Commit fd5d0cde authored by Malcolm Tredinnick's avatar Malcolm Tredinnick
Browse files

[1.0.X] Fixed #10432 -- Handle all kinds of iterators in queryset filters. 

Only consumes the iterators once and works with Python 2.3.

Backport of r9986 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9987 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 84b890b6

django/db/models/sql/where.py

+4 −0
Original line number Diff line number Diff line
@@ -43,6 +43,10 @@ class WhereNode(tree.Node): 
            return



        alias, col, field, lookup_type, value = data

        if hasattr(value, '__iter__') and hasattr(value, 'next'):

            # Consume any generators immediately, so that we can determine

            # emptiness and transform any non-empty values correctly.

            value = list(value)

        try:

            if field:

                params = field.get_db_prep_lookup(lookup_type, value)

tests/regressiontests/queries/models.py

+24 −0
Original line number Diff line number Diff line
@@ -1068,6 +1068,19 @@ to set things up correctly internally so that subqueries can continue properly. 
>>> Tag.objects.filter(name__in=()).update(name="foo")

0



Bug #10432 (see also the Python 2.4+ tests for this, below). Testing an empty

"__in" filter with a generator as the value.

>>> def f():

...     return iter([])

>>> n_obj = Note.objects.all()[0]

>>> def g():

...     for i in [n_obj.pk]:

...         yield i

>>> Note.objects.filter(pk__in=f())

[]

>>> list(Note.objects.filter(pk__in=g())) == [n_obj]

True



"""}



# In Python 2.3 and the Python 2.6 beta releases, exceptions raised in __len__
@@ -1101,3 +1114,14 @@ FieldError: Infinite loop caused by ordering. 
[]



"""



# Generator expressions are only in Python 2.4 and later.

if sys.version_info >= (2, 4):

    __test__["API_TESTS"] += """

Using an empty generator expression as the rvalue for an "__in" lookup is legal

(regression for #10432).

>>> Note.objects.filter(pk__in=(x for x in ()))

[]



"""