Merge branch 'master' into schema-alteration

Conflicts: django/db/backends/mysql/introspection.py django/db/backends/oracle/creation.py django/db/backends/postgresql_psycopg2/creation.py django/db/models/base.py django/db/models/loading.py
2013-07-22 19:04:25 +01:00 · 2013-07-22 19:04:25 +01:00 · 03ec3219a0
parent 3a6580e485 29a09b3638
commit 03ec3219a0
231 changed files with 2725 additions and 1373 deletions
--- a/3
+++ b/3
@ -204,6 +204,7 @@ answer newbie questions, and generally made Django that much better:
    Clint Ecker
    Nick Efford <nick@efford.org>
    Marc Egli <frog32@me.com>
+    Matt Deacalion Stevens <matt@dirtymonkey.co.uk>
    eibaan@gmail.com
    David Eklund
    Julia Elman
@ -530,6 +531,7 @@ answer newbie questions, and generally made Django that much better:
    Leo Shklovskii
    jason.sidabras@gmail.com
    Mikołaj Siedlarek <mikolaj.siedlarek@gmail.com>
+    Karol Sikora <elektrrrus@gmail.com>
    Brenton Simpson <http://theillustratedlife.com>
    Jozko Skrablin <jozko.skrablin@gmail.com>
    Ben Slavin <benjamin.slavin@gmail.com>
@ -542,6 +544,7 @@ answer newbie questions, and generally made Django that much better:
    George Song <george@damacy.net>
    sopel
    Leo Soto <leo.soto@gmail.com>
+    Thomas Sorrel
    Wiliam Alves de Souza <wiliamsouza83@gmail.com>
    Don Spaulding <donspauldingii@gmail.com>
    Calvin Spealman <ironfroggy@gmail.com>
--- a/django/conf/global_settings.py
+++ b/django/conf/global_settings.py
@ -184,6 +184,7 @@ EMAIL_PORT = 25
 EMAIL_HOST_USER = ''
 EMAIL_HOST_PASSWORD = ''
 EMAIL_USE_TLS = False
+EMAIL_USE_SSL = False

 # List of strings representing installed apps.
 INSTALLED_APPS = ()
--- a/django/conf/locale/init.py
+++ b/django/conf/locale/init.py
@ -279,7 +279,7 @@ LANG_INFO = {
        'bidi': False,
        'code': 'lt',
        'name': 'Lithuanian',
-        'name_local': 'Lithuanian',
+        'name_local': 'Lietuviškai',
    },
    'lv': {
        'bidi': False,
@ -399,7 +399,7 @@ LANG_INFO = {
        'bidi': False,
        'code': 'sq',
        'name': 'Albanian',
-        'name_local': 'Albanian',
+        'name_local': 'shqip',
    },
    'sr': {
        'bidi': False,
@ -441,7 +441,7 @@ LANG_INFO = {
        'bidi': False,
        'code': 'th',
        'name': 'Thai',
-        'name_local': 'Thai',
+        'name_local': 'ภาษาไทย',
    },
    'tr': {
        'bidi': False,
@ -477,7 +477,7 @@ LANG_INFO = {
        'bidi': False,
        'code': 'vi',
        'name': 'Vietnamese',
-        'name_local': 'Vietnamese',
+        'name_local': 'Tiếng Việt',
    },
    'zh-cn': {
        'bidi': False,
--- a/django/conf/locale/en/LC_MESSAGES/django.po
+++ b/django/conf/locale/en/LC_MESSAGES/django.po
@ -4,7 +4,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Django\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2013-05-25 14:27+0200\n"
+"POT-Creation-Date: 2013-06-11 18:44+0200\n"
 "PO-Revision-Date: 2010-05-13 15:35+0200\n"
 "Last-Translator: Django team\n"
 "Language-Team: English <en@li.org>\n"
@ -699,11 +699,22 @@ msgstr ""
 msgid "Enter a list of values."
 msgstr ""

-#: forms/forms.py:158
+#. Translators: This is the default suffix added to form field labels
+#: forms/forms.py:90
+msgid ":"
+msgstr ""
+
+#: forms/forms.py:159
 #, python-format
 msgid "(Hidden field %(name)s) %(error)s"
 msgstr ""

+#. Translators: If found as last label character, these punctuation
+#. characters will prevent the default label_suffix to be appended to the label
+#: forms/forms.py:525
+msgid ":?.!"
+msgstr ""
+
 #: forms/formsets.py:310
 #, python-format
 msgid "Please submit %d or fewer forms."
--- a/django/contrib/admin/helpers.py
+++ b/django/contrib/admin/helpers.py
@ -266,10 +266,12 @@ class InlineAdminForm(AdminForm):
            yield InlineFieldset(self.formset, self.form, name,
                self.readonly_fields, model_admin=self.model_admin, **options)

-    def has_auto_field(self):
-        if self.form._meta.model._meta.has_auto_field:
+    def needs_explicit_pk_field(self):
+        # Auto fields are editable (oddly), so need to check for auto or non-editable pk
+        if self.form._meta.model._meta.has_auto_field or not self.form._meta.model._meta.pk.editable:
            return True
-        # Also search any parents for an auto field.
+        # Also search any parents for an auto field. (The pk info is propagated to child
+        # models so that does not need to be checked in parents.)
        for parent in self.form._meta.model._meta.get_parent_list():
            if parent._meta.has_auto_field:
                return True
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@ -771,12 +771,10 @@ class ModelAdmin(BaseModelAdmin):
        Returns the preserved filters querystring.
        """

-        # FIXME: We can remove that getattr as soon as #20619 is fixed.
-        match = getattr(request, 'resolver_match', None)
-
+        match = request.resolver_match
        if self.preserve_filters and match:
            opts = self.model._meta
-            current_url = '%s:%s' % (match.namespace, match.url_name)
+            current_url = '%s:%s' % (match.app_name, match.url_name)
            changelist_url = 'admin:%s_%s_changelist' % (opts.app_label, opts.model_name)
            if current_url == changelist_url:
                preserved_filters = request.GET.urlencode()
--- a/django/contrib/admin/sites.py
+++ b/django/contrib/admin/sites.py
@ -439,6 +439,7 @@ class AdminSite(object):
        context = {
            'title': _('%s administration') % capfirst(app_label),
            'app_list': [app_dict],
+            'app_label': app_label,
        }
        context.update(extra_context or {})

--- a/django/contrib/admin/static/admin/js/admin/DateTimeShortcuts.js
+++ b/django/contrib/admin/static/admin/js/admin/DateTimeShortcuts.js
@ -14,6 +14,8 @@ var DateTimeShortcuts = {
    clockDivName: 'clockbox',        // name of clock <div> that gets toggled
    clockLinkName: 'clocklink',      // name of the link that is used to toggle
    shortCutsClass: 'datetimeshortcuts', // class of the clock and cal shortcuts
+    timezoneWarningClass: 'timezonewarning', // class of the warning for timezone mismatch
+    timezoneOffset: 0,
    admin_media_prefix: '',
    init: function() {
        // Get admin_media_prefix by grabbing it off the window object. It's
@ -26,17 +28,77 @@ var DateTimeShortcuts = {
            DateTimeShortcuts.admin_media_prefix = '/missing-admin-media-prefix/';
        }

+        if (window.__admin_utc_offset__ != undefined) {
+            var serverOffset = window.__admin_utc_offset__;
+            var localOffset = new Date().getTimezoneOffset() * -60;
+            DateTimeShortcuts.timezoneOffset = localOffset - serverOffset;
+        }
+
        var inputs = document.getElementsByTagName('input');
        for (i=0; i<inputs.length; i++) {
            var inp = inputs[i];
            if (inp.getAttribute('type') == 'text' && inp.className.match(/vTimeField/)) {
                DateTimeShortcuts.addClock(inp);
+                DateTimeShortcuts.addTimezoneWarning(inp);
            }
            else if (inp.getAttribute('type') == 'text' && inp.className.match(/vDateField/)) {
                DateTimeShortcuts.addCalendar(inp);
+                DateTimeShortcuts.addTimezoneWarning(inp);
            }
        }
    },
+    // Return the current time while accounting for the server timezone.
+    now: function() {
+        if (window.__admin_utc_offset__ != undefined) {
+            var serverOffset = window.__admin_utc_offset__;
+            var localNow = new Date();
+            var localOffset = localNow.getTimezoneOffset() * -60;
+            localNow.setTime(localNow.getTime() + 1000 * (serverOffset - localOffset));
+            return localNow;
+        } else {
+            return new Date();
+        }
+    },
+    // Add a warning when the time zone in the browser and backend do not match.
+    addTimezoneWarning: function(inp) {
+        var $ = django.jQuery;
+        var warningClass = DateTimeShortcuts.timezoneWarningClass;
+        var timezoneOffset = DateTimeShortcuts.timezoneOffset / 3600;
+
+        // Only warn if there is a time zone mismatch.
+        if (!timezoneOffset)
+            return;
+
+        // Check if warning is already there.
+        if ($(inp).siblings('.' + warningClass).length)
+            return;
+
+        var message;
+        if (timezoneOffset > 0) {
+            message = ngettext(
+                'Note: You are %s hour ahead of server time.',
+                'Note: You are %s hours ahead of server time.',
+                timezoneOffset
+            );
+        }
+        else {
+            timezoneOffset *= -1
+            message = ngettext(
+                'Note: You are %s hour behind server time.',
+                'Note: You are %s hours behind server time.',
+                timezoneOffset
+            );
+        }
+        message = interpolate(message, [timezoneOffset]);
+
+        var $warning = $('<span>');
+        $warning.attr('class', warningClass);
+        $warning.text(message);
+
+        $(inp).parent()
+            .append($('<br>'))
+            .append($warning)
+    },
    // Add clock widget to a given field
    addClock: function(inp) {
        var num = DateTimeShortcuts.clockInputs.length;
@ -48,7 +110,7 @@ var DateTimeShortcuts = {
        shortcuts_span.className = DateTimeShortcuts.shortCutsClass;
        inp.parentNode.insertBefore(shortcuts_span, inp.nextSibling);
        var now_link = document.createElement('a');
-        now_link.setAttribute('href', "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", new Date().strftime('" + get_format('TIME_INPUT_FORMATS')[0] + "'));");
+        now_link.setAttribute('href', "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", -1);");
        now_link.appendChild(document.createTextNode(gettext('Now')));
        var clock_link = document.createElement('a');
        clock_link.setAttribute('href', 'javascript:DateTimeShortcuts.openClock(' + num + ');');
@ -84,11 +146,10 @@ var DateTimeShortcuts = {
        quickElement('h2', clock_box, gettext('Choose a time'));
        var time_list = quickElement('ul', clock_box, '');
        time_list.className = 'timelist';
-        var time_format = get_format('TIME_INPUT_FORMATS')[0];
-        quickElement("a", quickElement("li", time_list, ""), gettext("Now"), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", new Date().strftime('" + time_format + "'));");
-        quickElement("a", quickElement("li", time_list, ""), gettext("Midnight"), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", new Date(1970,1,1,0,0,0,0).strftime('" + time_format + "'));");
-        quickElement("a", quickElement("li", time_list, ""), gettext("6 a.m."), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", new Date(1970,1,1,6,0,0,0).strftime('" + time_format + "'));");
-        quickElement("a", quickElement("li", time_list, ""), gettext("Noon"), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", new Date(1970,1,1,12,0,0,0).strftime('" + time_format + "'));");
+        quickElement("a", quickElement("li", time_list, ""), gettext("Now"), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", -1);");
+        quickElement("a", quickElement("li", time_list, ""), gettext("Midnight"), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", 0);");
+        quickElement("a", quickElement("li", time_list, ""), gettext("6 a.m."), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", 6);");
+        quickElement("a", quickElement("li", time_list, ""), gettext("Noon"), "href", "javascript:DateTimeShortcuts.handleClockQuicklink(" + num + ", 12);");

