[2.0.x] 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.

Backport of 746caf3ef8 from master

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:
-            exc_info = sys.exc_info()
+        except IntegrityError as e:
             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')