3 files changed, 40 insertions, 18 deletions

diff --git a/rest_framework/generics.py b/rest_framework/generics.py
index afcb8a9f..9ccc7898 100644
--- a/rest_framework/generics.py
+++ b/rest_framework/generics.py
@@ -6,7 +6,7 @@ from __future__ import unicode_literals
 from django.core.exceptions import ImproperlyConfigured, PermissionDenied
 from django.core.paginator import Paginator, InvalidPage
 from django.http import Http404
-from django.shortcuts import get_object_or_404
+from django.shortcuts import get_object_or_404 as _get_object_or_404
 from django.utils.translation import ugettext as _
 from rest_framework import views, mixins, exceptions
 from rest_framework.request import clone_request
@@ -14,6 +14,17 @@ from rest_framework.settings import api_settings
 import warnings
 
 
+def get_object_or_404(queryset, **filter_kwargs):
+    """
+    Same as Django's standard shortcut, but make sure to raise 404
+    if the filter_kwargs don't match the required types.
+    """
+    try:
+        return _get_object_or_404(queryset, **filter_kwargs)
+    except (TypeError, ValueError):
+        raise Http404
+
+
 class GenericAPIView(views.APIView):
     """
     Base class for all other generic views.
diff --git a/rest_framework/relations.py b/rest_framework/relations.py
index c4271e33..41707efc 100644
--- a/rest_framework/relations.py
+++ b/rest_framework/relations.py
@@ -518,8 +518,6 @@ class HyperlinkedIdentityField(Field):
         request = self.context.get('request', None)
         format = self.context.get('format', None)
         view_name = self.view_name or self.parent.opts.view_name
-        lookup_field = getattr(obj, self.lookup_field)
-        kwargs = {self.lookup_field: lookup_field}
 
         if request is None:
             warnings.warn("Using `HyperlinkedIdentityField` without including the "
@@ -539,27 +537,30 @@ class HyperlinkedIdentityField(Field):
         if format and self.format and self.format != format:
             format = self.format
 
+        lookup_field = getattr(obj, self.lookup_field)
+        kwargs = {self.lookup_field: lookup_field}
         try:
             return reverse(view_name, kwargs=kwargs, request=request, format=format)
         except NoReverseMatch:
             pass
 
-        slug = getattr(obj, self.slug_field, None)
-
-        if not slug:
-            raise Exception('Could not resolve URL for field using view name "%s"' % view_name)
-
-        kwargs = {self.slug_url_kwarg: slug}
-        try:
-            return reverse(view_name, kwargs=kwargs, request=request, format=format)
-        except NoReverseMatch:
-            pass
+        if self.pk_url_kwarg != 'pk':
+            # Only try pk lookup if it has been explicitly set.
+            # Otherwise, the default `lookup_field = 'pk'` has us covered.
+            kwargs = {self.pk_url_kwarg: obj.pk}
+            try:
+                return reverse(view_name, kwargs=kwargs, request=request, format=format)
+            except NoReverseMatch:
+                pass
 
-        kwargs = {self.pk_url_kwarg: obj.pk, self.slug_url_kwarg: slug}
-        try:
-            return reverse(view_name, kwargs=kwargs, request=request, format=format)
-        except NoReverseMatch:
-            pass
+        slug = getattr(obj, self.slug_field, None)
+        if slug:
+            # Only use slug lookup if a slug field exists on the model
+            kwargs = {self.slug_url_kwarg: slug}
+            try:
+                return reverse(view_name, kwargs=kwargs, request=request, format=format)
+            except NoReverseMatch:
+                pass
 
         raise Exception('Could not resolve URL for field using view name "%s"' % view_name)
 
diff --git a/rest_framework/tests/generics.py b/rest_framework/tests/generics.py
index f091d0db..37734195 100644
--- a/rest_framework/tests/generics.py
+++ b/rest_framework/tests/generics.py
@@ -279,6 +279,16 @@ class TestInstanceView(TestCase):
         self.assertEqual(response.status_code, status.HTTP_200_OK)
         self.assertEqual(response.data, expected)
 
+    def test_get_instance_view_incorrect_arg(self):
+        """
+        GET requests with an incorrect pk type, should raise 404, not 500.
+        Regression test for #890.
+        """
+        request = factory.get('/a')
+        with self.assertNumQueries(0):
+            response = self.view(request, pk='a').render()
+        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
+
     def test_put_cannot_set_id(self):
         """
         PUT requests to create a new object should not be able to set the id.