        var cancel_p = quickElement('p', clock_box, '');
        cancel_p.className = 'calendar-cancel';
@ -128,7 +189,14 @@ var DateTimeShortcuts = {
       removeEvent(document, 'click', DateTimeShortcuts.dismissClockFunc[num]);
    },
    handleClockQuicklink: function(num, val) {
-       DateTimeShortcuts.clockInputs[num].value = val;
+       var d;
+       if (val == -1) {
+           d = DateTimeShortcuts.now();
+       }
+       else {
+           d = new Date(1970, 1, 1, val, 0, 0, 0)
+       }
+       DateTimeShortcuts.clockInputs[num].value = d.strftime(get_format('TIME_INPUT_FORMATS')[0]);
       DateTimeShortcuts.clockInputs[num].focus();
       DateTimeShortcuts.dismissClock(num);
    },
@ -258,7 +326,7 @@ var DateTimeShortcuts = {
        DateTimeShortcuts.calendars[num].drawNextMonth();
    },
    handleCalendarCallback: function(num) {
-        format = get_format('DATE_INPUT_FORMATS')[0];
+        var format = get_format('DATE_INPUT_FORMATS')[0];
        // the format needs to be escaped a little
        format = format.replace('\\', '\\\\');
        format = format.replace('\r', '\\r');
@ -276,7 +344,7 @@ var DateTimeShortcuts = {
               ").style.display='none';}"].join('');
    },
    handleCalendarQuickLink: function(num, offset) {
-       var d = new Date();
+       var d = DateTimeShortcuts.now();
       d.setDate(d.getDate() + offset)
       DateTimeShortcuts.calendarInputs[num].value = d.strftime(get_format('DATE_INPUT_FORMATS')[0]);
       DateTimeShortcuts.calendarInputs[num].focus();
--- a/django/contrib/admin/static/admin/js/admin/RelatedObjectLookups.js
+++ b/django/contrib/admin/static/admin/js/admin/RelatedObjectLookups.js
@ -55,7 +55,7 @@ function dismissRelatedLookupPopup(win, chosenId) {
 function showAddAnotherPopup(triggeringLink) {
    var name = triggeringLink.id.replace(/^add_/, '');
    name = id_to_windowname(name);
-    href = triggeringLink.href
+    var href = triggeringLink.href;
    if (href.indexOf('?') == -1) {
        href += '?_popup=1';
    } else {
@ -73,10 +73,11 @@ function dismissAddAnotherPopup(win, newId, newRepr) {
    newRepr = html_unescape(newRepr);
    var name = windowname_to_id(win.name);
    var elem = document.getElementById(name);
+    var o;
    if (elem) {
        var elemName = elem.nodeName.toUpperCase();
        if (elemName == 'SELECT') {
-            var o = new Option(newRepr, newId);
+            o = new Option(newRepr, newId);
            elem.options[elem.options.length] = o;
            o.selected = true;
        } else if (elemName == 'INPUT') {
@ -88,8 +89,7 @@ function dismissAddAnotherPopup(win, newId, newRepr) {
        }
    } else {
        var toId = name + "_to";
-        elem = document.getElementById(toId);
-        var o = new Option(newRepr, newId);
+        o = new Option(newRepr, newId);
        SelectBox.add_to_cache(toId, o);
        SelectBox.redisplay(toId);
    }
--- a/django/contrib/admin/templates/admin/app_index.html
+++ b/django/contrib/admin/templates/admin/app_index.html
@ -1,6 +1,8 @@
 {% extends "admin/index.html" %}
 {% load i18n %}

+{% block bodyclass %}app-{{ app_label }} {{ block.super }}{% endblock %}
+
 {% if not is_popup %}
 {% block breadcrumbs %}
 <div class="breadcrumbs">
--- a/django/contrib/admin/templates/admin/base.html
+++ b/django/contrib/admin/templates/admin/base.html
@ -7,6 +7,7 @@
 <!--[if lte IE 7]><link rel="stylesheet" type="text/css" href="{% block stylesheet_ie %}{% static "admin/css/ie.css" %}{% endblock %}" /><![endif]-->
 {% if LANGUAGE_BIDI %}<link rel="stylesheet" type="text/css" href="{% block stylesheet_rtl %}{% static "admin/css/rtl.css" %}{% endblock %}" />{% endif %}
 <script type="text/javascript">window.__admin_media_prefix__ = "{% filter escapejs %}{% static "admin/" %}{% endfilter %}";</script>
+<script type="text/javascript">window.__admin_utc_offset__ = "{% filter escapejs %}{% now "Z" %}{% endfilter %}";</script>
 {% block extrahead %}{% endblock %}
 {% block blockbots %}<meta name="robots" content="NONE,NOARCHIVE" />{% endblock %}
 </head>
--- a/django/contrib/admin/templates/admin/change_form.html
+++ b/django/contrib/admin/templates/admin/change_form.html
@ -10,7 +10,7 @@

 {% block coltype %}colM{% endblock %}

-{% block bodyclass %}{{ opts.app_label }}-{{ opts.object_name.lower }} change-form{% endblock %}
+{% block bodyclass %}app-{{ opts.app_label }} model-{{ opts.object_name.lower }} change-form{% endblock %}

 {% if not is_popup %}
 {% block breadcrumbs %}
--- a/django/contrib/admin/templates/admin/change_list.html
+++ b/django/contrib/admin/templates/admin/change_list.html
@ -32,7 +32,7 @@
 {% endif %}{% endif %}
 {% endblock %}

-{% block bodyclass %}change-list{% endblock %}
+{% block bodyclass %}app-{{ opts.app_label }} model-{{ opts.object_name.lower }} change-list{% endblock %}

 {% if not is_popup %}
 {% block breadcrumbs %}
--- a/django/contrib/admin/templates/admin/delete_confirmation.html
+++ b/django/contrib/admin/templates/admin/delete_confirmation.html
@ -1,6 +1,8 @@
 {% extends "admin/base_site.html" %}
 {% load i18n admin_urls %}

+{% block bodyclass %}app-{{ opts.app_label }} model-{{ opts.object_name.lower }} delete-confirmation{% endblock %}
+
 {% block breadcrumbs %}
 <div class="breadcrumbs">
 <a href="{% url 'admin:index' %}">{% trans 'Home' %}</a>
--- a/django/contrib/admin/templates/admin/delete_selected_confirmation.html
+++ b/django/contrib/admin/templates/admin/delete_selected_confirmation.html
@ -1,6 +1,8 @@
 {% extends "admin/base_site.html" %}
 {% load i18n l10n admin_urls %}

+{% block bodyclass %}app-{{ opts.app_label }} model-{{ opts.object_name.lower }} delete-confirmation delete-selected-confirmation{% endblock %}
+
 {% block breadcrumbs %}
 <div class="breadcrumbs">
 <a href="{% url 'admin:index' %}">{% trans 'Home' %}</a>
--- a/django/contrib/admin/templates/admin/edit_inline/stacked.html
+++ b/django/contrib/admin/templates/admin/edit_inline/stacked.html
@ -13,7 +13,7 @@
  {% for fieldset in inline_admin_form %}
    {% include "admin/includes/fieldset.html" %}
  {% endfor %}
-  {% if inline_admin_form.has_auto_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
+  {% if inline_admin_form.needs_explicit_pk_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
  {{ inline_admin_form.fk_field.field }}
 </div>{% endfor %}
 </div>
--- a/django/contrib/admin/templates/admin/edit_inline/tabular.html
+++ b/django/contrib/admin/templates/admin/edit_inline/tabular.html
@ -29,7 +29,7 @@
          {% if inline_admin_form.original %} {{ inline_admin_form.original }}{% endif %}
          {% if inline_admin_form.show_url %}<a href="{% url 'admin:view_on_site' inline_admin_form.original_content_type_id inline_admin_form.original.pk %}">{% trans "View on site" %}</a>{% endif %}
            </p>{% endif %}
-          {% if inline_admin_form.has_auto_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
+          {% if inline_admin_form.needs_explicit_pk_field %}{{ inline_admin_form.pk_field.field }}{% endif %}
          {{ inline_admin_form.fk_field.field }}
          {% spaceless %}
          {% for fieldset in inline_admin_form %}
--- a/django/contrib/admin/templatetags/admin_urls.py
+++ b/django/contrib/admin/templatetags/admin_urls.py
@ -38,7 +38,7 @@ def add_preserved_filters(context, url, popup=False):
        except Resolver404:
            pass
        else:
-            current_url = '%s:%s' % (match.namespace, match.url_name)
+            current_url = '%s:%s' % (match.app_name, match.url_name)
            changelist_url = 'admin:%s_%s_changelist' % (opts.app_label, opts.model_name)
            if changelist_url == current_url and '_changelist_filters' in preserved_filters:
                preserved_filters = dict(parse_qsl(preserved_filters['_changelist_filters']))
--- a/django/contrib/auth/admin.py
+++ b/django/contrib/auth/admin.py
@ -70,10 +70,7 @@ class UserAdmin(admin.ModelAdmin):
        """
        defaults = {}
        if obj is None:
-            defaults.update({
-                'form': self.add_form,
-                'fields': admin.util.flatten_fieldsets(self.add_fieldsets),
-            })
+            defaults['form'] = self.add_form
        defaults.update(kwargs)
        return super(UserAdmin, self).get_form(request, obj, **defaults)

--- a/django/contrib/auth/backends.py
+++ b/django/contrib/auth/backends.py
@ -5,7 +5,7 @@ from django.contrib.auth.models import Permission

 class ModelBackend(object):
    """
-    Authenticates against django.contrib.auth.models.User.
+    Authenticates against settings.AUTH_USER_MODEL.
    """

    def authenticate(self, username=None, password=None, **kwargs):
--- a/django/contrib/auth/hashers.py
+++ b/django/contrib/auth/hashers.py
@ -22,6 +22,7 @@ UNUSABLE_PASSWORD_SUFFIX_LENGTH = 40  # number of random chars to add after UNUS
 HASHERS = None  # lazily loaded from PASSWORD_HASHERS
 PREFERRED_HASHER = None  # defaults to first item in PASSWORD_HASHERS

+
@receiver(setting_changed)
 def reset_hashers(**kwargs):
    if kwargs['setting'] == 'PASSWORD_HASHERS':
@ -34,7 +35,7 @@ def is_password_usable(encoded):
    if encoded is None or encoded.startswith(UNUSABLE_PASSWORD_PREFIX):
        return False
    try:
-        hasher = identify_hasher(encoded)
+        identify_hasher(encoded)
    except ValueError:
        return False
    return True
@ -48,7 +49,7 @@ def check_password(password, encoded, setter=None, preferred='default'):
    If setter is specified, it'll be called when you need to
    regenerate the password.
    """
-    if not is_password_usable(encoded):
+    if password is None or not is_password_usable(encoded):
        return False

    preferred = get_hasher(preferred)
--- a/django/contrib/auth/tests/test_hashers.py
+++ b/django/contrib/auth/tests/test_hashers.py
@ -187,6 +187,13 @@ class TestUtilsHashPass(unittest.TestCase):
        # This might fail one day due to a hash collision.
        self.assertNotEqual(encoded, make_password(None), "Random password collision?")

