diff --git a/django/db/models/sql/where.py b/django/db/models/sql/where.py index a711103485..ec0545ca5b 100644 --- a/django/db/models/sql/where.py +++ b/django/db/models/sql/where.py @@ -47,6 +47,10 @@ class WhereNode(tree.Node): return obj, 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) if hasattr(obj, "process"): try: obj, params = obj.process(lookup_type, value) diff --git a/tests/regressiontests/queries/models.py b/tests/regressiontests/queries/models.py index 727a537e43..ccf06be5f3 100644 --- a/tests/regressiontests/queries/models.py +++ b/tests/regressiontests/queries/models.py @@ -1090,6 +1090,19 @@ 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__ @@ -1140,3 +1153,13 @@ True True """ + +# 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 ())) +[] + +"""