Gnu Mailman 3 uses SQL Alchemy to access SQL databases. We have an issue
with one of or unit tests which passes with SQLAlchemy <= 1.1.15 but which
fails with SQLAlchemy >= 1.2. The failure is independent of the backend
(sglite, mysql or pgsql). Here's a traceback from the failure.
Traceback (most recent call last):
File "/builds/mailman/mailman/src/mailman/model/tests/test_user.py", line
184, in test_absorb_memberships
all_users = list(self._manager.users)
File "/builds/mailman/mailman/src/mailman/model/usermanager.py", line 102, in
users
yield from store.query(User).order_by(User.id).all()
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/query.py",
line 2726, in all
return list(self)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/query.py",
line 2877, in __iter__
self.session._autoflush()
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/session.py",
line 1434, in _autoflush
self.flush()
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/session.py",
line 2243, in flush
self._flush(objects)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/session.py",
line 2369, in _flush
transaction.rollback(_capture_exception=True)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py",
line 66, in __exit__
compat.reraise(exc_type, exc_value, exc_tb)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/util/compat.py",
line 187, in reraise
raise value
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/session.py",
line 2333, in _flush
flush_context.execute()
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/unitofwork.py",
line 391, in execute
rec.execute(self)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/unitofwork.py",
line 542, in execute
persistence.post_update(self.mapper, states, uow, cols)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/persistence.py",
line 234, in post_update
mapper, table, update)
File
"/builds/mailman/mailman/.tox/py36-nocov/lib/python3.6/site-packages/sqlalchemy/orm/persistence.py",
line 982, in _emit_post_update_statements
(table.description, len(records), rows))
sqlalchemy.orm.exc.StaleDataError: UPDATE statement on table 'user' expected to
update 1 row(s); 0 were matched.
The test that fails sets up 3 mailing lists and subscribes 2 users (Anne
and Bart) to some or all of the lists with different roles. Then user Anne
"absorbs" user Bart so user Bart is deleted and user Anne assumes all
Bart's memberships. The actual code in the test may not be intelligible
without more Mailman knowledge, but it is:
def test_absorb_memberships(self):
# When a user is absorbed, all of their user-subscribed memberships
# are relinked to the absorbing user.
mlist2 = create_list('[email protected]')
mlist3 = create_list('[email protected]')
with transaction():
# This has to happen in a transaction so that both the user and
# the preferences objects get valid ids.
bart = self._manager.create_user('[email protected]', 'Bart
Person')
set_preferred(bart)
# Subscribe both users to self._mlist.
self._mlist.subscribe(self._anne, MemberRole.member)
self._mlist.subscribe(bart, MemberRole.moderator)
# Subscribe only Bart to mlist2.
mlist2.subscribe(bart, MemberRole.owner)
# Subscribe only Bart's address to mlist3.
mlist3.subscribe(bart.preferred_address, MemberRole.moderator)
# There are now 4 memberships, one with Anne two with Bart's user
and
# one with Bart's address.
all_members = list(self._manager.members)
self.assertEqual(len(all_members), 4, all_members)
# Do the absorption.
self._anne.absorb(bart)
# The Bart user has been deleted, leaving only the Anne user in the
# user manager.
all_users = list(self._manager.users)
self.assertEqual(len(all_users), 1)
self.assertEqual(all_users[0], self._anne)
# There are no leftover memberships for user Bart. Anne owns all
the
# memberships.
all_members = list(self._manager.members)
self.assertEqual(len(all_members), 4, all_members)
self.assertEqual(self._anne.memberships.member_count, 4)
memberships = {(member.list_id, member.role): member
for member in self._anne.memberships.members}
# Note that Anne is now both a member and moderator of the test
list.
self.assertEqual(set(memberships), set([
('test.example.com', MemberRole.member),
('test.example.com', MemberRole.moderator),
('test2.example.com', MemberRole.owner),
('test3.example.com', MemberRole.moderator),
]))
# Both of Bart's previous user subscriptions are now transferred to
# the Anne user.
self.assertEqual(
memberships[('test.example.com', MemberRole.moderator)].address,
self._anne.preferred_address)
self.assertEqual(
memberships[('test2.example.com', MemberRole.owner)].address,
self._anne.preferred_address)
# Bart's address was subscribed; it must not have been changed. Of
# course, Anne now controls [email protected].
key = ('test3.example.com', MemberRole.moderator)
self.assertEqual(memberships[key].address.email, '[email protected]')
self.assertEqual(self._manager.get_user('[email protected]'),
self._anne)
The start of the traceback is the statement
# The Bart user has been deleted, leaving only the Anne user in the
# user manager.
all_users = list(self._manager.users)
Versions older than 1.2 do not throw the sqlalchemy.orm.exc.StaleDataError
exception at this point.
If I attempt to fix the test by doing the `self._anne.absorb(bart)` in a
transaction that gets committed on completion, the same exception is thrown
on the commit.
Does anyone have any ideas about this?
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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