Fixed #28837 -- Fixed test client crash if an exception with more than one arg is raised.

Also removed usage of the problematic pattern elsewhere.

Regression in 6e55e1d88a.

django/db/models/query.py

@@ -4,7 +4,6 @@ The main QuerySet implementation. This provides the public API for the ORM.
 
 import copy
 import operator
-import sys
 import warnings
 from collections import OrderedDict, namedtuple
 from functools import lru_cache
@@ -521,13 +520,12 @@ class QuerySet:
                 params = {k: v() if callable(v) else v for k, v in params.items()}
                 obj = self.create(**params)
             return obj, True
-        except IntegrityError:
+        except IntegrityError as e:
-            exc_info = sys.exc_info()
             try:
                 return self.get(**lookup), False
             except self.model.DoesNotExist:
                 pass
-            raise exc_info[0](exc_info[1]).with_traceback(exc_info[2])
+            raise e
 
     def _extract_model_params(self, defaults, **kwargs):
         """

django/test/client.py

@@ -480,9 +480,9 @@ class Client(RequestFactory):
             # Also make sure that the signalled exception is cleared from
             # the local cache!
             if self.exc_info:
-                exc_info = self.exc_info
+                _, exc_value, _ = self.exc_info
                 self.exc_info = None
-                raise exc_info[0](exc_info[1]).with_traceback(exc_info[2])
+                raise exc_value
 
             # Save the client and request that stimulated the response.
             response.client = self

django/utils/autoreload.py

@@ -245,7 +245,7 @@ def check_errors(fn):
 def raise_last_exception():
     global _exception
     if _exception is not None:
-        raise _exception[0](_exception[1]).with_traceback(_exception[2])
+        raise _exception[1]
 
 
 def ensure_echo_on():

tests/test_client/tests.py

@@ -29,7 +29,7 @@ from django.test import (
 )
 from django.urls import reverse_lazy
 
-from .views import get_view, post_view, trace_view
+from .views import TwoArgException, get_view, post_view, trace_view
 
 
 @override_settings(ROOT_URLCONF='test_client.urls')
@@ -713,6 +713,11 @@ class ClientTest(TestCase):
         with self.assertRaisesMessage(Exception, 'exception message'):
             self.client.get('/nesting_exception_view/')
 
+    def test_response_raises_multi_arg_exception(self):
+        """A request may raise an exception with more than one required arg."""
+        with self.assertRaises(TwoArgException):
+            self.client.get('/two_arg_exception/')
+
     def test_uploading_temp_file(self):
         with tempfile.TemporaryFile() as test_file:
             response = self.client.post('/upload_view/', data={'temp_file': test_file})

tests/test_client/urls.py

@@ -34,6 +34,7 @@ urlpatterns = [
     url(r'^mass_mail_sending_view/$', views.mass_mail_sending_view),
     url(r'^nesting_exception_view/$', views.nesting_exception_view),
     url(r'^django_project_redirect/$', views.django_project_redirect),
+    url(r'^two_arg_exception/$', views.two_arg_exception),
 
     url(r'^accounts/$', RedirectView.as_view(url='login/')),
     url(r'^accounts/no_trailing_slash$', RedirectView.as_view(url='login/')),

tests/test_client/views.py

@@ -331,3 +331,12 @@ def django_project_redirect(request):
 def upload_view(request):
     """Prints keys of request.FILES to the response."""
     return HttpResponse(', '.join(request.FILES))
+
+
+class TwoArgException(Exception):
+    def __init__(self, one, two):
+        pass
+
+
+def two_arg_exception(request):
+    raise TwoArgException('one', 'two')