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"""test the current state of the hasparent() flag."""
from sqlalchemy.testing import assert_raises, assert_raises_message
from sqlalchemy import Integer, String, ForeignKey, Sequence, \
exc as sa_exc
from sqlalchemy.testing.schema import Table, Column
from sqlalchemy.orm import mapper, relationship, create_session, \
sessionmaker, class_mapper, backref, Session
from sqlalchemy.orm import attributes, exc as orm_exc
from sqlalchemy import testing
from sqlalchemy.testing import eq_
from sqlalchemy.testing import fixtures
from test.orm import _fixtures
from sqlalchemy.testing.util import gc_collect
class ParentRemovalTest(fixtures.MappedTest):
"""Test that the 'hasparent' flag gets flipped to False
only if we're sure this object is the real parent.
In ambiguous cases a stale data exception is
raised.
"""
run_inserts = None
@classmethod
def define_tables(cls, metadata):
if testing.against('oracle'):
fk_args = dict(deferrable=True, initially='deferred')
elif testing.against('mysql'):
fk_args = {}
else:
fk_args = dict(onupdate='cascade')
Table('users', metadata,
Column('id', Integer, primary_key=True, test_needs_autoincrement=True),
)
Table('addresses', metadata,
Column('id', Integer, primary_key=True, test_needs_autoincrement=True),
Column('user_id', Integer, ForeignKey('users.id', **fk_args)),
)
@classmethod
def setup_classes(cls):
class User(cls.Comparable):
pass
class Address(cls.Comparable):
pass
@classmethod
def setup_mappers(cls):
mapper(cls.classes.Address, cls.tables.addresses)
mapper(cls.classes.User, cls.tables.users, properties={
'addresses':relationship(cls.classes.Address,
cascade='all, delete-orphan'),
})
def _assert_hasparent(self, a1):
assert attributes.has_parent(
self.classes.User, a1, "addresses")
def _assert_not_hasparent(self, a1):
assert not attributes.has_parent(
self.classes.User, a1, "addresses")
def _fixture(self):
User, Address = self.classes.User, self.classes.Address
s = Session()
u1 = User()
a1 = Address()
u1.addresses.append(a1)
s.add(u1)
s.flush()
return s, u1, a1
def test_stale_state_positive(self):
User = self.classes.User
s, u1, a1 = self._fixture()
s.expunge(u1)
u1 = s.query(User).first()
u1.addresses.remove(a1)
self._assert_not_hasparent(a1)
@testing.requires.predictable_gc
def test_stale_state_positive_gc(self):
User = self.classes.User
s, u1, a1 = self._fixture()
s.expunge(u1)
del u1
gc_collect()
u1 = s.query(User).first()
u1.addresses.remove(a1)
self._assert_not_hasparent(a1)
@testing.requires.predictable_gc
def test_stale_state_positive_pk_change(self):
"""Illustrate that we can't easily link a
stale state to a fresh one if the fresh one has
a PK change (unless we a. tracked all the previous PKs,
wasteful, or b. recycled states - time consuming,
breaks lots of edge cases, destabilizes the code)
"""
User = self.classes.User
s, u1, a1 = self._fixture()
s._expunge_states([attributes.instance_state(u1)])
del u1
gc_collect()
u1 = s.query(User).first()
# primary key change. now we
# can't rely on state.key as the
# identifier.
u1.id = 5
a1.user_id = 5
s.flush()
assert_raises_message(
orm_exc.StaleDataError,
"can't be sure this is the most recent parent.",
u1.addresses.remove, a1
)
# unfortunately, u1.addresses was impacted
# here
assert u1.addresses == []
# expire all and we can continue
s.expire_all()
u1.addresses.remove(a1)
self._assert_not_hasparent(a1)
def test_stale_state_negative_child_expired(self):
"""illustrate the current behavior of
expiration on the child.
there's some uncertainty here in how
this use case should work.
"""
User = self.classes.User
s, u1, a1 = self._fixture()
u2 = User(addresses=[a1])
s.expire(a1)
u1.addresses.remove(a1)
# controversy here. The action is
# to expire one object, not the other, and remove;
# this is pretty abusive in any case. for now
# we are expiring away the 'parents' collection
# so the remove will unset the hasparent flag.
# this is what has occurred historically in any case.
self._assert_not_hasparent(a1)
#self._assert_hasparent(a1)
@testing.requires.predictable_gc
def test_stale_state_negative(self):
User = self.classes.User
s, u1, a1 = self._fixture()
u2 = User(addresses=[a1])
s.add(u2)
s.flush()
s._expunge_states([attributes.instance_state(u2)])
del u2
gc_collect()
assert_raises_message(
orm_exc.StaleDataError,
"can't be sure this is the most recent parent.",
u1.addresses.remove, a1
)
s.flush()
self._assert_hasparent(a1)
def test_fresh_state_positive(self):
User = self.classes.User
s, u1, a1 = self._fixture()
self._assert_hasparent(a1)
def test_fresh_state_negative(self):
User = self.classes.User
s, u1, a1 = self._fixture()
u1.addresses.remove(a1)
self._assert_not_hasparent(a1)
|