+    def test_unspecified_password(self):
+        """
+        Makes sure specifying no plain password with a valid encoded password
+        returns `False`.
+        """
+        self.assertFalse(check_password(None, make_password('lètmein')))
+
    def test_bad_algorithm(self):
        with self.assertRaises(ValueError):
            make_password('lètmein', hasher='lolcat')
--- a/django/contrib/contenttypes/generic.py
+++ b/django/contrib/contenttypes/generic.py
@ -66,7 +66,7 @@ class GenericForeignKey(six.with_metaclass(RenameGenericForeignKeyMethods)):
        if obj is not None:
            return ContentType.objects.db_manager(obj._state.db).get_for_model(
                obj, for_concrete_model=self.for_concrete_model)
-        elif id:
+        elif id is not None:
            return ContentType.objects.db_manager(using).get_for_id(id)
        else:
            # This should never happen. I love comments like this, don't you?
@ -130,7 +130,7 @@ class GenericForeignKey(six.with_metaclass(RenameGenericForeignKeyMethods)):
            # performance when dealing with GFKs in loops and such.
            f = self.model._meta.get_field(self.ct_field)
            ct_id = getattr(instance, f.get_attname(), None)
-            if ct_id:
+            if ct_id is not None:
                ct = self.get_content_type(id=ct_id, using=instance._state.db)
                try:
                    rel_obj = ct.get_object_for_this_type(pk=getattr(instance, self.fk_field))
--- a/django/contrib/gis/db/backends/oracle/operations.py
+++ b/django/contrib/gis/db/backends/oracle/operations.py
@ -78,7 +78,7 @@ class OracleOperations(DatabaseOperations, BaseSpatialOperations):

    name = 'oracle'
    oracle = True
-    valid_aggregates = dict([(a, None) for a in ('Union', 'Extent')])
+    valid_aggregates = {'Union', 'Extent'}

    Adapter = OracleSpatialAdapter
    Adaptor = Adapter # Backwards-compatibility alias.
--- a/django/contrib/gis/db/backends/postgis/operations.py
+++ b/django/contrib/gis/db/backends/postgis/operations.py
@ -56,6 +56,7 @@ class PostGISSphereDistance(PostGISDistance):
 class PostGISRelate(PostGISFunctionParam):
    "For PostGIS Relate(<geom>, <pattern>) calls."
    pattern_regex = re.compile(r'^[012TF\*]{9}$')
+
    def __init__(self, prefix, pattern):
        if not self.pattern_regex.match(pattern):
            raise ValueError('Invalid intersection matrix pattern "%s".' % pattern)
@ -68,8 +69,7 @@ class PostGISOperations(DatabaseOperations, BaseSpatialOperations):
    postgis = True
    geom_func_prefix = 'ST_'
    version_regex = re.compile(r'^(?P<major>\d)\.(?P<minor1>\d)\.(?P<minor2>\d+)')
-    valid_aggregates = dict([(k, None) for k in
-                             ('Collect', 'Extent', 'Extent3D', 'MakeLine', 'Union')])
+    valid_aggregates = {'Collect', 'Extent', 'Extent3D', 'MakeLine', 'Union'}

    Adapter = PostGISAdapter
    Adaptor = Adapter # Backwards-compatibility alias.
--- a/django/contrib/gis/db/backends/spatialite/operations.py
+++ b/django/contrib/gis/db/backends/spatialite/operations.py
@ -56,7 +56,7 @@ class SpatiaLiteOperations(DatabaseOperations, BaseSpatialOperations):
    name = 'spatialite'
    spatialite = True
    version_regex = re.compile(r'^(?P<major>\d)\.(?P<minor1>\d)\.(?P<minor2>\d+)')
-    valid_aggregates = dict([(k, None) for k in ('Extent', 'Union')])
+    valid_aggregates = {'Extent', 'Union'}

    Adapter = SpatiaLiteAdapter
    Adaptor = Adapter # Backwards-compatibility alias.
@ -169,6 +169,7 @@ class SpatiaLiteOperations(DatabaseOperations, BaseSpatialOperations):
        Checks if the given aggregate name is supported (that is, if it's
        in `self.valid_aggregates`).
        """
+        super(SpatiaLiteOperations, self).check_aggregate_support(aggregate)
        agg_name = aggregate.__class__.__name__
        return agg_name in self.valid_aggregates

--- a/django/contrib/gis/db/models/query.py
+++ b/django/contrib/gis/db/models/query.py
@ -140,7 +140,7 @@ class GeoQuerySet(QuerySet):
        Returns a GeoJSON representation of the geomtry field in a `geojson`
        attribute on each element of the GeoQuerySet.

-        The `crs` and `bbox` keywords may be set to True if the users wants
+        The `crs` and `bbox` keywords may be set to True if the user wants
        the coordinate reference system and the bounding box to be included
        in the GeoJSON representation of the geometry.
        """
--- a/django/contrib/gis/gdal/geometries.py
+++ b/django/contrib/gis/gdal/geometries.py
@ -198,14 +198,6 @@ class OGRGeometry(GDALBase):

    def _get_coord_dim(self):
        "Returns the coordinate dimension of the Geometry."
-        if isinstance(self, GeometryCollection) and GDAL_VERSION < (1, 5, 2):
-            # On GDAL versions prior to 1.5.2, there exists a bug in which
-            # the coordinate dimension of geometry collections is always 2:
-            #   http://trac.osgeo.org/gdal/ticket/2334
-            # Here we workaround by returning the coordinate dimension of the
-            # first geometry in the collection instead.
-            if len(self):
-                return capi.get_coord_dim(capi.get_geom_ref(self.ptr, 0))
        return capi.get_coord_dim(self.ptr)

    def _set_coord_dim(self, dim):
--- a/django/contrib/gis/management/commands/ogrinspect.py
+++ b/django/contrib/gis/management/commands/ogrinspect.py
@ -53,7 +53,7 @@ class Command(LabelCommand):
        make_option('--multi-geom', action='store_true', dest='multi_geom', default=False,
                    help='Treat the geometry in the data source as a geometry collection.'),
        make_option('--name-field', dest='name_field',
-                    help='Specifies a field name to return for the `__unicode__` function.'),
+                    help='Specifies a field name to return for the `__unicode__`/`__str__` function.'),
        make_option('--no-imports', action='store_false', dest='imports', default=True,
                    help='Do not include `from django.contrib.gis.db import models` '
                    'statement.'),
--- a/django/contrib/gis/maps/google/gmap.py
+++ b/django/contrib/gis/maps/google/gmap.py
@ -134,7 +134,8 @@ class GoogleMap(object):
    @property
    def scripts(self):
        "Returns all <script></script> tags required with Google Maps JavaScript."
-        return format_html('%s\n  <script type="text/javascript">\n//<![CDATA[\n%s//]]>\n  </script>', self.api_script, mark_safe(self.js))
+        return format_html('{0}\n  <script type="text/javascript">\n//<![CDATA[\n{1}//]]>\n  </script>',
+                           self.api_script, mark_safe(self.js))

    @property
    def style(self):
--- a/django/contrib/gis/tests/init.py
+++ b/django/contrib/gis/tests/init.py
@ -1,30 +0,0 @@
-def geo_apps():
-    """
-    Returns a list of GeoDjango test applications that reside in
-    `django.contrib.gis.tests` that can be used with the current
-    database and the spatial libraries that are installed.
-    """
-    from django.db import connection
-    from django.contrib.gis.geos import GEOS_PREPARE
-    from django.contrib.gis.gdal import HAS_GDAL
-
-    apps = ['geoapp', 'relatedapp']
-
-    # No distance queries on MySQL.
-    if not connection.ops.mysql:
-        apps.append('distapp')
-
-    # Test geography support with PostGIS 1.5+.
-    if connection.ops.postgis and connection.ops.geography:
-        apps.append('geogapp')
-
-    # The following GeoDjango test apps depend on GDAL support.
-    if HAS_GDAL:
-        # Geographic admin, LayerMapping, and ogrinspect test apps
-        # all require GDAL.
-        apps.extend(['geoadmin', 'layermap', 'inspectapp'])
-
-        # 3D apps use LayerMapping, which uses GDAL and require GEOS 3.1+.
-        if connection.ops.postgis and GEOS_PREPARE:
-            apps.append('geo3d')
-    return [('django.contrib.gis.tests', app) for app in apps]
--- a/django/contrib/gis/tests/geoadmin/tests.py
+++ b/django/contrib/gis/tests/geoadmin/tests.py
@ -2,9 +2,10 @@ from __future__ import absolute_import

 from unittest import skipUnless

-from django.test import TestCase
 from django.contrib.gis.geos import HAS_GEOS
 from django.contrib.gis.tests.utils import HAS_SPATIAL_DB
+from django.test import TestCase
+from django.test.utils import override_settings

 if HAS_GEOS and HAS_SPATIAL_DB:
    from django.contrib.gis import admin
@ -12,6 +13,8 @@ if HAS_GEOS and HAS_SPATIAL_DB:

    from .models import City

+GOOGLE_MAPS_API_KEY = 'XXXX'
+

@skipUnless(HAS_GEOS and HAS_SPATIAL_DB, "Geos and spatial db are required.")
 class GeoAdminTest(TestCase):
@ -39,7 +42,9 @@ class GeoAdminTest(TestCase):
            result)

    def test_olwidget_has_changed(self):
-        """ Check that changes are accurately noticed by OpenLayersWidget. """
+        """
+        Check that changes are accurately noticed by OpenLayersWidget.
+        """
        geoadmin = admin.site._registry[City]
        form = geoadmin.get_changelist_form(None)()
        has_changed = form.fields['point']._has_changed
@ -55,3 +60,15 @@ class GeoAdminTest(TestCase):
        self.assertFalse(has_changed(initial, data_same))
        self.assertFalse(has_changed(initial, data_almost_same))
        self.assertTrue(has_changed(initial, data_changed))
+
+    @override_settings(GOOGLE_MAPS_API_KEY=GOOGLE_MAPS_API_KEY)
+    def test_google_map_scripts(self):
+        """
+        Testing GoogleMap.scripts() output. See #20773.
+        """
+        from django.contrib.gis.maps.google.gmap import GoogleMap
+
+        google_map = GoogleMap()
+        scripts = google_map.scripts
+        self.assertIn(GOOGLE_MAPS_API_KEY, scripts)
+        self.assertIn("new GMap2", scripts)
--- a/django/contrib/gis/tests/geoapp/test_sitemaps.py
+++ b/django/contrib/gis/tests/geoapp/test_sitemaps.py
@ -3,6 +3,7 @@ from __future__ import absolute_import
 from io import BytesIO
 from unittest import skipUnless
 from xml.dom import minidom
+import os
 import zipfile

 from django.conf import settings
@ -10,6 +11,7 @@ from django.contrib.gis.geos import HAS_GEOS
 from django.contrib.gis.tests.utils import HAS_SPATIAL_DB
 from django.contrib.sites.models import Site
 from django.test import TestCase
+from django.utils._os import upath

 if HAS_GEOS:
    from .models import City, Country
@ -37,7 +39,11 @@ class GeoSitemapTest(TestCase):
    def test_geositemap_index(self):
        "Tests geographic sitemap index."
        # Getting the geo index.
-        doc = minidom.parseString(self.client.get('/sitemap.xml').content)
+        from django.contrib import sitemaps
+        template_dirs = settings.TEMPLATE_DIRS + (
+            os.path.join(os.path.dirname(upath(sitemaps.__file__)), 'templates'),)
+        with self.settings(TEMPLATE_DIRS=template_dirs):
+            doc = minidom.parseString(self.client.get('/sitemap.xml').content)
        index = doc.firstChild
        self.assertEqual(index.getAttribute('xmlns'), 'http://www.sitemaps.org/schemas/sitemap/0.9')
        self.assertEqual(3, len(index.getElementsByTagName('sitemap')))
--- a/django/contrib/gis/tests/geoapp/tests.py
+++ b/django/contrib/gis/tests/geoapp/tests.py
@ -8,7 +8,7 @@ from django.db import connection
 from django.contrib.gis import gdal
 from django.contrib.gis.geos import HAS_GEOS
 from django.contrib.gis.tests.utils import (
-    no_mysql, no_oracle, no_spatialite,
+    HAS_SPATIAL_DB, no_mysql, no_oracle, no_spatialite,
    mysql, oracle, postgis, spatialite)
 from django.test import TestCase
 from django.utils import six
@ -28,7 +28,7 @@ def postgis_bug_version():
    return spatial_version and (2, 0, 0) <= spatial_version <= (2, 0, 1)


-@skipUnless(HAS_GEOS and postgis, "Geos and postgis are required.")
+@skipUnless(HAS_GEOS and HAS_SPATIAL_DB, "Geos and spatial db are required.")
 class GeoModelTest(TestCase):

    def test_fixtures(self):
@ -203,7 +203,7 @@ class GeoModelTest(TestCase):
        self.assertTrue(isinstance(cities2[0].point, Point))


-@skipUnless(HAS_GEOS and postgis, "Geos and postgis are required.")
+@skipUnless(HAS_GEOS and HAS_SPATIAL_DB, "Geos and spatial db are required.")
 class GeoLookupTest(TestCase):

    @no_mysql
@ -389,7 +389,7 @@ class GeoLookupTest(TestCase):
            self.assertEqual('Lawrence', City.objects.get(point__relate=(ks.poly, intersects_mask)).name)


-@skipUnless(HAS_GEOS and postgis, "Geos and postgis are required.")
+@skipUnless(HAS_GEOS and HAS_SPATIAL_DB, "Geos and spatial db are required.")
 class GeoQuerySetTest(TestCase):
    # Please keep the tests in GeoQuerySet method's alphabetic order

