Calling filter() with criterion==None crashes when _aliases_tail exists

[Former user]

I apologize for not following the guidelines but I am not knowledgeable enough to reproduce this in a standalone program.

When using a join on a self-referential table (with aliased=true), a select() call ended in a crash.

I managed to fix it but have no confidence this is the correct fix.

My fix was in sqlalchemy/orm/query.py line 529 (in filter() ).

Existing code:[BR] if self._aliases_tail:[BR] criterion = self._aliases_tail.adapt_clause(criterion)

My fix: change the condition to ensure criterion exists: [BR] if self._aliases_tail and criterion:

[Mike Bayer]

from sqlalchemy import *
from sqlalchemy.orm import *

m = MetaData(create_engine('sqlite://'))
t = Table('foo', m, Column('x', Integer, primary_key=True), Column('y', String(50)))
class Foo(object):
    pass
mapper(Foo, t)

sess = create_session()

q = sess.query(Foo)._from_self()
assert bool(q._aliases_tail)

print q.filter(Foo.y==None).statement

[Former user]

Your code helped me reproduce it. The crash occurs, when the last line is not as in your example but

print q.filter(None).statement

Now, I don't know if it is legal to call filter() with an argument of None, but this was called from other Sqlalchemy code and the decision to send the None could not be traced back to my code. Here is the actual full stack trace:

File '/home/moshe/top/webapp/rma/rma/controllers/list.py', line 216 in list_sources
  c.paginator = paginate.Page(myquery, page_nr = int(c.page_nr))
File '/home/moshe/top/webapp/rma/rma/lib/paginate.py', line 131 in __init__
  self.items = self.collection[self.first_item:self.last_item+1](self.first_item:self.last_item+1)
File '/usr/local/lib/python2.4/site-packages/WebHelpers-0.3.2-py2.4.egg/webhelpers/pagination/orm.py', line 75 in __getitem__
  results = self(limit=limit, offset=offset)
File '/usr/local/lib/python2.4/site-packages/WebHelpers-0.3.2-py2.4.egg/webhelpers/util.py', line 42 in __call__
  return self.fn(*(self.args + args), **d)
File '/home/moshe/top/webapp/rma/sqlalchemy/util.py', line 1176 in func_with_warning
  return func(*args, **kwargs)
File '/home/moshe/top/webapp/rma/sqlalchemy/orm/query.py', line 1336 in select
  return self._build_select(arg, **kwargs).all()
File '/home/moshe/top/webapp/rma/sqlalchemy/orm/query.py', line 1318 in _build_select
  return self.filter(arg)._legacy_select_kwargs(**kwargs)
File '/home/moshe/top/webapp/rma/sqlalchemy/orm/query.py', line 524 in filter
  criterion = self._aliases_tail.adapt_clause(criterion)
File '/home/moshe/top/webapp/rma/sqlalchemy/orm/util.py', line 171 in adapt_clause
  return self.adapter.traverse(clause, clone=True)
File '/home/moshe/top/webapp/rma/sqlalchemy/sql/util.py', line 234 in traverse
  return visitors.ClauseVisitor.traverse(self, obj, clone=True)
File '/home/moshe/top/webapp/rma/sqlalchemy/sql/visitors.py', line 73 in traverse
  return self._cloned_traversal(obj)
File '/home/moshe/top/webapp/rma/sqlalchemy/sql/visitors.py', line 108 in _cloned_traversal
  return self._cloned_traversal_impl(obj, util.Set(stop_on), {}, _clone_toplevel=True)
File '/home/moshe/top/webapp/rma/sqlalchemy/sql/visitors.py', line 115 in _cloned_traversal_impl
  elem = self._clone_element(elem, stop_on, cloned)
File '/home/moshe/top/webapp/rma/sqlalchemy/sql/visitors.py', line 101 in _clone_element
  cloned[elem](elem) = elem._clone()
AttributeError: 'NoneType' object has no attribute '_clone'

[Mike Bayer]

its not valid to call filter() with None in it. Also that WebHelpers library is ancient and is going to need an upgrade very soon, the functions its using are removed in 0.5.

f0be8f1264b596dc838693b2ee381ee98d1d5e4a repairs Query.select().