sqlalchemy/test/orm/test_merge.py

from sqlalchemy.testing import assert_raises_message
import sqlalchemy as sa
from sqlalchemy import Integer, PickleType, String, ForeignKey, Text
import operator
from sqlalchemy import testing
from sqlalchemy.util import OrderedSet
from sqlalchemy.orm import mapper, relationship, create_session, \
    PropComparator, synonym, comparable_property, sessionmaker, \
    attributes, Session, backref, configure_mappers, foreign, deferred, defer
from sqlalchemy.orm.collections import attribute_mapped_collection
from sqlalchemy.orm.interfaces import MapperOption
from sqlalchemy.testing import eq_, in_, not_in_
from sqlalchemy.testing import fixtures
from test.orm import _fixtures
from sqlalchemy import event, and_, case
from sqlalchemy.testing.schema import Table, Column


class MergeTest(_fixtures.FixtureTest):
    """Session.merge() functionality"""

    run_inserts = None

    def load_tracker(self, cls, canary=None):
        if canary is None:
            def canary(instance, *args):
                canary.called += 1
            canary.called = 0

        event.listen(cls, 'load', canary)

        return canary

    def test_transient_to_pending(self):
        User, users = self.classes.User, self.tables.users

        mapper(User, users)
        sess = create_session()
        load = self.load_tracker(User)

        u = User(id=7, name='fred')
        eq_(load.called, 0)
        u2 = sess.merge(u)
        eq_(load.called, 1)
        assert u2 in sess
        eq_(u2, User(id=7, name='fred'))
        sess.flush()
        sess.expunge_all()
        eq_(sess.query(User).first(), User(id=7, name='fred'))

    def test_transient_to_pending_no_pk(self):
        """test that a transient object with no PK attribute
        doesn't trigger a needless load."""

        User, users = self.classes.User, self.tables.users

        mapper(User, users)
        sess = create_session()
        u = User(name='fred')

        def go():
            sess.merge(u)
        self.assert_sql_count(testing.db, go, 0)

    def test_transient_to_pending_collection(self):
        User, Address, addresses, users = (self.classes.User,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users)

        mapper(User, users, properties={
            'addresses': relationship(Address, backref='user',
                                      collection_class=OrderedSet)})
        mapper(Address, addresses)
        load = self.load_tracker(User)
        self.load_tracker(Address, load)

        u = User(id=7, name='fred', addresses=OrderedSet([
            Address(id=1, email_address='fred1'),
            Address(id=2, email_address='fred2'),
        ]))
        eq_(load.called, 0)

        sess = create_session()
        sess.merge(u)
        eq_(load.called, 3)

        merged_users = [e for e in sess if isinstance(e, User)]
        eq_(len(merged_users), 1)
        assert merged_users[0] is not u

        sess.flush()
        sess.expunge_all()

        eq_(sess.query(User).one(),
            User(id=7, name='fred', addresses=OrderedSet([
                Address(id=1, email_address='fred1'),
                Address(id=2, email_address='fred2'),
            ])))

    def test_transient_to_pending_collection_pk_none(self):
        User, Address, addresses, users = (self.classes.User,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users)

        mapper(User, users, properties={
            'addresses': relationship(Address, backref='user',
                                      collection_class=OrderedSet)})
        mapper(Address, addresses)
        load = self.load_tracker(User)
        self.load_tracker(Address, load)

        u = User(id=None, name='fred', addresses=OrderedSet([
            Address(id=None, email_address='fred1'),
            Address(id=None, email_address='fred2'),
        ]))
        eq_(load.called, 0)

        sess = create_session()
        sess.merge(u)
        eq_(load.called, 3)

        merged_users = [e for e in sess if isinstance(e, User)]
        eq_(len(merged_users), 1)
        assert merged_users[0] is not u

        sess.flush()
        sess.expunge_all()

        eq_(sess.query(User).one(),
            User(name='fred', addresses=OrderedSet([
                Address(email_address='fred1'),
                Address(email_address='fred2'),
            ])))

    def test_transient_to_persistent(self):
        User, users = self.classes.User, self.tables.users

        mapper(User, users)
        load = self.load_tracker(User)

        sess = create_session()
        u = User(id=7, name='fred')
        sess.add(u)
        sess.flush()
        sess.expunge_all()

        eq_(load.called, 0)

        _u2 = u2 = User(id=7, name='fred jones')
        eq_(load.called, 0)
        u2 = sess.merge(u2)
        assert u2 is not _u2
        eq_(load.called, 1)
        sess.flush()
        sess.expunge_all()
        eq_(sess.query(User).first(), User(id=7, name='fred jones'))
        eq_(load.called, 2)

    def test_transient_to_persistent_collection(self):
        User, Address, addresses, users = (self.classes.User,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users)

        mapper(User, users, properties={
            'addresses': relationship(Address,
                                      backref='user',
                                      collection_class=OrderedSet,
                                      order_by=addresses.c.id,
                                      cascade="all, delete-orphan")
        })
        mapper(Address, addresses)

        load = self.load_tracker(User)
        self.load_tracker(Address, load)

        u = User(id=7, name='fred', addresses=OrderedSet([
            Address(id=1, email_address='fred1'),
            Address(id=2, email_address='fred2'),
        ]))
        sess = create_session()
        sess.add(u)
        sess.flush()
        sess.expunge_all()

        eq_(load.called, 0)

        u = User(id=7, name='fred', addresses=OrderedSet([
            Address(id=3, email_address='fred3'),
            Address(id=4, email_address='fred4'),
        ]))

        u = sess.merge(u)

