as seen in https://bugs.launchpad.net/oslo.db/+bug/1814182, oslo_db Query.soft_delete will by design generate lots of warnings like:
sqlalchemy.exc.SAWarning: Evaluating non-mapped column expression 'updated_at' onto ORM instances; this is a deprecated use case. Please make use of the actual mapped columns in ORM-evaluated UPDATE / DELETE expressions.
this is because the "evaluate" synchronization strategy would like to search for objects and update them based on the UPDATE criteria passed, however the columns given, literal_column('id'), literal_column('updated_at'), are not mapped to anything. the evaluator has to make a guess that the string contained in these expressions should be matched to a mapped attribute on the given entity and this guess was first removed in https://docs.sqlalchemy.org/en/latest/changelog/changelog_12.html#change-b1e620dece39006ab44c47044e9a6fee, then added back in https://docs.sqlalchemy.org/en/latest/changelog/changelog_12.html#change-dff3a469788c81a46440584406cb22be with a warning (likely since oslo.db is invoking it)
the correct implementation should be:
class Query(sqlalchemy.orm.query.Query):
"""Subclass of sqlalchemy.query with soft_delete() method."""
def soft_delete(self, synchronize_session='evaluate'):
entity = self.column_descriptions[0]['entity']
return self.update({'deleted': entity.id,
'updated_at': entity.updated_at,
'deleted_at': timeutils.utcnow()},
synchronize_session=synchronize_session)
Thanks Mike, I can confirm that your patch fixes the warning when I patched it into my nova py35 tox environment and re-ran tests where I have the SAWarning setup with a warnings filter to be treated as an error and the test, which was failing before, is passing now.