identity and self.key not in dest_dict:
            dest_state._expire_attributes(
                dest_dict, [self.key], no_loader=True
            )

    class Comparator(util.MemoizedSlots, PropComparator[_PT]):
        """Produce boolean, comparison, and other operators for