        # 1. merges User object.  updates into session.
        # 2.,3. merges Address ids 3 & 4, saves into session.
        # 4.,5. loads pre-existing elements in "addresses" collection,
        # marks as deleted, Address ids 1 and 2.
        eq_(load.called, 5)

        eq_(u,
            User(id=7, name='fred', addresses=OrderedSet([
                Address(id=3, email_address='fred3'),
                Address(id=4, email_address='fred4'),
            ])))
        sess.flush()
        sess.expunge_all()
        eq_(sess.query(User).one(),
            User(id=7, name='fred', addresses=OrderedSet([
                Address(id=3, email_address='fred3'),
                Address(id=4, email_address='fred4'),
            ])))

    def test_detached_to_persistent_collection(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(Address,
                                      backref='user',
                                      order_by=addresses.c.id,
                                      collection_class=OrderedSet)})
        mapper(Address, addresses)
        load = self.load_tracker(User)
        self.load_tracker(Address, load)

        a = Address(id=1, email_address='fred1')
        u = User(id=7, name='fred', addresses=OrderedSet([
            a,
            Address(id=2, email_address='fred2'),
        ]))
        sess = create_session()
        sess.add(u)
        sess.flush()
        sess.expunge_all()

        u.name = 'fred jones'
        u.addresses.add(Address(id=3, email_address='fred3'))
        u.addresses.remove(a)

        eq_(load.called, 0)
        u = sess.merge(u)
        eq_(load.called, 4)
        sess.flush()
        sess.expunge_all()

        eq_(sess.query(User).first(),
            User(id=7, name='fred jones', addresses=OrderedSet([
                Address(id=2, email_address='fred2'),
                Address(id=3, email_address='fred3')])))

    def test_unsaved_cascade(self):
        """Merge of a transient entity with two child transient
        entities, with a bidirectional relationship."""

        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      cascade="all", backref="user")
        })
        load = self.load_tracker(User)
        self.load_tracker(Address, load)
        sess = create_session()

        u = User(id=7, name='fred')
        a1 = Address(email_address='foo@bar.com')
        a2 = Address(email_address='hoho@bar.com')
        u.addresses.append(a1)
        u.addresses.append(a2)

        u2 = sess.merge(u)
        eq_(load.called, 3)

        eq_(u,
            User(id=7, name='fred', addresses=[
                Address(email_address='foo@bar.com'),
                Address(email_address='hoho@bar.com')]))
        eq_(u2,
            User(id=7, name='fred', addresses=[
                Address(email_address='foo@bar.com'),
                Address(email_address='hoho@bar.com')]))

        sess.flush()
        sess.expunge_all()
        u2 = sess.query(User).get(7)

        eq_(u2, User(id=7, name='fred', addresses=[
            Address(email_address='foo@bar.com'),
            Address(email_address='hoho@bar.com')]))
        eq_(load.called, 6)

    def test_merge_empty_attributes(self):
        User, dingalings = self.classes.User, self.tables.dingalings

        mapper(User, dingalings)

        sess = create_session()

        # merge empty stuff.  goes in as NULL.
        # not sure what this was originally trying to
        # test.
        u1 = sess.merge(User(id=1))
        sess.flush()
        assert u1.data is None

        # save another user with "data"
        u2 = User(id=2, data="foo")
        sess.add(u2)
        sess.flush()

        # merge User on u2's pk with
        # no "data".
        # value isn't whacked from the destination
        # dict.
        u3 = sess.merge(User(id=2))
        eq_(u3.__dict__['data'], "foo")

        # make a change.
        u3.data = 'bar'

        # merge another no-"data" user.
        # attribute maintains modified state.
        # (usually autoflush would have happened
        # here anyway).
        u4 = sess.merge(User(id=2))
        eq_(u3.__dict__['data'], "bar")

        sess.flush()
        # and after the flush.
        eq_(u3.data, "bar")

        # new row.
        u5 = User(id=3, data="foo")
        sess.add(u5)
        sess.flush()

        # blow it away from u5, but don't
        # mark as expired.  so it would just
        # be blank.
        del u5.data

        # the merge adds expiry to the
        # attribute so that it loads.
        # not sure if I like this - it currently is needed
        # for test_pickled:PickleTest.test_instance_deferred_cols
        u6 = sess.merge(User(id=3))
        assert 'data' not in u6.__dict__
        assert u6.data == "foo"

        # set it to None.  this is actually
        # a change so gets preserved.
        u6.data = None
        u7 = sess.merge(User(id=3))
        assert u6.__dict__['data'] is None

    def test_merge_irregular_collection(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(
                mapper(Address, addresses),
                backref='user',
                collection_class=attribute_mapped_collection('email_address')),
        })
        u1 = User(id=7, name='fred')
        u1.addresses['foo@bar.com'] = Address(email_address='foo@bar.com')
        sess = create_session()
        sess.merge(u1)
        sess.flush()
        assert list(u1.addresses.keys()) == ['foo@bar.com']

    def test_attribute_cascade(self):
        """Merge of a persistent entity with two child
        persistent entities."""

