Method presort_deletes

lib/sqlalchemy/orm/dependency.py:742–764

(self, uowcommit, states)

                uow.dependencies.update([(delete_parent, child_action)])

    def presort_deletes(self, uowcommit, states):
        if self.cascade.delete or self.cascade.delete_orphan:
            for state in states:
                history = uowcommit.get_attribute_history(
                    state, self.key, self._passive_delete_flag
                )
                if history:
                    if self.cascade.delete_orphan:
                        todelete = history.sum()
                    else:
                        todelete = history.non_deleted()
                    for child in todelete:
                        if child is None:
                            continue
                        uowcommit.register_object(
                            child,
                            isdelete=True,
                            operation="delete",
                            prop=self.prop,
                        )
                        t = self.mapper.cascade_iterator("delete", child)
                        for c, m, st_, dct_ in t:
                            uowcommit.register_object(st_, isdelete=True)

    def presort_saves(self, uowcommit, states):
        for state in states: