Fixed #29135 -- Prevented get_object/list_or_404() from hiding AttributeError…

Fixed #29135 -- Prevented get_object/list_or_404() from hiding AttributeError raised by QuerySet filtering.

django/shortcuts.py

@@ -83,14 +83,14 @@ def get_object_or_404(klass, *args, **kwargs):
     one object is found.
     """
     queryset = _get_queryset(klass)
-    try:
-        return queryset.get(*args, **kwargs)
-    except AttributeError:
+    if not hasattr(queryset, 'get'):
         klass__name = klass.__name__ if isinstance(klass, type) else klass.__class__.__name__
         raise ValueError(
             "First argument to get_object_or_404() must be a Model, Manager, "
             "or QuerySet, not '%s'." % klass__name
         )
+    try:
+        return queryset.get(*args, **kwargs)
     except queryset.model.DoesNotExist:
         raise Http404('No %s matches the given query.' % queryset.model._meta.object_name)
 
@@ -104,14 +104,13 @@ def get_list_or_404(klass, *args, **kwargs):
     arguments and keyword arguments are used in the filter() query.
     """
     queryset = _get_queryset(klass)
-    try:
-        obj_list = list(queryset.filter(*args, **kwargs))
-    except AttributeError:
+    if not hasattr(queryset, 'filter'):
         klass__name = klass.__name__ if isinstance(klass, type) else klass.__class__.__name__
         raise ValueError(
             "First argument to get_list_or_404() must be a Model, Manager, or "
             "QuerySet, not '%s'." % klass__name
         )
+    obj_list = list(queryset.filter(*args, **kwargs))
     if not obj_list:
         raise Http404('No %s matches the given query.' % queryset.model._meta.object_name)
     return obj_list

tests/get_object_or_404/models.py

@@ -25,11 +25,17 @@ class ArticleManager(models.Manager):
         return super().get_queryset().filter(authors__name__icontains='sir')
 
 
+class AttributeErrorManager(models.Manager):
+    def get_queryset(self):
+        raise AttributeError('AttributeErrorManager')
+
+
 class Article(models.Model):
     authors = models.ManyToManyField(Author)
     title = models.CharField(max_length=50)
     objects = models.Manager()
     by_a_sir = ArticleManager()
+    attribute_error_objects = AttributeErrorManager()
 
     def __str__(self):
         return self.title

tests/get_object_or_404/tests.py

@@ -94,3 +94,13 @@ class GetObjectOr404Tests(TestCase):
         msg = "First argument to get_list_or_404() must be a Model, Manager, or QuerySet, not 'list'."
         with self.assertRaisesMessage(ValueError, msg):
             get_list_or_404([Article], title__icontains="Run")
+
+    def test_get_object_or_404_queryset_attribute_error(self):
+        """AttributeError raised by QuerySet.get() isn't hidden."""
+        with self.assertRaisesMessage(AttributeError, 'AttributeErrorManager'):
+            get_object_or_404(Article.attribute_error_objects, id=42)
+
+    def test_get_list_or_404_queryset_attribute_error(self):
+        """AttributeError raised by QuerySet.filter() isn't hidden."""
+        with self.assertRaisesMessage(AttributeError, 'AttributeErrorManager'):
+            get_list_or_404(Article.attribute_error_objects, title__icontains='Run')