        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      backref='user')
        })
        load = self.load_tracker(User)
        self.load_tracker(Address, load)

        sess = create_session()

        # set up data and save
        u = User(id=7, name='fred', addresses=[
            Address(email_address='foo@bar.com'),
            Address(email_address='hoho@la.com')])
        sess.add(u)
        sess.flush()

        # assert data was saved
        sess2 = create_session()
        u2 = sess2.query(User).get(7)
        eq_(u2,
            User(id=7, name='fred', addresses=[
                Address(email_address='foo@bar.com'),
                Address(email_address='hoho@la.com')]))

        # make local changes to data
        u.name = 'fred2'
        u.addresses[1].email_address = 'hoho@lalala.com'

        eq_(load.called, 3)

        # new session, merge modified data into session
        sess3 = create_session()
        u3 = sess3.merge(u)
        eq_(load.called, 6)

        # ensure local changes are pending
        eq_(u3, User(id=7, name='fred2', addresses=[
            Address(email_address='foo@bar.com'),
            Address(email_address='hoho@lalala.com')]))

        # save merged data
        sess3.flush()

        # assert modified/merged data was saved
        sess.expunge_all()
        u = sess.query(User).get(7)
        eq_(u, User(id=7, name='fred2', addresses=[
            Address(email_address='foo@bar.com'),
            Address(email_address='hoho@lalala.com')]))
        eq_(load.called, 9)

        # merge persistent object into another session
        sess4 = create_session()
        u = sess4.merge(u)
        assert len(u.addresses)
        for a in u.addresses:
            assert a.user is u

        def go():
            sess4.flush()
        # no changes; therefore flush should do nothing
        self.assert_sql_count(testing.db, go, 0)
        eq_(load.called, 12)

        # test with "dontload" merge
        sess5 = create_session()
        u = sess5.merge(u, load=False)
        assert len(u.addresses)
        for a in u.addresses:
            assert a.user is u

        def go():
            sess5.flush()
        # no changes; therefore flush should do nothing
        # but also, load=False wipes out any difference in committed state,
        # so no flush at all
        self.assert_sql_count(testing.db, go, 0)
        eq_(load.called, 15)

        sess4 = create_session()
        u = sess4.merge(u, load=False)
        # post merge change
        u.addresses[1].email_address = 'afafds'

        def go():
            sess4.flush()
        # afafds change flushes
        self.assert_sql_count(testing.db, go, 1)
        eq_(load.called, 18)

        sess5 = create_session()
        u2 = sess5.query(User).get(u.id)
        eq_(u2.name, 'fred2')
        eq_(u2.addresses[1].email_address, 'afafds')
        eq_(load.called, 21)

    def test_dont_send_neverset_to_get(self):
        # test issue #3647
        CompositePk, composite_pk_table = (
            self.classes.CompositePk, self.tables.composite_pk_table
        )
        mapper(CompositePk, composite_pk_table)
        cp1 = CompositePk(j=1, k=1)

        sess = Session()

        rec = []

        def go():
            rec.append(sess.merge(cp1))
        self.assert_sql_count(testing.db, go, 0)
        rec[0].i = 5
        sess.commit()
        eq_(rec[0].i, 5)

    def test_dont_send_neverset_to_get_w_relationship(self):
        # test issue #3647
        CompositePk, composite_pk_table = (
            self.classes.CompositePk, self.tables.composite_pk_table
        )
        User, users = (
            self.classes.User, self.tables.users
        )
        mapper(User, users, properties={
            'elements': relationship(
                CompositePk,
                primaryjoin=users.c.id == foreign(composite_pk_table.c.i))
        })
        mapper(CompositePk, composite_pk_table)

        u1 = User(id=5, name='some user')
        cp1 = CompositePk(j=1, k=1)
        u1.elements.append(cp1)
        sess = Session()

        rec = []

        def go():
            rec.append(sess.merge(u1))
        self.assert_sql_count(testing.db, go, 1)
        u2 = rec[0]
        sess.commit()
        eq_(u2.elements[0].i, 5)
        eq_(u2.id, 5)

    def test_no_relationship_cascade(self):
        """test that merge doesn't interfere with a relationship()
           target that specifically doesn't include 'merge' cascade.
        """

        Address, addresses, users, User = (self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users,
                                           self.classes.User)

        mapper(Address, addresses, properties={
            'user': relationship(User, cascade="save-update")
        })
        mapper(User, users)
        sess = create_session()
        u1 = User(name="fred")
        a1 = Address(email_address="asdf", user=u1)
        sess.add(a1)
        sess.flush()

        a2 = Address(id=a1.id, email_address="bar", user=User(name="hoho"))
        a2 = sess.merge(a2)
        sess.flush()

        # no expire of the attribute

        assert a2.__dict__['user'] is u1

        # merge succeeded
        eq_(
            sess.query(Address).all(),
            [Address(id=a1.id, email_address="bar")]
        )

        # didn't touch user
        eq_(
            sess.query(User).all(),
            [User(name="fred")]
        )

    def test_one_to_many_cascade(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses))})

        load = self.load_tracker(User)
        self.load_tracker(Address, load)

        sess = create_session()
        u = User(name='fred')
        a1 = Address(email_address='foo@bar')
        a2 = Address(email_address='foo@quux')
        u.addresses.extend([a1, a2])

        sess.add(u)
        sess.flush()

        eq_(load.called, 0)

        sess2 = create_session()
        u2 = sess2.query(User).get(u.id)
        eq_(load.called, 1)

        u.addresses[1].email_address = 'addr 2 modified'
        sess2.merge(u)
        eq_(u2.addresses[1].email_address, 'addr 2 modified')
        eq_(load.called, 3)

        sess3 = create_session()
        u3 = sess3.query(User).get(u.id)
        eq_(load.called, 4)

        u.name = 'also fred'
        sess3.merge(u)
        eq_(load.called, 6)
        eq_(u3.name, 'also fred')

    def test_many_to_one_cascade(self):
        Address, addresses, users, User = (self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users,
                                           self.classes.User)

        mapper(Address, addresses, properties={
            'user': relationship(User)
        })
        mapper(User, users)

        u1 = User(id=1, name="u1")
        a1 = Address(id=1, email_address="a1", user=u1)
        u2 = User(id=2, name="u2")

        sess = create_session()
        sess.add_all([a1, u2])
        sess.flush()

        a1.user = u2

        sess2 = create_session()
        a2 = sess2.merge(a1)
        eq_(
            attributes.get_history(a2, 'user'),
            ([u2], (), ())
        )
        assert a2 in sess2.dirty

        sess.refresh(a1)

        sess2 = create_session()
        a2 = sess2.merge(a1, load=False)
        eq_(
            attributes.get_history(a2, 'user'),
            ((), [u1], ())
        )
        assert a2 not in sess2.dirty

    def test_many_to_many_cascade(self):
        items, Order, orders, order_items, Item = (self.tables.items,
                                                   self.classes.Order,
                                                   self.tables.orders,
                                                   self.tables.order_items,
                                                   self.classes.Item)

        mapper(Order, orders, properties={
            'items': relationship(mapper(Item, items),
                                  secondary=order_items)})

        load = self.load_tracker(Order)
        self.load_tracker(Item, load)

        sess = create_session()

        i1 = Item()
        i1.description = 'item 1'

        i2 = Item()
        i2.description = 'item 2'

        o = Order()
        o.description = 'order description'
        o.items.append(i1)
        o.items.append(i2)

        sess.add(o)
        sess.flush()

        eq_(load.called, 0)

        sess2 = create_session()
        o2 = sess2.query(Order).get(o.id)
        eq_(load.called, 1)

        o.items[1].description = 'item 2 modified'
        sess2.merge(o)
        eq_(o2.items[1].description, 'item 2 modified')
        eq_(load.called,  3)

        sess3 = create_session()
        o3 = sess3.query(Order).get(o.id)
        eq_(load.called, 4)

        o.description = 'desc modified'
        sess3.merge(o)
        eq_(load.called, 6)
        eq_(o3.description, 'desc modified')

    def test_one_to_one_cascade(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'address': relationship(mapper(Address, addresses),
                                    uselist=False)
        })
        load = self.load_tracker(User)
        self.load_tracker(Address, load)
        sess = create_session()

        u = User()
        u.id = 7
        u.name = "fred"
        a1 = Address()
        a1.email_address = 'foo@bar.com'
        u.address = a1

        sess.add(u)
        sess.flush()

        eq_(load.called, 0)

        sess2 = create_session()
        u2 = sess2.query(User).get(7)
        eq_(load.called, 1)
        u2.name = 'fred2'
        u2.address.email_address = 'hoho@lalala.com'
        eq_(load.called, 2)

        u3 = sess.merge(u2)
        eq_(load.called, 2)
        assert u3 is u

    def test_value_to_none(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'address': relationship(mapper(Address, addresses),
                                    uselist=False, backref='user')
        })
        sess = sessionmaker()()
        u = User(id=7, name="fred",
                 address=Address(id=1, email_address='foo@bar.com'))
        sess.add(u)
        sess.commit()
        sess.close()

        u2 = User(id=7, name=None, address=None)
        u3 = sess.merge(u2)
        assert u3.name is None
        assert u3.address is None

        sess.close()

        a1 = Address(id=1, user=None)
        a2 = sess.merge(a1)
        assert a2.user is None

    def test_transient_no_load(self):
        users, User = self.tables.users, self.classes.User

        mapper(User, users)

        sess = create_session()
        u = User()
        assert_raises_message(sa.exc.InvalidRequestError,
                              "load=False option does not support",
                              sess.merge, u, load=False)

    def test_no_load_with_backrefs(self):
        """load=False populates relationships in both
        directions without requiring a load"""

        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      backref='user')
        })

        u = User(id=7, name='fred', addresses=[
            Address(email_address='ad1'),
            Address(email_address='ad2')])
        sess = create_session()
        sess.add(u)
        sess.flush()
        sess.close()
        assert 'user' in u.addresses[1].__dict__

        sess = create_session()
        u2 = sess.merge(u, load=False)
        assert 'user' in u2.addresses[1].__dict__
        eq_(u2.addresses[1].user, User(id=7, name='fred'))

        sess.expire(u2.addresses[1], ['user'])
        assert 'user' not in u2.addresses[1].__dict__
        sess.close()

        sess = create_session()
        u = sess.merge(u2, load=False)
        assert 'user' not in u.addresses[1].__dict__
        eq_(u.addresses[1].user, User(id=7, name='fred'))

    def test_dontload_with_eager(self):
        """

        This test illustrates that with load=False, we can't just copy
        the committed_state of the merged instance over; since it
        references collection objects which themselves are to be merged.
        This committed_state would instead need to be piecemeal
        'converted' to represent the correct objects.  However, at the
        moment I'd rather not support this use case; if you are merging
        with load=False, you're typically dealing with caching and the
        merged objects shouldn't be 'dirty'.

        """

        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses))
        })
        sess = create_session()
        u = User()
        u.id = 7
        u.name = "fred"
        a1 = Address()
        a1.email_address = 'foo@bar.com'
        u.addresses.append(a1)

        sess.add(u)
        sess.flush()

        sess2 = create_session()
        u2 = sess2.query(User).\
            options(sa.orm.joinedload('addresses')).get(7)

        sess3 = create_session()
        u3 = sess3.merge(u2, load=False)

        def go():
            sess3.flush()
        self.assert_sql_count(testing.db, go, 0)

    def test_no_load_disallows_dirty(self):
        """load=False doesn't support 'dirty' objects right now

        (see test_no_load_with_eager()). Therefore lets assert it.

        """

        users, User = self.tables.users, self.classes.User

        mapper(User, users)
        sess = create_session()
        u = User()
        u.id = 7
        u.name = "fred"
        sess.add(u)
        sess.flush()

        u.name = 'ed'
        sess2 = create_session()
        try:
            sess2.merge(u, load=False)
            assert False
        except sa.exc.InvalidRequestError as e:
            assert "merge() with load=False option does not support "\
                "objects marked as 'dirty'.  flush() all changes on "\
                "mapped instances before merging with load=False." \
                in str(e)

        u2 = sess2.query(User).get(7)

        sess3 = create_session()
        u3 = sess3.merge(u2, load=False)
        assert not sess3.dirty

        def go():
            sess3.flush()
        self.assert_sql_count(testing.db, go, 0)

    def test_no_load_sets_backrefs(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      backref='user')})

        sess = create_session()
        u = User()
        u.id = 7
        u.name = "fred"
        a1 = Address()
        a1.email_address = 'foo@bar.com'
        u.addresses.append(a1)

        sess.add(u)
        sess.flush()

        assert u.addresses[0].user is u

        sess2 = create_session()
        u2 = sess2.merge(u, load=False)
        assert not sess2.dirty

        def go():
            assert u2.addresses[0].user is u2
        self.assert_sql_count(testing.db, go, 0)

    def test_no_load_preserves_parents(self):
        """Merge with load=False does not trigger a 'delete-orphan'
        operation.

        merge with load=False sets attributes without using events.
        this means the 'hasparent' flag is not propagated to the newly
        merged instance. in fact this works out OK, because the
        '_state.parents' collection on the newly merged instance is
        empty; since the mapper doesn't see an active 'False' setting in
        this collection when _is_orphan() is called, it does not count
        as an orphan (i.e. this is the 'optimistic' logic in
        mapper._is_orphan().)

        """

        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      backref='user',
                                      cascade="all, delete-orphan")})
        sess = create_session()
        u = User()
        u.id = 7
        u.name = "fred"
        a1 = Address()
        a1.email_address = 'foo@bar.com'
        u.addresses.append(a1)
        sess.add(u)
        sess.flush()

        assert u.addresses[0].user is u

        sess2 = create_session()
        u2 = sess2.merge(u, load=False)
        assert not sess2.dirty
        a2 = u2.addresses[0]
        a2.email_address = 'somenewaddress'
        assert not sa.orm.object_mapper(a2)._is_orphan(
            sa.orm.attributes.instance_state(a2))
        sess2.flush()
        sess2.expunge_all()

        eq_(sess2.query(User).get(u2.id).addresses[0].email_address,
            'somenewaddress')

        # this use case is not supported; this is with a pending Address
        # on the pre-merged object, and we currently don't support
        # 'dirty' objects being merged with load=False.  in this case,
        # the empty '_state.parents' collection would be an issue, since
        # the optimistic flag is False in _is_orphan() for pending
        # instances.  so if we start supporting 'dirty' with load=False,
        # this test will need to pass

        sess = create_session()
        u = sess.query(User).get(7)
        u.addresses.append(Address())
        sess2 = create_session()
        try:
            u2 = sess2.merge(u, load=False)
            assert False

            # if load=False is changed to support dirty objects, this code
            # needs to pass
            a2 = u2.addresses[0]
            a2.email_address = 'somenewaddress'
            assert not sa.orm.object_mapper(a2)._is_orphan(
                sa.orm.attributes.instance_state(a2))
            sess2.flush()
            sess2.expunge_all()
            eq_(sess2.query(User).get(u2.id).addresses[0].email_address,
                'somenewaddress')
        except sa.exc.InvalidRequestError as e:
            assert "load=False option does not support" in str(e)

    def test_synonym_comparable(self):
        users = self.tables.users

        class User(object):

            class Comparator(PropComparator):
                pass

            def _getValue(self):
                return self._value

            def _setValue(self, value):
                setattr(self, '_value', value)

            value = property(_getValue, _setValue)

        mapper(User, users, properties={
            'uid': synonym('id'),
            'foobar': comparable_property(User.Comparator, User.value),
        })

        sess = create_session()
        u = User()
        u.name = 'ed'
        sess.add(u)
        sess.flush()
        sess.expunge(u)
        sess.merge(u)

    def test_cascade_doesnt_blowaway_manytoone(self):
        """a merge test that was fixed by [ticket:1202]"""

        User, Address, addresses, users = (self.classes.User,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users)

        s = create_session(autoflush=True, autocommit=False)
        mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      backref='user')})

        a1 = Address(user=s.merge(User(id=1, name='ed')), email_address='x')
        before_id = id(a1.user)
        a2 = Address(user=s.merge(User(id=1, name='jack')),
                     email_address='x')
        after_id = id(a1.user)
        other_id = id(a2.user)
        eq_(before_id, other_id)
        eq_(after_id, other_id)
        eq_(before_id, after_id)
        eq_(a1.user, a2.user)

    def test_cascades_dont_autoflush(self):
        User, Address, addresses, users = (self.classes.User,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.tables.users)

        sess = create_session(autoflush=True, autocommit=False)
        m = mapper(User, users, properties={
            'addresses': relationship(mapper(Address, addresses),
                                      backref='user')})
        user = User(id=8, name='fred',
                    addresses=[Address(email_address='user')])
        merged_user = sess.merge(user)
        assert merged_user in sess.new
        sess.flush()
        assert merged_user not in sess.new

    def test_cascades_dont_autoflush_2(self):
        users, Address, addresses, User = (self.tables.users,
                                           self.classes.Address,
                                           self.tables.addresses,
                                           self.classes.User)

        mapper(User, users, properties={
            'addresses': relationship(Address,
                                      backref='user',
                                      cascade="all, delete-orphan")
        })
        mapper(Address, addresses)

        u = User(id=7, name='fred', addresses=[
            Address(id=1, email_address='fred1'),
        ])
        sess = create_session(autoflush=True, autocommit=False)
        sess.add(u)
        sess.commit()

        sess.expunge_all()

        u = User(id=7, name='fred', addresses=[
            Address(id=1, email_address='fred1'),
            Address(id=2, email_address='fred2'),
        ])
        sess.merge(u)
        assert sess.autoflush
        sess.commit()

    def test_dont_expire_pending(self):
        """test that pending instances aren't expired during a merge."""

        users, User = self.tables.users, self.classes.User

        mapper(User, users)
        u = User(id=7)
        sess = create_session(autoflush=True, autocommit=False)
        u = sess.merge(u)
        assert not bool(attributes.instance_state(u).expired_attributes)

        def go():
            eq_(u.name, None)
        self.assert_sql_count(testing.db, go, 0)

    def test_option_state(self):
        """test that the merged takes on the MapperOption characteristics
        of that which is merged.

