Open Stack

We need to decide how to handle this:

https://review.openstack.org/#/c/362991/


Basically, PyMySQL normally raises an error message like this:

(pymysql.err.IntegrityError) (1452, u'Cannot add or update a child row: 
a foreign key constraint fails (`vaceciqnzs`.`resource_entity`, 
CONSTRAINT `foo_fkey` FOREIGN KEY (`foo_id`) REFERENCES `resource_foo` 
(`id`))')

for some reason, PyMySQL 0.7.7 is now raising it like this:

(pymysql.err.IntegrityError) (1452, u'23000Cannot add or update a child 
row: a foreign key constraint fails (`vaceciqnzs`.`resource_entity`, 
CONSTRAINT `foo_fkey` FOREIGN KEY (`foo_id`) REFERENCES `resource_foo` 
(`id`))')

this impacts oslo.db's "exception re-handling" functionality which tries 
to classify this exception as a DBNonExistentConstraint exception.   It 
also breaks oslo.db's test suite locally, but in a downstream project 
would only impact its ability to intercept this exception appropriately.

now that "23000" there looks like a bug.  The above gerrit proposes to 
work around it.  However, if we didn't push out the above gerrit, we'd 
instead have to change requirements:

https://review.openstack.org/#/q/I33d5ef8f35747d3b6d3bc0bd4972ce3b7fd60371,n,z

It seems like at least one or the other would be needed for Newton.