it has to do with a name conflict between a regular python property
you've configured somewhere, and the name of a mapped attribute or
relation(). The descriptors which SQLAlchemy places on the class
(InstrumentedAttribute) have an "impl" attribute. You'd have to find
what name is conflicting; a pdb or print statement within
attributes.py could reveal the key and class names in play.
(FTR, this kind of error wouldn't occur with SQLA 0.5 which checks for
user-defined descriptors explicitly).
On Aug 18, 2008, at 11:13 AM, Brad Wells wrote:
>
> I receive the following error with SA 0.4.7p1 and the latest 0.4 svn
> revision.
>
> "AttributeError: 'property' object has no attribute 'impl'"
>
> Mappers
> ======
>
> mapper(TransactionType, transaction_types)
>
> transactions_mapper = mapper(Transaction, transactions,
> order_by=transactions.c.date,
> extension=[HistoryMapperExtension(),
> TransactionDateMapperExtension()],
> polymorphic_on=transactions.c.transaction_type_id,
> polymorphic_identity=0,
> exclude_properties=['number', 'address', 'shipping',
> 'handling', 'purchase_order',
> 'contact_note', 'notes', 'valid_until'],
> properties={
> '_voided_at': transactions.c.voided_at,
> '_date': transactions.c.date,
> 'method': relation(PaymentMethodType,
> backref='transactions'),
> 'transaction_type': relation(TransactionType,
> backref='transactions'),
> 'created_by_id': transactions.c.created_by,
> 'updated_by_id': transactions.c.updated_by,
> 'created_by': relation(Contact,
> primaryjoin=transactions.c.created_by==contacts.c.id),
> 'updated_by': relation(Contact,
> primaryjoin=transactions.c.updated_by==contacts.c.id),
> })
>
> mapper(Cost, inherits=transactions_mapper, polymorphic_identity=1,
> properties={
> 'line_items': relation(LineItem, backref='cost',
> cascade='delete')
> })
> mapper(Payment, inherits=transactions_mapper,
> polymorphic_identity=2)
>
> mapper(Receipt, inherits=transactions_mapper,
> polymorphic_identity=4)
> mapper(Adjustment, inherits=transactions_mapper,
> polymorphic_identity=5)
>
> abstract_sales_mapper = mapper(AbstractSale,
> inherits=transactions_mapper,
>
> polymorphic_on=transactions.c.transaction_type_id,
> properties={
> 'number': transactions.c.number,
> 'address': transactions.c.address,
> 'shipping': transactions.c.shipping,
> 'handling': transactions.c.handling,
> 'purchase_order': transactions.c.purchase_order,
> 'contact_note': transactions.c.contact_note,
> 'notes': transactions.c.notes,
> 'payment_terms': relation(PaymentTerm,
> backref='abstract_sales'),
> 'line_items': relation(LineItem, backref='sale',
> cascade='delete', order_by=line_items.c.position)
> })
>
> mapper(Sale, inherits=abstract_sales_mapper,
> polymorphic_identity=3)
>
> mapper(Quote, inherits=abstract_sales_mapper,
> polymorphic_identity=6, properties={
> '_valid_until':
> transactions.c.valid_until
> })
>
>
> The error occurs when performing a query on Transaction ex:
> Transaction.query.get(111)
> where row id 111 is a Quote type. If a query uses the specific class
> type ex: Quote.query.get(111)
> it completes successfully.
>
> I don't know if this is an SA bug or an error in my mappers. Any help
> is appreciated.