        """

        users, User = self.tables.users, self.classes.User

        class Option(MapperOption):
            propagate_to_loaders = True

        opt1, opt2 = Option(), Option()

        sess = sessionmaker()()

        umapper = mapper(User, users)

        sess.add_all([
            User(id=1, name='u1'),
            User(id=2, name='u2'),
        ])
        sess.commit()

        sess2 = sessionmaker()()
        s2_users = sess2.query(User).options(opt2).all()

        # test 1.  no options are replaced by merge options
        sess = sessionmaker()()
        s1_users = sess.query(User).all()

        for u in s1_users:
            ustate = attributes.instance_state(u)
            eq_(ustate.load_path.path, (umapper, ))
            eq_(ustate.load_options, set())

        for u in s2_users:
            sess.merge(u)

        for u in s1_users:
            ustate = attributes.instance_state(u)
            eq_(ustate.load_path.path, (umapper, ))
            eq_(ustate.load_options, set([opt2]))

        # test 2.  present options are replaced by merge options
        sess = sessionmaker()()
        s1_users = sess.query(User).options(opt1).all()
        for u in s1_users:
            ustate = attributes.instance_state(u)
            eq_(ustate.load_path.path, (umapper, ))
            eq_(ustate.load_options, set([opt1]))

        for u in s2_users:
            sess.merge(u)

        for u in s1_users:
            ustate = attributes.instance_state(u)
            eq_(ustate.load_path.path, (umapper, ))
            eq_(ustate.load_options, set([opt2]))

    def test_resolve_conflicts_pending_doesnt_interfere_no_ident(self):
        User, Address, Order = (
            self.classes.User, self.classes.Address, self.classes.Order)
        users, addresses, orders = (
            self.tables.users, self.tables.addresses, self.tables.orders)

        mapper(User, users, properties={
            'orders': relationship(Order)
        })
        mapper(Order, orders, properties={
            'address': relationship(Address)
        })
        mapper(Address, addresses)

        u1 = User(id=7, name='x')
        u1.orders = [
            Order(description='o1', address=Address(email_address='a')),
            Order(description='o2', address=Address(email_address='b')),
            Order(description='o3', address=Address(email_address='c'))
        ]

        sess = Session()
        sess.merge(u1)
        sess.flush()

        eq_(
            sess.query(Address.email_address).order_by(
                Address.email_address).all(),
            [('a', ), ('b', ), ('c', )]
        )

    def test_resolve_conflicts_pending(self):
        User, Address, Order = (
            self.classes.User, self.classes.Address, self.classes.Order)
        users, addresses, orders = (
            self.tables.users, self.tables.addresses, self.tables.orders)

        mapper(User, users, properties={
            'orders': relationship(Order)
        })
        mapper(Order, orders, properties={
            'address': relationship(Address)
        })
        mapper(Address, addresses)

        u1 = User(id=7, name='x')
        u1.orders = [
            Order(description='o1', address=Address(id=1, email_address='a')),
            Order(description='o2', address=Address(id=1, email_address='b')),
            Order(description='o3', address=Address(id=1, email_address='c'))
        ]

        sess = Session()
        sess.merge(u1)
        sess.flush()

        eq_(
            sess.query(Address).one(),
            Address(id=1, email_address='c')
        )

    def test_resolve_conflicts_persistent(self):
        User, Address, Order = (
            self.classes.User, self.classes.Address, self.classes.Order)
        users, addresses, orders = (
            self.tables.users, self.tables.addresses, self.tables.orders)

        mapper(User, users, properties={
            'orders': relationship(Order)
        })
        mapper(Order, orders, properties={
            'address': relationship(Address)
        })
        mapper(Address, addresses)

        sess = Session()
        sess.add(Address(id=1, email_address='z'))
        sess.commit()

        u1 = User(id=7, name='x')
        u1.orders = [
            Order(description='o1', address=Address(id=1, email_address='a')),
            Order(description='o2', address=Address(id=1, email_address='b')),
            Order(description='o3', address=Address(id=1, email_address='c'))
        ]

        sess = Session()
        sess.merge(u1)
        sess.flush()

        eq_(
            sess.query(Address).one(),
            Address(id=1, email_address='c')
        )


class M2ONoUseGetLoadingTest(fixtures.MappedTest):
    """Merge a one-to-many.  The many-to-one on the other side is set up
    so that use_get is False.   See if skipping the "m2o" merge
    vs. doing it saves on SQL calls.

