Made context take priority over context processors.

This is the expected behavior, but given RequestContext's tortuous
implementation, a straightforward use of its API results in the
opposite.

This commits fixes a regression that must have happened at different
points in the multiple templates engine refactor for different features.

django/template/backends/django.py

@@ -45,5 +45,11 @@ def render(self, context=None, request=None):
             if request is None:
                 context = Context(context)
             else:
-                context = RequestContext(request, context)
+                # The following pattern is required to ensure values from
+                # context override those from template context processors.
+                original_context = context
+                context = RequestContext(request)
+                if original_context:
+                    context.push(original_context)
+
         return self.template.render(context)

tests/template_backends/test_django.py

@@ -1,4 +1,7 @@
 from django.template.backends.django import DjangoTemplates
+from django.test import RequestFactory
+
+from template_tests.test_response import test_processor_name
 
 from .test_dummy import TemplateStringsTests
 
@@ -7,3 +10,25 @@ class DjangoTemplatesTests(TemplateStringsTests):
 
     engine_class = DjangoTemplates
     backend_name = 'django'
+
+    def test_context_has_priority_over_template_context_processors(self):
+        # See ticket #23789.
+        engine = DjangoTemplates({
+            'DIRS': [],
+            'APP_DIRS': False,
+            'NAME': 'django',
+            'OPTIONS': {
+                'context_processors': [test_processor_name],
+            },
+        })
+
+        template = engine.from_string('{{ processors }}')
+        request = RequestFactory().get('/')
+
+        # Check that context processors run
+        content = template.render({}, request)
+        self.assertEqual(content, 'yes')
+
+        # Check that context overrides context processors
+        content = template.render({'processors': 'no'}, request)
+        self.assertEqual(content, 'no')