equal_any() DB API helper produces incorrect SQL query

[Roman Podoliaka]

Given an attribute name and a list of values equal_any() is meant to produce a WHERE clause which returns rows for which the column (denoted by an attribute of an SQLAlchemy model) is equal to ANY of passed values that involves using of SQL OR operator. In fact, AND operator is used to combine equality expressions.

E.g. for a model:

class Instance(BaseModel):
    __tablename__ = 'instances'

   id = sa.Column('id', sa.Integer, primary_key=True)
   ...
   task_state = sa.Column('task_state', sa.String(30))

using of equal_any():

  q = model_query(context, Instance).
  constraint = Constraint({'task_state': equal_any('error', 'deleting')})
  q = constraint.apply(Instance, q)

will produce:

SELECT * from instances
WHERE task_state = 'error' AND task_state = 'deleting'

instead of expected:

SELECT * from instances
WHERE task_state = 'error' OR task_state = 'deleting'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/80431

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/80431
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8ff06df88b1f979f5a67f9d55fa0e828a6e73d04
Submitter: Jenkins
Branch: master

commit 8ff06df88b1f979f5a67f9d55fa0e828a6e73d04
Author: Roman Podoliaka <email address hidden>
Date: Thu Mar 13 23:48:56 2014 +0200

    Fix equal_any() DB API helper

    equal_any() query helper is meant to produce a WHERE clause combining
    a few conditions with OR operator in order to select the rows for
    which the given column is equal to ANY of passed values. In fact,
    it uses AND operator instead of OR, which means that an incorrect
    WHERE clause will be returned, if more than one value is passed to
    equal_any().

    This is caused by the fact that the or_() function from SQLAlchemy
    expression language is used incorrectly: it accepts unpacked
    instances of BinaryExpression, but a list of ones is passed.
    Unfortunately, in 0.7.x and 0.8.x branches of SQLAlchemy passing
    a list of values to or_() won't raise an exception immidiately,
    and the result will be an iterable, which explains why we didn't
    see equal_any() was actually broken before. Besides, equal_any() is
    rarely used in our code base and the test didn't cover the case when
    more than 1 value is passed to the function.

    This effectively fixes the error when running Nova unit tests
    with SQLAlchemy 0.9.x releases.

    Closes-Bug: #1292285

    Change-Id: If4c0f1d3e016e2affb0d49293c62ca9df0d033f7