@ -433,6 +433,13 @@ class GeoQuerySetTest(TestCase):
                self.assertEqual(c.mpoly.sym_difference(geom), c.sym_difference)
                self.assertEqual(c.mpoly.union(geom), c.union)

+    @skipUnless(getattr(connection.ops, 'envelope', False), 'Database does not support envelope operation')
+    def test_envelope(self):
+        "Testing the `envelope` GeoQuerySet method."
+        countries = Country.objects.all().envelope()
+        for country in countries:
+            self.assertIsInstance(country.envelope, Polygon)
+
    @no_mysql
    @no_spatialite # SpatiaLite does not have an Extent function
    def test_extent(self):
--- a/django/contrib/gis/tests/test_spatialrefsys.py
+++ b/django/contrib/gis/tests/test_spatialrefsys.py
@ -23,7 +23,7 @@ test_srs = ({'srid' : 4326,
             'auth_srid' : 32140,
             'srtext' : 'PROJCS["NAD83 / Texas South Central",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS 1980"',
             'proj4_re' : r'\+proj=lcc \+lat_1=30.28333333333333 \+lat_2=28.38333333333333 \+lat_0=27.83333333333333 '
-                          r'\+lon_0=-99 \+x_0=600000 \+y_0=4000000 \+ellps=GRS80 '
+                          r'\+lon_0=-99 \+x_0=600000 \+y_0=4000000 (\+ellps=GRS80 )?'
                          r'(\+datum=NAD83 |\+towgs84=0,0,0,0,0,0,0)?\+units=m \+no_defs ',
             'spheroid' : 'GRS 1980', 'name' : 'NAD83 / Texas South Central',
             'geographic' : False, 'projected' : True, 'spatialite' : False,
--- a/django/contrib/gis/utils/ogrinspect.py
+++ b/django/contrib/gis/utils/ogrinspect.py
@ -89,7 +89,7 @@ def ogrinspect(*args, **kwargs):
     `multi_geom` => Boolean (default: False) - specify as multigeometry.

     `name_field` => String - specifies a field name to return for the
-       `__unicode__` function (which will be generated if specified).
+       `__unicode__`/`__str__` function (which will be generated if specified).

     `imports` => Boolean (default: True) - set to False to omit the
       `from django.contrib.gis.db import models` code from the
@ -221,4 +221,5 @@ def _ogrinspect(data_source, model_name, geom_name='geom', layer_key=0, srid=Non

    if name_field:
        yield ''
-        yield '    def __str__(self): return self.%s' % name_field
+        yield '    def __%s__(self): return self.%s' % (
+            'str' if six.PY3 else 'unicode', name_field)
--- a/django/contrib/syndication/views.py
+++ b/django/contrib/syndication/views.py
@ -43,9 +43,9 @@ class Feed(object):
            raise Http404('Feed object does not exist.')
        feedgen = self.get_feed(obj, request)
        response = HttpResponse(content_type=feedgen.mime_type)
-        if hasattr(self, 'item_pubdate'):
-            # if item_pubdate is defined for the feed, set header so as
-            # ConditionalGetMiddleware is able to send 304 NOT MODIFIED
+        if hasattr(self, 'item_pubdate') or hasattr(self, 'item_updateddate'):
+            # if item_pubdate or item_updateddate is defined for the feed, set
+            # header so as ConditionalGetMiddleware is able to send 304 NOT MODIFIED
            response['Last-Modified'] = http_date(
                timegm(feedgen.latest_post_date().utctimetuple()))
        feedgen.write(response, 'utf-8')
@ -191,6 +191,11 @@ class Feed(object):
                ltz = tzinfo.LocalTimezone(pubdate)
                pubdate = pubdate.replace(tzinfo=ltz)

+            updateddate = self.__get_dynamic_attr('item_updateddate', item)
+            if updateddate and is_naive(updateddate):
+                ltz = tzinfo.LocalTimezone(updateddate)
+                updateddate = updateddate.replace(tzinfo=ltz)
+
            feed.add_item(
                title = title,
                link = link,
@ -200,6 +205,7 @@ class Feed(object):
                    'item_guid_is_permalink', item),
                enclosure = enc,
                pubdate = pubdate,
+                updateddate = updateddate,
                author_name = author_name,
                author_email = author_email,
                author_link = author_link,
--- a/django/core/cache/backends/locmem.py
+++ b/django/core/cache/backends/locmem.py
@ -9,16 +9,17 @@ except ImportError:
 from django.core.cache.backends.base import BaseCache, DEFAULT_TIMEOUT
 from django.utils.synch import RWLock

+
 # Global in-memory store of cache data. Keyed by name, to provide
 # multiple named local memory caches.
 _caches = {}
 _expire_info = {}
 _locks = {}

+
 class LocMemCache(BaseCache):
    def __init__(self, name, params):
        BaseCache.__init__(self, params)
-        global _caches, _expire_info, _locks
        self._cache = _caches.setdefault(name, {})
        self._expire_info = _expire_info.setdefault(name, {})
        self._lock = _locks.setdefault(name, RWLock())
@ -26,28 +27,31 @@ class LocMemCache(BaseCache):
    def add(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
        key = self.make_key(key, version=version)
        self.validate_key(key)
+        try:
+            pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
+        except pickle.PickleError:
+            return False
        with self._lock.writer():
            exp = self._expire_info.get(key)
            if exp is None or exp <= time.time():
-                try:
-                    pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
-                    self._set(key, pickled, timeout)
-                    return True
-                except pickle.PickleError:
-                    pass
+                self._set(key, pickled, timeout)
+                return True
            return False

    def get(self, key, default=None, version=None):
        key = self.make_key(key, version=version)
        self.validate_key(key)
+        pickled = None
        with self._lock.reader():
            exp = self._expire_info.get(key, 0)
            if exp is None or exp > time.time():
-                try:
-                    pickled = self._cache[key]
-                    return pickle.loads(pickled)
-                except pickle.PickleError:
-                    return default
+                pickled = self._cache[key]
+        if pickled is not None:
+            try:
+                return pickle.loads(pickled)
+            except pickle.PickleError:
+                return default
+
        with self._lock.writer():
            try:
                del self._cache[key]
@ -68,12 +72,13 @@ class LocMemCache(BaseCache):
    def set(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
        key = self.make_key(key, version=version)
        self.validate_key(key)
-        with self._lock.writer():
-            try:
-                pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
+        try:
+            pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
+        except pickle.PickleError:
+            pass
+        else:
+            with self._lock.writer():
                self._set(key, pickled, timeout)
-            except pickle.PickleError:
-                pass

    def incr(self, key, delta=1, version=None):
        value = self.get(key, version=version)
@ -81,12 +86,13 @@ class LocMemCache(BaseCache):
            raise ValueError("Key '%s' not found" % key)
        new_value = value + delta
        key = self.make_key(key, version=version)
-        with self._lock.writer():
-            try:
-                pickled = pickle.dumps(new_value, pickle.HIGHEST_PROTOCOL)
+        try:
+            pickled = pickle.dumps(new_value, pickle.HIGHEST_PROTOCOL)
+        except pickle.PickleError:
+            pass
+        else:
+            with self._lock.writer():
                self._cache[key] = pickled
-            except pickle.PickleError:
-                pass
        return new_value

    def has_key(self, key, version=None):
@ -135,6 +141,7 @@ class LocMemCache(BaseCache):
        self._cache.clear()
        self._expire_info.clear()

+
 # For backwards compatibility
 class CacheClass(LocMemCache):
    pass
--- a/django/core/cache/backends/memcached.py
+++ b/django/core/cache/backends/memcached.py
@ -86,7 +86,7 @@ class BaseMemcachedCache(BaseCache):
        self._cache.delete(key)

    def get_many(self, keys, version=None):
-        new_keys = map(lambda x: self.make_key(x, version=version), keys)
+        new_keys = [self.make_key(x, version=version) for x in keys]
        ret = self._cache.get_multi(new_keys)
        if ret:
            _ = {}
--- a/django/core/files/uploadedfile.py
+++ b/django/core/files/uploadedfile.py
@ -23,11 +23,12 @@ class UploadedFile(File):
    """
    DEFAULT_CHUNK_SIZE = 64 * 2**10

-    def __init__(self, file=None, name=None, content_type=None, size=None, charset=None):
+    def __init__(self, file=None, name=None, content_type=None, size=None, charset=None, content_type_extra=None):
        super(UploadedFile, self).__init__(file, name)
        self.size = size
        self.content_type = content_type
        self.charset = charset
+        self.content_type_extra = content_type_extra

    def __repr__(self):
        return force_str("<%s: %s (%s)>" % (
@ -55,13 +56,13 @@ class TemporaryUploadedFile(UploadedFile):
    """
    A file uploaded to a temporary location (i.e. stream-to-disk).
    """
-    def __init__(self, name, content_type, size, charset):
+    def __init__(self, name, content_type, size, charset, content_type_extra):
        if settings.FILE_UPLOAD_TEMP_DIR:
            file = tempfile.NamedTemporaryFile(suffix='.upload',
                dir=settings.FILE_UPLOAD_TEMP_DIR)
        else:
            file = tempfile.NamedTemporaryFile(suffix='.upload')
-        super(TemporaryUploadedFile, self).__init__(file, name, content_type, size, charset)
+        super(TemporaryUploadedFile, self).__init__(file, name, content_type, size, charset, content_type_extra)

    def temporary_file_path(self):
        """
@ -83,8 +84,8 @@ class InMemoryUploadedFile(UploadedFile):
    """
    A file uploaded into memory (i.e. stream-to-memory).
    """
-    def __init__(self, file, field_name, name, content_type, size, charset):
-        super(InMemoryUploadedFile, self).__init__(file, name, content_type, size, charset)
+    def __init__(self, file, field_name, name, content_type, size, charset, content_type_extra):
+        super(InMemoryUploadedFile, self).__init__(file, name, content_type, size, charset, content_type_extra)
        self.field_name = field_name

    def open(self, mode=None):
@ -109,7 +110,7 @@ class SimpleUploadedFile(InMemoryUploadedFile):
    def __init__(self, name, content, content_type='text/plain'):
        content = content or b''
        super(SimpleUploadedFile, self).__init__(BytesIO(content), None, name,
-                                                 content_type, len(content), None)
+                                                 content_type, len(content), None, None)

    def from_dict(cls, file_dict):
        """
--- a/django/core/files/uploadhandler.py
+++ b/django/core/files/uploadhandler.py
@ -64,6 +64,7 @@ class FileUploadHandler(object):
        self.content_type = None
        self.content_length = None
        self.charset = None
+        self.content_type_extra = None
        self.request = request

    def handle_raw_input(self, input_data, META, content_length, boundary, encoding=None):
@ -84,7 +85,7 @@ class FileUploadHandler(object):
        """
        pass

-    def new_file(self, field_name, file_name, content_type, content_length, charset=None):
+    def new_file(self, field_name, file_name, content_type, content_length, charset=None, content_type_extra=None):
        """
        Signal that a new file has been started.

@ -96,6 +97,7 @@ class FileUploadHandler(object):
        self.content_type = content_type
        self.content_length = content_length
        self.charset = charset
+        self.content_type_extra = content_type_extra

    def receive_data_chunk(self, raw_data, start):
        """
@ -132,7 +134,7 @@ class TemporaryFileUploadHandler(FileUploadHandler):
        Create the file object to append to as data is coming in.
        """
        super(TemporaryFileUploadHandler, self).new_file(file_name, *args, **kwargs)
-        self.file = TemporaryUploadedFile(self.file_name, self.content_type, 0, self.charset)
+        self.file = TemporaryUploadedFile(self.file_name, self.content_type, 0, self.charset, self.content_type_extra)

    def receive_data_chunk(self, raw_data, start):
        self.file.write(raw_data)
@ -187,7 +189,8 @@ class MemoryFileUploadHandler(FileUploadHandler):
            name = self.file_name,
            content_type = self.content_type,
            size = file_size,
-            charset = self.charset
+            charset = self.charset,
+            content_type_extra = self.content_type_extra
        )


--- a/django/core/mail/backends/console.py
+++ b/django/core/mail/backends/console.py
@ -16,6 +16,7 @@ class EmailBackend(BaseEmailBackend):
        """Write all messages to the stream in a thread-safe way."""
        if not email_messages:
            return
+        msg_count = 0
        with self._lock:
            try:
                stream_created = self.open()
@ -24,9 +25,10 @@ class EmailBackend(BaseEmailBackend):
                    self.stream.write('-' * 79)
                    self.stream.write('\n')
                    self.stream.flush()  # flush after each message
+                    msg_count += 1
                if stream_created:
                    self.close()
            except:
                if not self.fail_silently:
                    raise
-        return len(email_messages)
+        return msg_count
--- a/django/core/mail/backends/dummy.py
+++ b/django/core/mail/backends/dummy.py
@ -6,4 +6,4 @@ from django.core.mail.backends.base import BaseEmailBackend

 class EmailBackend(BaseEmailBackend):
    def send_messages(self, email_messages):
-        return len(email_messages)
+        return len(list(email_messages))
--- a/django/core/mail/backends/locmem.py
+++ b/django/core/mail/backends/locmem.py
@ -20,7 +20,9 @@ class EmailBackend(BaseEmailBackend):

    def send_messages(self, messages):
        """Redirect messages to the dummy outbox"""
+        msg_count = 0
        for message in messages:  # .message() triggers header validation
            message.message()
+            msg_count += 1
        mail.outbox.extend(messages)
-        return len(messages)
+        return msg_count
--- a/django/core/mail/backends/smtp.py
+++ b/django/core/mail/backends/smtp.py
@ -15,22 +15,18 @@ class EmailBackend(BaseEmailBackend):
    A wrapper that manages the SMTP network connection.
    """
    def __init__(self, host=None, port=None, username=None, password=None,
-                 use_tls=None, fail_silently=False, **kwargs):
+                 use_tls=None, fail_silently=False, use_ssl=None, **kwargs):
        super(EmailBackend, self).__init__(fail_silently=fail_silently)
        self.host = host or settings.EMAIL_HOST
        self.port = port or settings.EMAIL_PORT
-        if username is None:
-            self.username = settings.EMAIL_HOST_USER
-        else:
-            self.username = username
-        if password is None:
-            self.password = settings.EMAIL_HOST_PASSWORD
-        else:
-            self.password = password
-        if use_tls is None:
-            self.use_tls = settings.EMAIL_USE_TLS
-        else:
-            self.use_tls = use_tls
+        self.username = settings.EMAIL_HOST_USER if username is None else username
+        self.password = settings.EMAIL_HOST_PASSWORD if password is None else password
+        self.use_tls = settings.EMAIL_USE_TLS if use_tls is None else use_tls
+        self.use_ssl = settings.EMAIL_USE_SSL if use_ssl is None else use_ssl
+        if self.use_ssl and self.use_tls:
+            raise ValueError(
+                "EMAIL_USE_TLS/EMAIL_USE_SSL are mutually exclusive, so only set "
+                "one of those settings to True.")
        self.connection = None
        self._lock = threading.RLock()

@ -45,12 +41,18 @@ class EmailBackend(BaseEmailBackend):
        try:
            # If local_hostname is not specified, socket.getfqdn() gets used.
            # For performance, we use the cached FQDN for local_hostname.
-            self.connection = smtplib.SMTP(self.host, self.port,
+            if self.use_ssl:
+                self.connection = smtplib.SMTP_SSL(self.host, self.port,
                                           local_hostname=DNS_NAME.get_fqdn())
-            if self.use_tls:
-                self.connection.ehlo()
-                self.connection.starttls()
-                self.connection.ehlo()
+            else:
+                self.connection = smtplib.SMTP(self.host, self.port,
+                                           local_hostname=DNS_NAME.get_fqdn())
+                # TLS/SSL are mutually exclusive, so only attempt TLS over
+                # non-secure connections.
+                if self.use_tls:
+                    self.connection.ehlo()
+                    self.connection.starttls()
+                    self.connection.ehlo()
            if self.username and self.password:
                self.connection.login(self.username, self.password)
            return True
--- a/django/core/mail/message.py
+++ b/django/core/mail/message.py
@ -3,7 +3,6 @@ from __future__ import unicode_literals
 import mimetypes
 import os
 import random
-import sys
 import time
 from email import charset as Charset, encoders as Encoders
 from email.generator import Generator
@ -139,9 +138,6 @@ class SafeMIMEText(MIMEText):
        """
        fp = six.StringIO()
        g = Generator(fp, mangle_from_ = False)
-        if sys.version_info < (2, 6, 6) and isinstance(self._payload, six.text_type):
-            # Workaround for http://bugs.python.org/issue1368247
-            self._payload = self._payload.encode(self._charset.output_charset)
        g.flatten(self, unixfrom=unixfrom)
        return fp.getvalue()

--- a/django/core/signing.py
+++ b/django/core/signing.py
@ -183,6 +183,10 @@ class TimestampSigner(Signer):
        return super(TimestampSigner, self).sign(value)

    def unsign(self, value, max_age=None):
+        """
+        Retrieve original value and check it wasn't signed more
+        than max_age seconds ago.
+        """
        result =  super(TimestampSigner, self).unsign(value)
        value, timestamp = result.rsplit(self.sep, 1)
        timestamp = baseconv.base62.decode(timestamp)
--- a/django/core/validators.py
+++ b/django/core/validators.py
@ -87,7 +87,7 @@ class EmailValidator(object):
        r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"$)', # quoted-string
        re.IGNORECASE)
    domain_regex = re.compile(
-        r'(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?$)'  # domain
+        r'(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}|[A-Z0-9-]{2,})\.?$'  # domain
        # literal form, ipv4 address (SMTP 4.1.3)
        r'|^\[(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}\]$',
        re.IGNORECASE)
--- a/django/db/init.py
+++ b/django/db/init.py
@ -1,20 +1,25 @@
 import warnings

 from django.core import signals
-from django.db.utils import (DEFAULT_DB_ALIAS,
-    DataError, OperationalError, IntegrityError, InternalError,
-    ProgrammingError, NotSupportedError, DatabaseError,
-    InterfaceError, Error,
-    load_backend, ConnectionHandler, ConnectionRouter)
+from django.db.utils import (DEFAULT_DB_ALIAS, DataError, OperationalError,
+    IntegrityError, InternalError, ProgrammingError, NotSupportedError,
+    DatabaseError, InterfaceError, Error, load_backend,
+    ConnectionHandler, ConnectionRouter)
 from django.utils.functional import cached_property

-__all__ = ('backend', 'connection', 'connections', 'router', 'DatabaseError',
-    'IntegrityError', 'DEFAULT_DB_ALIAS')
+
+__all__ = [
+    'backend', 'connection', 'connections', 'router', 'DatabaseError',
+    'IntegrityError', 'InternalError', 'ProgrammingError', 'DataError',
+    'NotSupportedError', 'Error', 'InterfaceError', 'OperationalError',
+    'DEFAULT_DB_ALIAS'
+]

 connections = ConnectionHandler()

 router = ConnectionRouter()

+
 # `connection`, `DatabaseError` and `IntegrityError` are convenient aliases
 # for backend bits.

@ -39,8 +44,15 @@ class DefaultConnectionProxy(object):
    def __delattr__(self, name):
        return delattr(connections[DEFAULT_DB_ALIAS], name)

+    def __eq__(self, other):
+        return connections[DEFAULT_DB_ALIAS] == other
+
+    def __ne__(self, other):
+        return connections[DEFAULT_DB_ALIAS] != other
+
 connection = DefaultConnectionProxy()

+
 class DefaultBackendProxy(object):
    """
    Temporary proxy class used during deprecation period of the `backend` module
@ -63,6 +75,7 @@ class DefaultBackendProxy(object):

 backend = DefaultBackendProxy()

+
 def close_connection(**kwargs):
    warnings.warn(
        "close_connection is superseded by close_old_connections.",
@ -76,12 +89,14 @@ def close_connection(**kwargs):
        transaction.abort(conn)
        connections[conn].close()

+
 # Register an event to reset saved queries when a Django request is started.
 def reset_queries(**kwargs):
    for conn in connections.all():
        conn.queries = []
 signals.request_started.connect(reset_queries)

+
 # Register an event to reset transaction state and close connections past
 # their lifetime. NB: abort() doesn't do anything outside of a transaction.
 def close_old_connections(**kwargs):
--- a/django/db/backends/init.py
+++ b/django/db/backends/init.py
@ -70,7 +70,9 @@ class BaseDatabaseWrapper(object):
        self._thread_ident = thread.get_ident()

    def __eq__(self, other):
-        return self.alias == other.alias
+        if isinstance(other, BaseDatabaseWrapper):
+            return self.alias == other.alias
+        return NotImplemented

    def __ne__(self, other):
        return not self == other
@ -1184,6 +1186,7 @@ FieldInfo = namedtuple('FieldInfo',
    'name type_code display_size internal_size precision scale null_ok'
 )

+
 class BaseDatabaseIntrospection(object):
    """
    This class encapsulates all backend-specific introspection utilities
--- a/django/db/backends/creation.py
+++ b/django/db/backends/creation.py
@ -253,12 +253,13 @@ class BaseDatabaseCreation(object):
            r_col = model._meta.get_field(f.rel.field_name).column
            r_name = '%s_refs_%s_%s' % (
                col, r_col, self._digest(table, r_table))
-            output.append('%s %s %s %s;' % \
-                (style.SQL_KEYWORD('ALTER TABLE'),
+            output.append('%s %s %s %s;' % (
+                style.SQL_KEYWORD('ALTER TABLE'),
                style.SQL_TABLE(qn(table)),
                style.SQL_KEYWORD(self.connection.ops.drop_foreignkey_sql()),
                style.SQL_FIELD(qn(truncate_name(
-                    r_name, self.connection.ops.max_name_length())))))
+                    r_name, self.connection.ops.max_name_length())))
+            ))
        del references_to_delete[model]
        return output

--- a/django/db/backends/dummy/base.py
+++ b/django/db/backends/dummy/base.py
@ -8,33 +8,43 @@ ImproperlyConfigured.
 """

 from django.core.exceptions import ImproperlyConfigured
-from django.db.backends import *
+from django.db.backends import (BaseDatabaseOperations, BaseDatabaseClient,
+    BaseDatabaseIntrospection, BaseDatabaseWrapper, BaseDatabaseFeatures,
+    BaseDatabaseValidation)
 from django.db.backends.creation import BaseDatabaseCreation

+
 def complain(*args, **kwargs):
    raise ImproperlyConfigured("settings.DATABASES is improperly configured. "
                               "Please supply the ENGINE value. Check "
                               "settings documentation for more details.")

+
 def ignore(*args, **kwargs):
    pass

+
 class DatabaseError(Exception):
    pass

+
 class IntegrityError(DatabaseError):
    pass

+
 class DatabaseOperations(BaseDatabaseOperations):
    quote_name = complain

+
 class DatabaseClient(BaseDatabaseClient):
    runshell = complain

+
 class DatabaseCreation(BaseDatabaseCreation):
    create_test_db = ignore
    destroy_test_db = ignore

+
 class DatabaseIntrospection(BaseDatabaseIntrospection):
    get_table_list = complain
    get_table_description = complain
@ -42,6 +52,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
    get_indexes = complain
    get_key_columns = complain

+
 class DatabaseWrapper(BaseDatabaseWrapper):
    operators = {}
    # Override the base class implementations with null
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@ -37,7 +37,8 @@ except ImportError:

 from django.conf import settings
 from django.db import utils
-from django.db.backends import *
+from django.db.backends import (util, BaseDatabaseFeatures,
+    BaseDatabaseOperations, BaseDatabaseWrapper)
 from django.db.backends.mysql.client import DatabaseClient
 from django.db.backends.mysql.creation import DatabaseCreation
 from django.db.backends.mysql.introspection import DatabaseIntrospection
@ -60,6 +61,7 @@ IntegrityError = Database.IntegrityError
 # It's impossible to import datetime_or_None directly from MySQLdb.times
 parse_datetime = conversions[FIELD_TYPE.DATETIME]

+
 def parse_datetime_with_timezone_support(value):
    dt = parse_datetime(value)
    # Confirm that dt is naive before overwriting its tzinfo.
@ -67,6 +69,7 @@ def parse_datetime_with_timezone_support(value):
        dt = dt.replace(tzinfo=timezone.utc)
    return dt

