Changeset 2992

Timestamp:

05/26/06 13:41:03 (2 years ago)

Author:

lukeplant

Message:

Made negative indexing on QuerySet? instances raise an assertion error (previously
it just returned incorrect results).

Files:

• django/trunk/django/db/models/query.py (modified) (1 diff)
• django/trunk/tests/modeltests/basic/models.py (modified) (1 diff)

django/trunk/django/db/models/query.py

@@ -96 +96 @@
-    def __getitem__(self, k):
-        "Retrieve an item or slice from the set of results."
+        assert (not isinstance(k, slice) and (k >= 0)) \
+            or (isinstance(k, slice) and (k.start is None or k.start >= 0) and (k.stop is None or k.stop >= 0)), \
+            "Negative indexing is not supported."
-        if self._result_cache is None:
-            if isinstance(k, slice):

django/trunk/tests/modeltests/basic/models.py

@@ -284 +284 @@
-AssertionError: Cannot combine queries once a slice has been taken.
-
+# Negative slices are not supported, due to database constraints.
+# (hint: inverting your ordering might do what you need).
+>>> Article.objects.all()[-1]
+Traceback (most recent call last):
+    ...
+AssertionError: Negative indexing is not supported.
+>>> Article.objects.all()[0:-5]
+Traceback (most recent call last):
+    ...
+AssertionError: Negative indexing is not supported.
-
-# An Article instance doesn't have access to the "objects" attribute.