    """

    @classmethod
    def define_tables(cls, metadata):
        Table('user', metadata,
              Column('id', Integer, primary_key=True,
                     test_needs_autoincrement=True),
              Column('name', String(50)))
        Table('address', metadata,
              Column('id', Integer, primary_key=True,
                     test_needs_autoincrement=True),
              Column('user_id', Integer, ForeignKey('user.id')),
              Column('email', String(50)))

    @classmethod
    def setup_classes(cls):
        class User(cls.Comparable):
            pass

        class Address(cls.Comparable):
            pass

    @classmethod
    def setup_mappers(cls):
        User, Address = cls.classes.User, cls.classes.Address
        user, address = cls.tables.user, cls.tables.address
        mapper(User, user, properties={
            'addresses': relationship(Address,
                                      backref=backref(
                                          'user',
                                          # needlessly complex primaryjoin so
                                          # that the use_get flag is False
                                          primaryjoin=and_(
                                              user.c.id == address.c.user_id,
                                              user.c.id == user.c.id
                                          )))
        })
        mapper(Address, address)
        configure_mappers()
        assert Address.user.property._use_get is False

    @classmethod
    def insert_data(cls):
        User, Address = cls.classes.User, cls.classes.Address
        s = Session()
        s.add_all([
            User(id=1, name='u1', addresses=[Address(id=1, email='a1'),
                                             Address(id=2, email='a2')])
        ])
        s.commit()

    # "persistent" - we get at an Address that was already present.
    # With the "skip bidirectional" check removed, the "set" emits SQL
    # for the "previous" version in any case,
    # address.user_id is 1, you get a load.
    def test_persistent_access_none(self):
        User, Address = self.classes.User, self.classes.Address
        s = Session()

        def go():
            u1 = User(id=1, addresses=[Address(id=1), Address(id=2)])
            u2 = s.merge(u1)
        self.assert_sql_count(testing.db, go, 2)

    def test_persistent_access_one(self):
        User, Address = self.classes.User, self.classes.Address
        s = Session()

        def go():
            u1 = User(id=1, addresses=[Address(id=1), Address(id=2)])
            u2 = s.merge(u1)
            a1 = u2.addresses[0]
            assert a1.user is u2
        self.assert_sql_count(testing.db, go, 3)

    def test_persistent_access_two(self):
        User, Address = self.classes.User, self.classes.Address
        s = Session()

        def go():
            u1 = User(id=1, addresses=[Address(id=1), Address(id=2)])
            u2 = s.merge(u1)
            a1 = u2.addresses[0]
            assert a1.user is u2
            a2 = u2.addresses[1]
            assert a2.user is u2
        self.assert_sql_count(testing.db, go, 4)

    # "pending" - we get at an Address that is new- user_id should be
    # None.  But in this case the set attribute on the forward side
    # already sets the backref.  commenting out the "skip bidirectional"
    # check emits SQL again for the other two Address objects already
    # persistent.
    def test_pending_access_one(self):
        User, Address = self.classes.User, self.classes.Address
        s = Session()

        def go():
            u1 = User(id=1,
                      addresses=[Address(id=1), Address(id=2),
                                 Address(id=3, email='a3')])
            u2 = s.merge(u1)
            a3 = u2.addresses[2]
            assert a3.user is u2
        self.assert_sql_count(testing.db, go, 3)

    def test_pending_access_two(self):
        User, Address = self.classes.User, self.classes.Address
        s = Session()

        def go():
            u1 = User(id=1,
                      addresses=[Address(id=1), Address(id=2),
                                 Address(id=3, email='a3')])
            u2 = s.merge(u1)
            a3 = u2.addresses[2]
            assert a3.user is u2
            a2 = u2.addresses[1]
            assert a2.user is u2
        self.assert_sql_count(testing.db, go, 5)


class DeferredMergeTest(fixtures.MappedTest):
    @classmethod
    def define_tables(cls, metadata):
        Table(
            'book', metadata,
            Column('id', Integer, primary_key=True),
            Column('title', String(200), nullable=False),
            Column('summary', String(2000)),
            Column('excerpt', Text),
        )

    @classmethod
    def setup_classes(cls):
        class Book(cls.Basic):
            pass

    def test_deferred_column_mapping(self):
        # defer 'excerpt' at mapping level instead of query level
        Book, book = self.classes.Book, self.tables.book
        mapper(Book, book, properties={'excerpt': deferred(book.c.excerpt)})
        sess = sessionmaker()()

        b = Book(
            id=1,
            title='Essential SQLAlchemy',
            summary='some summary',
            excerpt='some excerpt',
        )
        sess.add(b)
        sess.commit()

        b1 = sess.query(Book).first()
        sess.expire(b1, ['summary'])
        sess.close()

        def go():
            b2 = sess.merge(b1, load=False)

            # should not emit load for deferred 'excerpt'
            eq_(b2.summary, 'some summary')
            not_in_('excerpt', b2.__dict__)

            # now it should emit load for deferred 'excerpt'
            eq_(b2.excerpt, 'some excerpt')
            in_('excerpt', b2.__dict__)

        self.sql_eq_(go, [
            ("SELECT book.summary AS book_summary "
             "FROM book WHERE book.id = :param_1",
             {'param_1': 1}),
            ("SELECT book.excerpt AS book_excerpt "
             "FROM book WHERE book.id = :param_1",
             {'param_1': 1})
        ])

    def test_deferred_column_query(self):
        Book, book = self.classes.Book, self.tables.book
        mapper(Book, book)
        sess = sessionmaker()()

        b = Book(
            id=1,
            title='Essential SQLAlchemy',
            summary='some summary',
            excerpt='some excerpt',
        )
        sess.add(b)
        sess.commit()

        # defer 'excerpt' at query level instead of mapping level
        b1 = sess.query(Book).options(defer(Book.excerpt)).first()
        sess.expire(b1, ['summary'])
        sess.close()

        def go():
            b2 = sess.merge(b1, load=False)

            # should not emit load for deferred 'excerpt'
            eq_(b2.summary, 'some summary')
            not_in_('excerpt', b2.__dict__)

