Avoid printing invalid pointer when api returns 404 (#599)

Author: amw

CHANGELOG.md

@@ -22,6 +22,11 @@ any parts of the framework not mentioned in the documentation should generally b
 * Removed support for Django REST Framework <=3.8.
 * Removed support for Django 2.0.
 
+### Fixed
+
+* Avoid printing invalid pointer when api returns 404
+
+
 ## [2.8.0] - 2019-06-13
 
 This is the last release supporting Python 2.7, Python 3.4, Django Filter 1.1, Django REST Framework <=3.8 and Django 2.0.

example/tests/test_model_viewsets.py

@@ -212,6 +212,19 @@ def test_key_in_post(self):
             get_user_model().objects.get(pk=self.miles.pk).email,
             'miles@trumpet.org')
 
+    def test_404_error_pointer(self):
+        self.client.login(username='miles', password='pw')
+        not_found_url = reverse('user-detail', kwargs={'pk': 12345})
+        errors = {
+            'errors': [
+                {'detail': 'Not found.', 'status': '404'}
+            ]
+        }
+
+        response = self.client.get(not_found_url)
+        assert 404 == response.status_code
+        assert errors == response.json()
+
 
 @pytest.mark.django_db
 def test_patch_allow_field_type(author, author_type_factory, client):

rest_framework_json_api/utils.py

@@ -11,6 +11,7 @@
     ManyToManyDescriptor,
     ReverseManyToOneDescriptor
 )
+from django.http import Http404
 from django.utils import encoding
 from django.utils.module_loading import import_string as import_class_from_dotted_path
 from django.utils.translation import ugettext_lazy as _
@@ -405,6 +406,12 @@ def format_drf_errors(response, context, exc):
             # see if they passed a dictionary to ValidationError manually
             if isinstance(error, dict):
                 errors.append(error)
+            elif isinstance(exc, Http404) and isinstance(error, str):
+                # 404 errors don't have a pointer
+                errors.append({
+                    'detail': error,
+                    'status': encoding.force_text(response.status_code),
+                })
             elif isinstance(error, str):
                 classes = inspect.getmembers(exceptions, inspect.isclass)
                 # DRF sets the `field` to 'detail' for its own exceptions