+
 def adapt_datetime_with_timezone_support(value, conv):
    # Equivalent to DateTimeField.get_db_prep_value. Used only by raw SQL.
    if settings.USE_TZ:
@ -101,6 +104,7 @@ django_conversions.update({
 # http://dev.mysql.com/doc/refman/5.0/en/news.html .
 server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})')

+
 # MySQLdb-1.2.1 and newer automatically makes use of SHOW WARNINGS on
 # MySQL-4.1 and newer, so the MysqlDebugWrapper is unnecessary. Since the
 # point is to raise Warnings as exceptions, this can be done with the Python
@ -151,6 +155,7 @@ class CursorWrapper(object):
    def __iter__(self):
        return iter(self.cursor)

+
 class DatabaseFeatures(BaseDatabaseFeatures):
    empty_fetchmany_value = ()
    update_can_self_select = False
@ -208,6 +213,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
        cursor.execute("SELECT 1 FROM mysql.time_zone LIMIT 1")
        return cursor.fetchone() is not None

+
 class DatabaseOperations(BaseDatabaseOperations):
    compiler_module = "django.db.backends.mysql.compiler"

@ -323,7 +329,7 @@ class DatabaseOperations(BaseDatabaseOperations):
        # Truncate already resets the AUTO_INCREMENT field from
        # MySQL version 5.0.13 onwards. Refs #16961.
        if self.connection.mysql_version < (5, 0, 13):
-            return ["%s %s %s %s %s;" % \
+            return ["%s %s %s %s %s;" %
                    (style.SQL_KEYWORD('ALTER'),
                    style.SQL_KEYWORD('TABLE'),
                    style.SQL_TABLE(self.quote_name(sequence['table'])),
@ -377,6 +383,7 @@ class DatabaseOperations(BaseDatabaseOperations):
        items_sql = "(%s)" % ", ".join(["%s"] * len(fields))
        return "VALUES " + ", ".join([items_sql] * num_values)

+
 class DatabaseWrapper(BaseDatabaseWrapper):
    vendor = 'mysql'
    operators = {
--- a/django/db/backends/mysql/client.py
+++ b/django/db/backends/mysql/client.py
@ -3,6 +3,7 @@ import sys

 from django.db.backends import BaseDatabaseClient

+
 class DatabaseClient(BaseDatabaseClient):
    executable_name = 'mysql'

@ -37,4 +38,3 @@ class DatabaseClient(BaseDatabaseClient):
            sys.exit(os.system(" ".join(args)))
        else:
            os.execvp(self.executable_name, args)
-
--- a/django/db/backends/mysql/compiler.py
+++ b/django/db/backends/mysql/compiler.py
@ -22,20 +22,26 @@ class SQLCompiler(compiler.SQLCompiler):
        sql, params = self.as_sql()
        return '(%s) IN (%s)' % (', '.join(['%s.%s' % (qn(alias), qn2(column)) for column in columns]), sql), params

+
 class SQLInsertCompiler(compiler.SQLInsertCompiler, SQLCompiler):
    pass

+
 class SQLDeleteCompiler(compiler.SQLDeleteCompiler, SQLCompiler):
    pass

+
 class SQLUpdateCompiler(compiler.SQLUpdateCompiler, SQLCompiler):
    pass

+
 class SQLAggregateCompiler(compiler.SQLAggregateCompiler, SQLCompiler):
    pass

+
 class SQLDateCompiler(compiler.SQLDateCompiler, SQLCompiler):
    pass

+
 class SQLDateTimeCompiler(compiler.SQLDateTimeCompiler, SQLCompiler):
    pass
--- a/django/db/backends/mysql/creation.py
+++ b/django/db/backends/mysql/creation.py
@ -1,34 +1,35 @@
 from django.db.backends.creation import BaseDatabaseCreation

+
 class DatabaseCreation(BaseDatabaseCreation):
    # This dictionary maps Field objects to their associated MySQL column
    # types, as strings. Column-type strings can contain format strings; they'll
    # be interpolated against the values of Field.__dict__ before being output.
    # If a column type is set to None, it won't be included in the output.
    data_types = {
-        'AutoField':         'integer AUTO_INCREMENT',
-        'BinaryField':       'longblob',
-        'BooleanField':      'bool',
-        'CharField':         'varchar(%(max_length)s)',
+        'AutoField': 'integer AUTO_INCREMENT',
+        'BinaryField': 'longblob',
+        'BooleanField': 'bool',
+        'CharField': 'varchar(%(max_length)s)',
        'CommaSeparatedIntegerField': 'varchar(%(max_length)s)',
-        'DateField':         'date',
-        'DateTimeField':     'datetime',
-        'DecimalField':      'numeric(%(max_digits)s, %(decimal_places)s)',
-        'FileField':         'varchar(%(max_length)s)',
-        'FilePathField':     'varchar(%(max_length)s)',
-        'FloatField':        'double precision',
-        'IntegerField':      'integer',
-        'BigIntegerField':   'bigint',
-        'IPAddressField':    'char(15)',
+        'DateField': 'date',
+        'DateTimeField': 'datetime',
+        'DecimalField': 'numeric(%(max_digits)s, %(decimal_places)s)',
+        'FileField': 'varchar(%(max_length)s)',
+        'FilePathField': 'varchar(%(max_length)s)',
+        'FloatField': 'double precision',
+        'IntegerField': 'integer',
+        'BigIntegerField': 'bigint',
+        'IPAddressField': 'char(15)',
        'GenericIPAddressField': 'char(39)',
-        'NullBooleanField':  'bool',
-        'OneToOneField':     'integer',
+        'NullBooleanField': 'bool',
+        'OneToOneField': 'integer',
        'PositiveIntegerField': 'integer UNSIGNED',
        'PositiveSmallIntegerField': 'smallint UNSIGNED',
-        'SlugField':         'varchar(%(max_length)s)',
+        'SlugField': 'varchar(%(max_length)s)',
        'SmallIntegerField': 'smallint',
-        'TextField':         'longtext',
-        'TimeField':         'time',
+        'TextField': 'longtext',
+        'TimeField': 'time',
    }

    def sql_table_creation_suffix(self):
--- a/django/db/backends/mysql/introspection.py
+++ b/django/db/backends/mysql/introspection.py
@ -7,6 +7,7 @@ from django.utils.encoding import force_text

 foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")

+
 class DatabaseIntrospection(BaseDatabaseIntrospection):
    data_types_reverse = {
        FIELD_TYPE.BLOB: 'TextField',
--- a/django/db/backends/mysql/validation.py
+++ b/django/db/backends/mysql/validation.py
@ -1,5 +1,6 @@
 from django.db.backends import BaseDatabaseValidation

+
 class DatabaseValidation(BaseDatabaseValidation):
    def validate_field(self, errors, opts, f):
        """
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@ -7,11 +7,12 @@ from __future__ import unicode_literals

 import decimal
 import re
+import platform
 import sys
 import warnings

+
 def _setup_environment(environ):
-    import platform
    # Cygwin requires some special voodoo to set the environment variables
    # properly so that Oracle will see them.
    if platform.system().upper().startswith('CYGWIN'):
@ -91,6 +92,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
    supports_tablespaces = True
    supports_sequence_reset = False

+
 class DatabaseOperations(BaseDatabaseOperations):
    compiler_module = "django.db.backends.oracle.compiler"

@ -268,7 +270,7 @@ WHEN (new.%(col_name)s IS NULL)
        # http://cx-oracle.sourceforge.net/html/cursor.html#Cursor.statement
        # The DB API definition does not define this attribute.
        statement = cursor.statement
-        if not six.PY3 and not isinstance(statement, unicode):
+        if statement and not six.PY3 and not isinstance(statement, unicode):
            statement = statement.decode('utf-8')
        # Unlike Psycopg's `query` and MySQLdb`'s `_last_executed`, CxOracle's
        # `statement` doesn't contain the query parameters. refs #20010.
@ -309,7 +311,7 @@ WHEN (new.%(col_name)s IS NULL)
        # Oracle puts the query text into a (query % args) construct, so % signs
        # in names need to be escaped. The '%%' will be collapsed back to '%' at
        # that stage so we aren't really making the name longer here.
-        name = name.replace('%','%%')
+        name = name.replace('%', '%%')
        return name.upper()

    def random_function_sql(self):
@ -763,7 +765,7 @@ class FormatStylePlaceholderCursor(object):

    def _format_params(self, params):
        try:
-            return dict((k,OracleParam(v, self, True)) for k,v in params.items())
+            return dict((k, OracleParam(v, self, True)) for k, v in params.items())
        except AttributeError:
            return tuple([OracleParam(p, self, True) for p in params])

@ -783,12 +785,12 @@ class FormatStylePlaceholderCursor(object):
                for i, value in enumerate(params):
                    if value.input_size:
                        sizes[i] = value.input_size
-            self.setinputsizes(*sizes)        
+            self.setinputsizes(*sizes)

    def _param_generator(self, params):
        # Try dict handling; if that fails, treat as sequence
        if hasattr(params, 'items'):
-            return dict((k, v.force_bytes) for k,v in params.items())
+            return dict((k, v.force_bytes) for k, v in params.items())
        else:
            return [p.force_bytes for p in params]

@ -804,14 +806,14 @@ class FormatStylePlaceholderCursor(object):
            query = convert_unicode(query, self.charset)
        elif hasattr(params, 'keys'):
            # Handle params as dict
-            args = dict((k, ":%s"%k) for k in params.keys())
+            args = dict((k, ":%s" % k) for k in params.keys())
            query = convert_unicode(query % args, self.charset)
        else:
            # Handle params as sequence
            args = [(':arg%d' % i) for i in range(len(params))]
            query = convert_unicode(query % tuple(args), self.charset)
        return query, self._format_params(params)
-        
+
    def execute(self, query, params=None):
        query, params = self._fix_for_params(query, params)
        self._guess_input_sizes([params])
@ -830,9 +832,9 @@ class FormatStylePlaceholderCursor(object):
        # uniform treatment for sequences and iterables
        params_iter = iter(params)
        query, firstparams = self._fix_for_params(query, next(params_iter))
-        # we build a list of formatted params; as we're going to traverse it 
+        # we build a list of formatted params; as we're going to traverse it
        # more than once, we can't make it lazy by using a generator
-        formatted = [firstparams]+[self._format_params(p) for p in params_iter]
+        formatted = [firstparams] + [self._format_params(p) for p in params_iter]
        self._guess_input_sizes(formatted)
        try:
            return self.cursor.executemany(query,
--- a/django/db/backends/oracle/client.py
+++ b/django/db/backends/oracle/client.py
@ -3,6 +3,7 @@ import sys

 from django.db.backends import BaseDatabaseClient

+
 class DatabaseClient(BaseDatabaseClient):
    executable_name = 'sqlplus'

@ -13,4 +14,3 @@ class DatabaseClient(BaseDatabaseClient):
            sys.exit(os.system(" ".join(args)))
        else:
            os.execvp(self.executable_name, args)
-
--- a/django/db/backends/oracle/compiler.py
+++ b/django/db/backends/oracle/compiler.py
@ -60,17 +60,22 @@ class SQLCompiler(compiler.SQLCompiler):
 class SQLInsertCompiler(compiler.SQLInsertCompiler, SQLCompiler):
    pass

+
 class SQLDeleteCompiler(compiler.SQLDeleteCompiler, SQLCompiler):
    pass

+
 class SQLUpdateCompiler(compiler.SQLUpdateCompiler, SQLCompiler):
    pass

+
 class SQLAggregateCompiler(compiler.SQLAggregateCompiler, SQLCompiler):
    pass

+
 class SQLDateCompiler(compiler.SQLDateCompiler, SQLCompiler):
    pass

+
 class SQLDateTimeCompiler(compiler.SQLDateTimeCompiler, SQLCompiler):
    pass
--- a/django/db/backends/oracle/creation.py
+++ b/django/db/backends/oracle/creation.py
@ -5,9 +5,11 @@ from django.conf import settings
 from django.db.backends.creation import BaseDatabaseCreation
 from django.utils.six.moves import input

+
 TEST_DATABASE_PREFIX = 'test_'
 PASSWORD = 'Im_a_lumberjack'

+
 class DatabaseCreation(BaseDatabaseCreation):
    # This dictionary maps Field objects to their associated Oracle column
    # types, as strings. Column-type strings can contain format strings; they'll
@ -18,30 +20,30 @@ class DatabaseCreation(BaseDatabaseCreation):
    # output (the "qn_" prefix is stripped before the lookup is performed.

