I'm glad you're still poking because I'm still not seeing anything that would trigger this warning. Here is that exact code in a test case, I can't get it to produce the warning:
from sqlalchemy import *
from sqlalchemy.orm import *
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
class A(Base):
__tablename__ = 'a'
id = Column(Integer, primary_key=True)
_serials = relationship("MetaSerial")
def serials(self):
requiredAmountOfSerials = 10
if requiredAmountOfSerials > len(self._serials):
a_len = len(self._serials)
for a_ctr in range(abs(requiredAmountOfSerials) - a_len):
self._serials.append(MetaSerial())
session.add(self) # MVO? is this needed?
session.flush()
return self._serials
class MetaSerial(Base):
__tablename__ = 'b'
id = Column(Integer, primary_key=True)
a_id = Column(Integer, ForeignKey('a.id'))
e = create_engine("sqlite://", echo=True)
Base.metadata.create_all(e)
session = Session(e)
a1 = A()
# comment out or not, no warning
session.add(a1)
# same
session.flush()
a1.serials()
On Oct 13, 2013, at 12:00 PM, Marc Van Olmen <marcvanol...@gmail.com> wrote:
> I did some more digging today to see If I can pin down the exact reason:
> I tested with a unit test, and reduced the code above to bare minimum and not
> doing references to collections anymore.
>
> def serials(self):
>
> requiredAmountOfSerials = self.quantity
>
> if requiredAmountOfSerials > len(self._serials):
> a_len = len(self._serials)
> for a_ctr in range(abs(requiredAmountOfSerials) - a_len):
> self._serials.append( MetaSerial(value=u''))
>
> Session.add(self) # MVO? is this needed?
> Session.flush()
>
> return self._serials
>
> This above code gives a warning when you try to add for the first time
> something to self._serials collection. (so self._serials has no items)
>
> ----------------------------------------------------------------------
> Traceback (most recent call last):
> File
> "/Users/marcvano/dev/Acclivity/checkout4_env/Checkout/tests/models/serial_test.py",
> line 32, in testMakeRequest
> self.assertEqual(len(op1.serials()), op1.allocated)
> File
> "/Users/marcvano/dev/Acclivity/checkout4_env/Checkout/app/db/request.py",
> line 2161, in serials
> self._serials.append(MetaSerial(value=u''))
> File "build/bdist.macosx-10.6-intel/egg/sqlalchemy/orm/collections.py",
> line 1057, in append
> item = __set(self, item, _sa_initiator)
> File "build/bdist.macosx-10.6-intel/egg/sqlalchemy/orm/collections.py",
> line 1029, in __set
> item = getattr(executor, 'fire_append_event')(item, _sa_initiator)
> File "build/bdist.macosx-10.6-intel/egg/sqlalchemy/orm/collections.py",
> line 729, in fire_append_event
> self._warn_invalidated()
> File "build/bdist.macosx-10.6-intel/egg/sqlalchemy/orm/collections.py",
> line 600, in _warn_invalidated
> util.warn("This collection has been invalidated.")
> File "build/bdist.macosx-10.6-intel/egg/sqlalchemy/util/langhelpers.py",
> line 1036, in warn
> warnings.warn(msg, exc.SAWarning, stacklevel=stacklevel)
> SAWarning: This collection has been invalidated.
>
> Changing above code to:
>
> for a_ctr in range(abs(requiredAmountOfSerials) - a_len):
> a_serial = MetaSerial(value=u'')
> self._serials.append(a_serial)
>
> produces no warnings
>
>
>
>
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