>
> -brad
>
>
>
>
> Full Traceback
> ===========
> In [53]: m.Transaction.query.get(112)
> ERROR: An unexpected error occurred while tokenizing input
> The following traceback may be corrupted or invalid
> The error message is: ('EOF in multi-line statement', (141, 0))
>
> ---------------------------------------------------------------------------
> AttributeError Traceback (most recent call
> last)
>
> C:\Documents and Settings\bwells\workspace\ERP GIT TEST\erp\<ipython
> console> in <module>()
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\query.pyc in get(self, ident, **kw
> args)
> 267
> 268 key = self.mapper.identity_key_from_primary_key(ident)
> --> 269 return self._get(key, ident, **kwargs)
> 270
> 271 def load(self, ident, raiseerr=True, **kwargs):
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\query.pyc in _get(self, key, ident
> , refresh_instance, lockmode, only_load_props)
> 1066 try:
> 1067 # call using all() to avoid LIMIT compilation
> complexity
> -> 1068 return q.all()[0]
> 1069 except IndexError:
> 1070 return None
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\query.pyc in all(self)
> 876
> 877 """
> --> 878 return list(self)
> 879
> 880
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\query.pyc in iterate_instances(sel
> f, cursor, *mappers_or_columns, **kwargs)
> 1001 rows = []
> 1002 for row in fetch:
> -> 1003 process[0](context, row, rows)
> 1004 elif single_entity:
> 1005 rows = [process[0](context, row) for row in
> fetch]
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\query.pyc in main(context, row, re
> sult)
> 1579 row = context.row_adapter(row)
> 1580 self.mapper._instance(context, row, result,
> -> 1581 extension=context.extension,
> only_load_props=context.only_load_props, refresh_instance=conte
> xt.refresh_instance
> 1582 )
> 1583 elif context.row_adapter:
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\mapper.pyc in _instance(self, cont
> ext, row, result, polymorphic_from, extension, only_load_props,
> refresh_instance)
> 1366 raise exceptions.AssertionError("No such
> polymorphic_identity %r is defined" % discriminator
> )
> 1367 if mapper is not self:
> -> 1368 return mapper._instance(context, row,
> result=result, polymorphic_from=self)
> 1369
> 1370 # determine identity key
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\mapper.pyc in _instance(self, cont
> ext, row, result, polymorphic_from, extension, only_load_props,
> refresh_instance)
> 1457
> 1458 if 'populate_instance' not in
> extension.methods or extension.populate_instance(self, context, ro
> w, instance, only_load_props=attrs, instancekey=identitykey,
> isnew=isnew) is EXT_CONTINUE:
> -> 1459 self.populate_instance(context, instance,
> row, only_load_props=attrs, instancekey=identityke
> y, isnew=isnew)
> 1460
> 1461 if result is not None and ('append_result' not in
> extension.methods or extension.append_result(self, con
> text, row, instance, result, instancekey=identitykey, isnew=isnew) is
> EXT_CONTINUE):
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\mapper.pyc in populate_instance(se
> lf, selectcontext, instance, row, ispostselect, isnew,
> only_load_props, **flags)
> 1507
> 1508 for (key, populator) in populators:
> -> 1509 selectcontext.exec_with_path(self, key, populator,
> instance, row, ispostselect=ispostselect, isnew=i
> snew, **flags)
> 1510
> 1511 if self.non_primary:
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\query.pyc in exec_with_path(self,
> mapper, propkey, fn, *args, **kwargs)
> 1701 self.path += (mapper.base_mapper, propkey)
> 1702 try:
> -> 1703 return fn(*args, **kwargs)
> 1704 finally:
> 1705 self.path = oldpath
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\strategies.pyc in new_execute(inst
> ance, row, isnew, **flags)
> 84 def new_execute(instance, row, isnew, **flags):
> 85 if isnew:
> ---> 86
> instance._state.expire_attributes([self.key])
> 87 if self._should_log_debug:
> 88 self.logger.debug("Deferring load for %s %s" %
> (mapper, self.key))
>
> C:\Program Files\Python\lib\site-packages\sqlalchemy-0.4.7p1-py2.5.egg
> \sqlalchemy\orm\attributes.pyc in expire_attribute
> s(self, attribute_names)
> 870 self.committed_state.pop(key, None)
> 871 self.expired_attributes.add(key)
> --> 872 if getattr(self.class_,
> key).impl.accepts_scalar_loader:
> 873 self.callables[key] = self
> 874
>
> AttributeError: 'property' object has no attribute 'impl'
> >
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