    data_types = {
-        'AutoField':                    'NUMBER(11)',
-        'BinaryField':                  'BLOB',
-        'BooleanField':                 'NUMBER(1)',
-        'CharField':                    'NVARCHAR2(%(max_length)s)',
-        'CommaSeparatedIntegerField':   'VARCHAR2(%(max_length)s)',
-        'DateField':                    'DATE',
-        'DateTimeField':                'TIMESTAMP',
-        'DecimalField':                 'NUMBER(%(max_digits)s, %(decimal_places)s)',
-        'FileField':                    'NVARCHAR2(%(max_length)s)',
-        'FilePathField':                'NVARCHAR2(%(max_length)s)',
-        'FloatField':                   'DOUBLE PRECISION',
-        'IntegerField':                 'NUMBER(11)',
-        'BigIntegerField':              'NUMBER(19)',
-        'IPAddressField':               'VARCHAR2(15)',
-        'GenericIPAddressField':        'VARCHAR2(39)',
-        'NullBooleanField':             'NUMBER(1)',
-        'OneToOneField':                'NUMBER(11)',
-        'PositiveIntegerField':         'NUMBER(11)',
-        'PositiveSmallIntegerField':    'NUMBER(11)',
-        'SlugField':                    'NVARCHAR2(%(max_length)s)',
-        'SmallIntegerField':            'NUMBER(11)',
-        'TextField':                    'NCLOB',
-        'TimeField':                    'TIMESTAMP',
-        'URLField':                     'VARCHAR2(%(max_length)s)',
+        'AutoField': 'NUMBER(11)',
+        'BinaryField': 'BLOB',
+        'BooleanField': 'NUMBER(1)',
+        'CharField': 'NVARCHAR2(%(max_length)s)',
+        'CommaSeparatedIntegerField': 'VARCHAR2(%(max_length)s)',
+        'DateField': 'DATE',
+        'DateTimeField': 'TIMESTAMP',
+        'DecimalField': 'NUMBER(%(max_digits)s, %(decimal_places)s)',
+        'FileField': 'NVARCHAR2(%(max_length)s)',
+        'FilePathField': 'NVARCHAR2(%(max_length)s)',
+        'FloatField': 'DOUBLE PRECISION',
+        'IntegerField': 'NUMBER(11)',
+        'BigIntegerField': 'NUMBER(19)',
+        'IPAddressField': 'VARCHAR2(15)',
+        'GenericIPAddressField': 'VARCHAR2(39)',
+        'NullBooleanField': 'NUMBER(1)',
+        'OneToOneField': 'NUMBER(11)',
+        'PositiveIntegerField': 'NUMBER(11)',
+        'PositiveSmallIntegerField': 'NUMBER(11)',
+        'SlugField': 'NVARCHAR2(%(max_length)s)',
+        'SmallIntegerField': 'NUMBER(11)',
+        'TextField': 'NCLOB',
+        'TimeField': 'TIMESTAMP',
+        'URLField': 'VARCHAR2(%(max_length)s)',
    }

    data_type_check_constraints = {
@ -190,7 +192,7 @@ class DatabaseCreation(BaseDatabaseCreation):
        statements = [
            'DROP TABLESPACE %(tblspace)s INCLUDING CONTENTS AND DATAFILES CASCADE CONSTRAINTS',
            'DROP TABLESPACE %(tblspace_temp)s INCLUDING CONTENTS AND DATAFILES CASCADE CONSTRAINTS',
-            ]
+        ]
        self._execute_statements(cursor, statements, parameters, verbosity)

    def _destroy_test_user(self, cursor, parameters, verbosity):
--- a/django/db/backends/oracle/introspection.py
+++ b/django/db/backends/oracle/introspection.py
@ -1,10 +1,13 @@
-from django.db.backends import BaseDatabaseIntrospection, FieldInfo
-from django.utils.encoding import force_text
-import cx_Oracle
 import re

+import cx_Oracle
+
+from django.db.backends import BaseDatabaseIntrospection, FieldInfo
+from django.utils.encoding import force_text
+
 foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")

+
 class DatabaseIntrospection(BaseDatabaseIntrospection):
    # Maps type objects to Django Field types.
    data_types_reverse = {
@ -95,11 +98,11 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
            SELECT ccol.column_name, rcol.table_name AS referenced_table, rcol.column_name AS referenced_column
            FROM user_constraints c
            JOIN user_cons_columns ccol
-              ON ccol.constraint_name = c.constraint_name 
+              ON ccol.constraint_name = c.constraint_name
            JOIN user_cons_columns rcol
-              ON rcol.constraint_name = c.r_constraint_name 
-            WHERE c.table_name = %s AND c.constraint_type = 'R'""" , [table_name.upper()])
-        return [tuple(cell.lower() for cell in row) 
+              ON rcol.constraint_name = c.r_constraint_name
+            WHERE c.table_name = %s AND c.constraint_type = 'R'""", [table_name.upper()])
+        return [tuple(cell.lower() for cell in row)
                for row in cursor.fetchall()]

    def get_indexes(self, cursor, table_name):
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@ -6,7 +6,9 @@ Requires psycopg 2: http://initd.org/projects/psycopg2
 import logging
 import sys

-from django.db.backends import *
+from django.conf import settings
+from django.db.backends import (BaseDatabaseFeatures, BaseDatabaseWrapper,
+    BaseDatabaseValidation)
 from django.db.backends.postgresql_psycopg2.operations import DatabaseOperations
 from django.db.backends.postgresql_psycopg2.client import DatabaseClient
 from django.db.backends.postgresql_psycopg2.creation import DatabaseCreation
@ -34,11 +36,13 @@ psycopg2.extensions.register_adapter(SafeText, psycopg2.extensions.QuotedString)

 logger = logging.getLogger('django.db.backends')

+
 def utc_tzinfo_factory(offset):
    if offset != 0:
        raise AssertionError("database connection isn't set to UTC")
    return utc

+
 class DatabaseFeatures(BaseDatabaseFeatures):
    needs_datetime_string_cast = False
    can_return_id_from_insert = True
@ -55,6 +59,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
    can_rollback_ddl = True
    supports_combined_alters = True

+
 class DatabaseWrapper(BaseDatabaseWrapper):
    vendor = 'postgresql'
    operators = {
@ -135,7 +140,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                # Set the time zone in autocommit mode (see #17062)
                self.set_autocommit(True)
                self.connection.cursor().execute(
-                        self.ops.set_time_zone_sql(), [tz])
+                    self.ops.set_time_zone_sql(), [tz]
+                )
        self.connection.set_isolation_level(self.isolation_level)

    def create_cursor(self):
--- a/django/db/backends/postgresql_psycopg2/client.py
+++ b/django/db/backends/postgresql_psycopg2/client.py
@ -3,6 +3,7 @@ import sys

 from django.db.backends import BaseDatabaseClient

+
 class DatabaseClient(BaseDatabaseClient):
    executable_name = 'psql'

@ -20,4 +21,3 @@ class DatabaseClient(BaseDatabaseClient):
            sys.exit(os.system(" ".join(args)))
        else:
            os.execvp(self.executable_name, args)
-
--- a/django/db/backends/postgresql_psycopg2/creation.py
+++ b/django/db/backends/postgresql_psycopg2/creation.py
@ -8,29 +8,29 @@ class DatabaseCreation(BaseDatabaseCreation):
    # be interpolated against the values of Field.__dict__ before being output.
    # If a column type is set to None, it won't be included in the output.
    data_types = {
-        'AutoField':         'serial',
-        'BinaryField':       'bytea',
-        'BooleanField':      'boolean',
-        'CharField':         'varchar(%(max_length)s)',
+        'AutoField': 'serial',
+        'BinaryField': 'bytea',
+        'BooleanField': 'boolean',
+        'CharField': 'varchar(%(max_length)s)',
        'CommaSeparatedIntegerField': 'varchar(%(max_length)s)',
-        'DateField':         'date',
-        'DateTimeField':     'timestamp with time zone',
-        'DecimalField':      'numeric(%(max_digits)s, %(decimal_places)s)',
-        'FileField':         'varchar(%(max_length)s)',
-        'FilePathField':     'varchar(%(max_length)s)',
-        'FloatField':        'double precision',
-        'IntegerField':      'integer',
-        'BigIntegerField':   'bigint',
-        'IPAddressField':    'inet',
+        'DateField': 'date',
+        'DateTimeField': 'timestamp with time zone',
+        'DecimalField': 'numeric(%(max_digits)s, %(decimal_places)s)',
+        'FileField': 'varchar(%(max_length)s)',
+        'FilePathField': 'varchar(%(max_length)s)',
+        'FloatField': 'double precision',
+        'IntegerField': 'integer',
+        'BigIntegerField': 'bigint',
+        'IPAddressField': 'inet',
        'GenericIPAddressField': 'inet',
-        'NullBooleanField':  'boolean',
-        'OneToOneField':     'integer',
+        'NullBooleanField': 'boolean',
+        'OneToOneField': 'integer',
        'PositiveIntegerField': 'integer',
        'PositiveSmallIntegerField': 'smallint',
-        'SlugField':         'varchar(%(max_length)s)',
+        'SlugField': 'varchar(%(max_length)s)',
        'SmallIntegerField': 'smallint',
-        'TextField':         'text',
-        'TimeField':         'time',
+        'TextField': 'text',
+        'TimeField': 'time',
    }

    data_type_check_constraints = {
@ -59,7 +59,7 @@ class DatabaseCreation(BaseDatabaseCreation):

            def get_index_sql(index_name, opclass=''):
                return (style.SQL_KEYWORD('CREATE INDEX') + ' ' +
-                        style.SQL_TABLE(qn(truncate_name(index_name,self.connection.ops.max_name_length()))) + ' ' +
+                        style.SQL_TABLE(qn(truncate_name(index_name, self.connection.ops.max_name_length()))) + ' ' +
                        style.SQL_KEYWORD('ON') + ' ' +
                        style.SQL_TABLE(qn(db_table)) + ' ' +
                        "(%s%s)" % (style.SQL_FIELD(qn(f.column)), opclass) +
--- a/django/db/backends/postgresql_psycopg2/introspection.py
+++ b/django/db/backends/postgresql_psycopg2/introspection.py
@ -25,7 +25,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
        1266: 'TimeField',
        1700: 'DecimalField',
    }
-        
+
    def get_table_list(self, cursor):
        "Returns a list of table names in the current database."
        cursor.execute("""
@ -47,7 +47,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
            WHERE table_name = %s""", [table_name])
        null_map = dict(cursor.fetchall())
        cursor.execute("SELECT * FROM %s LIMIT 1" % self.connection.ops.quote_name(table_name))
-        return [FieldInfo(*((force_text(line[0]),) + line[1:6] + (null_map[force_text(line[0])]=='YES',)))
+        return [FieldInfo(*((force_text(line[0]),) + line[1:6] + (null_map[force_text(line[0])] == 'YES',)))
                for line in cursor.description]

    def get_relations(self, cursor, table_name):
@ -81,7 +81,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                ON ccu.constraint_catalog = tc.constraint_catalog
                    AND ccu.constraint_schema = tc.constraint_schema
                    AND ccu.constraint_name = tc.constraint_name
-            WHERE kcu.table_name = %s AND tc.constraint_type = 'FOREIGN KEY'""" , [table_name])
+            WHERE kcu.table_name = %s AND tc.constraint_type = 'FOREIGN KEY'""", [table_name])
        key_columns.extend(cursor.fetchall())
        return key_columns