            # now it should emit load for deferred 'excerpt'
            eq_(b2.excerpt, 'some excerpt')
            in_('excerpt', b2.__dict__)

        self.sql_eq_(go, [
            ("SELECT book.summary AS book_summary "
             "FROM book WHERE book.id = :param_1",
             {'param_1': 1}),
            ("SELECT book.excerpt AS book_excerpt "
             "FROM book WHERE book.id = :param_1",
             {'param_1': 1})
        ])


class MutableMergeTest(fixtures.MappedTest):
    @classmethod
    def define_tables(cls, metadata):
        Table("data", metadata,
              Column('id', Integer, primary_key=True,
                     test_needs_autoincrement=True),
              Column('data', PickleType(comparator=operator.eq)))

    @classmethod
    def setup_classes(cls):
        class Data(cls.Basic):
            pass

    def test_list(self):
        Data, data = self.classes.Data, self.tables.data

        mapper(Data, data)
        sess = sessionmaker()()
        d = Data(data=["this", "is", "a", "list"])

        sess.add(d)
        sess.commit()

        d2 = Data(id=d.id, data=["this", "is", "another", "list"])
        d3 = sess.merge(d2)
        eq_(d3.data, ["this", "is", "another", "list"])


class CompositeNullPksTest(fixtures.MappedTest):
    @classmethod
    def define_tables(cls, metadata):
        Table("data", metadata,
              Column('pk1', String(10), primary_key=True),
              Column('pk2', String(10), primary_key=True))

    @classmethod
    def setup_classes(cls):
        class Data(cls.Basic):
            pass

    def test_merge_allow_partial(self):
        Data, data = self.classes.Data, self.tables.data

        mapper(Data, data)
        sess = sessionmaker()()

        d1 = Data(pk1="someval", pk2=None)

        def go():
            return sess.merge(d1)
        self.assert_sql_count(testing.db, go, 1)

    def test_merge_disallow_partial(self):
        Data, data = self.classes.Data, self.tables.data

        mapper(Data, data, allow_partial_pks=False)
        sess = sessionmaker()()

        d1 = Data(pk1="someval", pk2=None)

        def go():
            return sess.merge(d1)
        self.assert_sql_count(testing.db, go, 0)


class LoadOnPendingTest(fixtures.MappedTest):
    """Test interaction of merge() with load_on_pending relationships"""
    @classmethod
    def define_tables(cls, metadata):
        rocks_table = Table("rocks", metadata,
                            Column("id", Integer, primary_key=True),
                            Column("description", String(10)))
        bugs_table = Table("bugs", metadata,
                           Column("id", Integer, primary_key=True),
                           Column("rockid", Integer, ForeignKey('rocks.id')))

    @classmethod
    def setup_classes(cls):
        class Rock(cls.Basic, fixtures.ComparableEntity):
            pass

        class Bug(cls.Basic, fixtures.ComparableEntity):
            pass

    def _setup_delete_orphan_o2o(self):
        mapper(self.classes.Rock, self.tables.rocks,
               properties={'bug': relationship(self.classes.Bug,
                                               cascade='all,delete-orphan',
                                               load_on_pending=True,
                                               uselist=False)
                           })
        mapper(self.classes.Bug, self.tables.bugs)
        self.sess = sessionmaker()()

    def _merge_delete_orphan_o2o_with(self, bug):
        # create a transient rock with passed bug
        r = self.classes.Rock(id=0, description='moldy')
        r.bug = bug
        m = self.sess.merge(r)
        # we've already passed ticket #2374 problem since merge() returned,
        # but for good measure:
        assert m is not r
        eq_(m, r)

    def test_merge_delete_orphan_o2o_none(self):
        """one to one delete_orphan relationships marked load_on_pending
        should be able to merge() with attribute None"""

        self._setup_delete_orphan_o2o()
        self._merge_delete_orphan_o2o_with(None)

    def test_merge_delete_orphan_o2o(self):
        """one to one delete_orphan relationships marked load_on_pending
        should be able to merge()"""

        self._setup_delete_orphan_o2o()
        self._merge_delete_orphan_o2o_with(self.classes.Bug(id=1))


class PolymorphicOnTest(fixtures.MappedTest):
    """Test merge() of polymorphic object when polymorphic_on
    isn't a Column"""

    @classmethod
    def define_tables(cls, metadata):
        Table('employees', metadata,
              Column('employee_id', Integer, primary_key=True,
                     test_needs_autoincrement=True),
              Column('type', String(1), nullable=False),
              Column('data', String(50)))

    @classmethod
    def setup_classes(cls):
        class Employee(cls.Basic, fixtures.ComparableEntity):
            pass

        class Manager(Employee):
            pass

        class Engineer(Employee):
            pass

    def _setup_polymorphic_on_mappers(self):
        employee_mapper = mapper(self.classes.Employee,
                                 self.tables.employees,
                                 polymorphic_on=case(
                                     value=self.tables.employees.c.type,
                                     whens={
                                         'E': 'employee',
                                         'M': 'manager',
                                         'G': 'engineer',
                                         'R': 'engineer',
                                     }),
                                 polymorphic_identity='employee')
        mapper(self.classes.Manager, inherits=employee_mapper,
               polymorphic_identity='manager')
        mapper(self.classes.Engineer, inherits=employee_mapper,
               polymorphic_identity='engineer')
        self.sess = sessionmaker()()

    def test_merge_polymorphic_on(self):
        """merge() should succeed with a polymorphic object even when
        polymorphic_on is not a Column
        """
        self._setup_polymorphic_on_mappers()

        m = self.classes.Manager(employee_id=55, type='M',
                                 data='original data')
        self.sess.add(m)
        self.sess.commit()
        self.sess.expunge_all()

        m = self.classes.Manager(employee_id=55, data='updated data')
        merged = self.sess.merge(m)

        # we've already passed ticket #2449 problem since
        # merge() returned, but for good measure:
        assert m is not merged
        eq_(m, merged)