Fixed #22799 -- Made GET and POST on HttpRequest QueryDicts, and FILES a MultiValueDict.

Previously, GET, POST, and FILES on an HttpRequest were created in
the __init__ method as dictionaries. This was not something you would
usually notice causing trouble in production as you'd only see a
WSGIRequest, but in testing using the test client, calling .getlist
on GET, POST, or FILES for a request with no get/post data resulted in
an AttributeError.

Changed GET and POST on an HttpRequest object to be mutable
QueryDicts (mutable because the Django tests, and probably many
third party tests, were expecting it).

django/http/request.py

@@ -49,7 +49,12 @@ class HttpRequest(object):
         # Any variable assignment made here should also happen in
         # `WSGIRequest.__init__()`.
 
-        self.GET, self.POST, self.COOKIES, self.META, self.FILES = {}, {}, {}, {}, {}
+        self.GET = QueryDict(mutable=True)
+        self.POST = QueryDict(mutable=True)
+        self.COOKIES = {}
+        self.META = {}
+        self.FILES = MultiValueDict()
+
         self.path = ''
         self.path_info = ''
         self.method = None

docs/releases/1.8.txt

@@ -220,6 +220,12 @@ Requests and Responses
   instantiated with ``QueryDict()`` instead of ``QueryDict(None)`` or
   ``QueryDict('')``.
 
+* The ``GET`` and ``POST`` attributes of an :class:`~django.http.HttpRequest`
+  object are now :class:`~django.http.QueryDict`\s rather than dictionaries,
+  and the ``FILES`` attribute is now a ``MultiValueDict``.
+  This brings this class into line with the documentation and with
+  ``WSGIRequest``.
+
 Tests
 ^^^^^
 

tests/requests/tests.py

@@ -27,6 +27,13 @@ class RequestsTests(SimpleTestCase):
         self.assertEqual(list(request.COOKIES.keys()), [])
         self.assertEqual(list(request.META.keys()), [])
 
+        # .GET and .POST should be QueryDicts
+        self.assertEqual(request.GET.urlencode(), '')
+        self.assertEqual(request.POST.urlencode(), '')
+
+        # and FILES should be MultiValueDict
+        self.assertEqual(request.FILES.getlist('foo'), [])
+
     def test_httprequest_repr(self):
         request = HttpRequest()
         request.path = '/somepath/'