--- a/django/db/backends/postgresql_psycopg2/operations.py
+++ b/django/db/backends/postgresql_psycopg2/operations.py
@ -135,7 +135,7 @@ class DatabaseOperations(BaseDatabaseOperations):
                # This will be the case if it's an m2m using an autogenerated
                # intermediate table (see BaseDatabaseIntrospection.sequence_list)
                column_name = 'id'
-            sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" % \
+            sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" %
                (style.SQL_KEYWORD('SELECT'),
                style.SQL_TABLE(self.quote_name(table_name)),
                style.SQL_FIELD(column_name))
@ -161,7 +161,7 @@ class DatabaseOperations(BaseDatabaseOperations):

            for f in model._meta.local_fields:
                if isinstance(f, models.AutoField):
-                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
+                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" %
                        (style.SQL_KEYWORD('SELECT'),
                        style.SQL_TABLE(qn(model._meta.db_table)),
                        style.SQL_FIELD(f.column),
@ -173,7 +173,7 @@ class DatabaseOperations(BaseDatabaseOperations):
                    break # Only one AutoField is allowed per model, so don't bother continuing.
            for f in model._meta.many_to_many:
                if not f.rel.through:
-                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
+                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" %
                        (style.SQL_KEYWORD('SELECT'),
                        style.SQL_TABLE(qn(f.m2m_db_table())),
                        style.SQL_FIELD('id'),
--- a/django/db/backends/postgresql_psycopg2/version.py
+++ b/django/db/backends/postgresql_psycopg2/version.py
@ -19,7 +19,8 @@ def _parse_version(text):
    try:
        return int(major) * 10000 + int(major2) * 100 + int(minor)
    except (ValueError, TypeError):
-        return int(major) * 10000 +  int(major2) * 100
+        return int(major) * 10000 + int(major2) * 100
+

 def get_version(connection):
    """
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@ -11,8 +11,10 @@ import decimal
 import warnings
 import re

+from django.conf import settings
 from django.db import utils
-from django.db.backends import *
+from django.db.backends import (util, BaseDatabaseFeatures,
+    BaseDatabaseOperations, BaseDatabaseWrapper, BaseDatabaseValidation)
 from django.db.backends.sqlite3.client import DatabaseClient
 from django.db.backends.sqlite3.creation import DatabaseCreation
 from django.db.backends.sqlite3.introspection import DatabaseIntrospection
@ -43,6 +45,7 @@ except ImportError:
 DatabaseError = Database.DatabaseError
 IntegrityError = Database.IntegrityError

+
 def parse_datetime_with_timezone_support(value):
    dt = parse_datetime(value)
    # Confirm that dt is naive before overwriting its tzinfo.
@ -50,6 +53,7 @@ def parse_datetime_with_timezone_support(value):
        dt = dt.replace(tzinfo=timezone.utc)
    return dt

+
 def adapt_datetime_with_timezone_support(value):
    # Equivalent to DateTimeField.get_db_prep_value. Used only by raw SQL.
    if settings.USE_TZ:
@ -62,6 +66,7 @@ def adapt_datetime_with_timezone_support(value):
        value = value.astimezone(timezone.utc).replace(tzinfo=None)
    return value.isoformat(str(" "))

+
 def decoder(conv_func):
    """ The Python sqlite3 interface returns always byte strings.
        This function converts the received value to a regular string before
@ -82,6 +87,7 @@ Database.register_adapter(decimal.Decimal, util.rev_typecast_decimal)
 Database.register_adapter(str, lambda s: s.decode('utf-8'))
 Database.register_adapter(SafeBytes, lambda s: s.decode('utf-8'))

+
 class DatabaseFeatures(BaseDatabaseFeatures):
    # SQLite cannot handle us only partially reading from a cursor's result set
    # and then writing the same rows to the database in another cursor. This
@ -127,6 +133,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
    def has_zoneinfo_database(self):
        return pytz is not None

+
 class DatabaseOperations(BaseDatabaseOperations):
    def bulk_batch_size(self, fields, objs):
        """
@ -275,6 +282,7 @@ class DatabaseOperations(BaseDatabaseOperations):
        res.extend(["UNION ALL SELECT %s" % ", ".join(["%s"] * len(fields))] * (num_values - 1))
        return " ".join(res)

+
 class DatabaseWrapper(BaseDatabaseWrapper):
    vendor = 'sqlite'
    # SQLite requires LIKE statements to include an ESCAPE clause if the value
@ -433,6 +441,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):

 FORMAT_QMARK_REGEX = re.compile(r'(?<!%)%s')

+
 class SQLiteCursorWrapper(Database.Cursor):
    """
    Django uses "format" style placeholders, but pysqlite2 uses "qmark" style.
@ -452,6 +461,7 @@ class SQLiteCursorWrapper(Database.Cursor):
    def convert_query(self, query):
        return FORMAT_QMARK_REGEX.sub('?', query).replace('%%', '%')

+
 def _sqlite_date_extract(lookup_type, dt):
    if dt is None:
        return None
@ -464,6 +474,7 @@ def _sqlite_date_extract(lookup_type, dt):
    else:
        return getattr(dt, lookup_type)

+
 def _sqlite_date_trunc(lookup_type, dt):
    try:
        dt = util.typecast_timestamp(dt)
@ -476,6 +487,7 @@ def _sqlite_date_trunc(lookup_type, dt):
    elif lookup_type == 'day':
        return "%i-%02i-%02i" % (dt.year, dt.month, dt.day)

+
 def _sqlite_datetime_extract(lookup_type, dt, tzname):
    if dt is None:
        return None
@ -490,6 +502,7 @@ def _sqlite_datetime_extract(lookup_type, dt, tzname):
    else:
        return getattr(dt, lookup_type)

+
 def _sqlite_datetime_trunc(lookup_type, dt, tzname):
    try:
        dt = util.typecast_timestamp(dt)
@ -510,6 +523,7 @@ def _sqlite_datetime_trunc(lookup_type, dt, tzname):
    elif lookup_type == 'second':
        return "%i-%02i-%02i %02i:%02i:%02i" % (dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second)

+
 def _sqlite_format_dtdelta(dt, conn, days, secs, usecs):
    try:
        dt = util.typecast_timestamp(dt)
@ -524,5 +538,6 @@ def _sqlite_format_dtdelta(dt, conn, days, secs, usecs):
    # It will be formatted as "%Y-%m-%d" or "%Y-%m-%d %H:%M:%S[.%f]"
    return str(dt)

+
 def _sqlite_regexp(re_pattern, re_string):
    return bool(re.search(re_pattern, force_text(re_string))) if re_string is not None else False
--- a/django/db/backends/sqlite3/client.py
+++ b/django/db/backends/sqlite3/client.py
@ -3,6 +3,7 @@ import sys

 from django.db.backends import BaseDatabaseClient

+
 class DatabaseClient(BaseDatabaseClient):
    executable_name = 'sqlite3'

@ -13,4 +14,3 @@ class DatabaseClient(BaseDatabaseClient):
            sys.exit(os.system(" ".join(args)))
        else:
            os.execvp(self.executable_name, args)
-
--- a/django/db/backends/sqlite3/creation.py
+++ b/django/db/backends/sqlite3/creation.py
@ -1,36 +1,38 @@
 import os
 import sys
+
 from django.db.backends.creation import BaseDatabaseCreation
 from django.utils.six.moves import input

+
 class DatabaseCreation(BaseDatabaseCreation):
    # SQLite doesn't actually support most of these types, but it "does the right
    # thing" given more verbose field definitions, so leave them as is so that
    # schema inspection is more useful.
    data_types = {
-        'AutoField':                    'integer',
-        'BinaryField':                  'BLOB',
-        'BooleanField':                 'bool',
-        'CharField':                    'varchar(%(max_length)s)',
-        'CommaSeparatedIntegerField':   'varchar(%(max_length)s)',
-        'DateField':                    'date',
-        'DateTimeField':                'datetime',
-        'DecimalField':                 'decimal',
-        'FileField':                    'varchar(%(max_length)s)',
-        'FilePathField':                'varchar(%(max_length)s)',
-        'FloatField':                   'real',
-        'IntegerField':                 'integer',
-        'BigIntegerField':              'bigint',
-        'IPAddressField':               'char(15)',
-        'GenericIPAddressField':        'char(39)',
-        'NullBooleanField':             'bool',
-        'OneToOneField':                'integer',
-        'PositiveIntegerField':         'integer unsigned',
-        'PositiveSmallIntegerField':    'smallint unsigned',
-        'SlugField':                    'varchar(%(max_length)s)',
-        'SmallIntegerField':            'smallint',
-        'TextField':                    'text',
-        'TimeField':                    'time',
+        'AutoField': 'integer',
+        'BinaryField': 'BLOB',
+        'BooleanField': 'bool',
+        'CharField': 'varchar(%(max_length)s)',
+        'CommaSeparatedIntegerField': 'varchar(%(max_length)s)',
+        'DateField': 'date',
+        'DateTimeField': 'datetime',
+        'DecimalField': 'decimal',
+        'FileField': 'varchar(%(max_length)s)',
+        'FilePathField': 'varchar(%(max_length)s)',
+        'FloatField': 'real',
+        'IntegerField': 'integer',
+        'BigIntegerField': 'bigint',
+        'IPAddressField': 'char(15)',
+        'GenericIPAddressField': 'char(39)',
+        'NullBooleanField': 'bool',
+        'OneToOneField': 'integer',
+        'PositiveIntegerField': 'integer unsigned',
+        'PositiveSmallIntegerField': 'smallint unsigned',
+        'SlugField': 'varchar(%(max_length)s)',
+        'SmallIntegerField': 'smallint',
+        'TextField': 'text',
+        'TimeField': 'time',
    }

    def sql_for_pending_references(self, model, style, pending_references):
@ -80,7 +82,6 @@ class DatabaseCreation(BaseDatabaseCreation):
        SQLite since the databases will be distinct despite having the same
        TEST_NAME. See http://www.sqlite.org/inmemorydb.html
        """
-        settings_dict = self.connection.settings_dict
        test_dbname = self._get_test_db_name()
        sig = [self.connection.settings_dict['NAME']]
        if test_dbname == ':memory:':
--- a/django/db/backends/sqlite3/introspection.py
+++ b/django/db/backends/sqlite3/introspection.py
@ -1,8 +1,11 @@
 import re
+
 from django.db.backends import BaseDatabaseIntrospection, FieldInfo

+
 field_size_re = re.compile(r'^\s*(?:var)?char\s*\(\s*(\d+)\s*\)\s*$')

+
 def get_field_size(name):
    """ Extract the size number from a "varchar(11)" type name """
    m = field_size_re.search(name)
@ -46,6 +49,7 @@ class FlexibleFieldLookupDict(object):
                return ('CharField', {'max_length': size})
            raise KeyError

+
 class DatabaseIntrospection(BaseDatabaseIntrospection):
    data_types_reverse = FlexibleFieldLookupDict()

@ -76,7 +80,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
        # Schema for this table
        cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
        results = cursor.fetchone()[0].strip()
-        results = results[results.index('(')+1:results.rindex(')')]
+        results = results[results.index('(') + 1:results.rindex(')')]

        # Walk through and look for references to other tables. SQLite doesn't
        # really have enforced references, but since it echoes out the SQL used
@ -96,8 +100,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
            result = cursor.fetchall()[0]
            other_table_results = result[0].strip()
            li, ri = other_table_results.index('('), other_table_results.rindex(')')
-            other_table_results = other_table_results[li+1:ri]
-
+            other_table_results = other_table_results[li + 1:ri]

            for other_index, other_desc in enumerate(other_table_results.split(',')):
                other_desc = other_desc.strip()
@ -121,7 +124,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
        # Schema for this table
        cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
        results = cursor.fetchone()[0].strip()
-        results = results[results.index('(')+1:results.rindex(')')]
+        results = results[results.index('(') + 1:results.rindex(')')]

        # Walk through and look for references to other tables. SQLite doesn't
        # really have enforced references, but since it echoes out the SQL used
@ -166,7 +169,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
        # Don't use PRAGMA because that causes issues with some transactions
        cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
        results = cursor.fetchone()[0].strip()
-        results = results[results.index('(')+1:results.rindex(')')]
+        results = results[results.index('(') + 1:results.rindex(')')]
        for field_desc in results.split(','):
            field_desc = field_desc.strip()
            m = re.search('"(.*)".*PRIMARY KEY$', field_desc)
--- a/django/db/backends/util.py
+++ b/django/db/backends/util.py
@ -85,20 +85,25 @@ class CursorDebugWrapper(CursorWrapper):
 def typecast_date(s):
    return datetime.date(*map(int, s.split('-'))) if s else None # returns None if s is null

+
 def typecast_time(s): # does NOT store time zone information
-    if not s: return None
+    if not s:
+        return None
    hour, minutes, seconds = s.split(':')
    if '.' in seconds: # check whether seconds have a fractional part
        seconds, microseconds = seconds.split('.')
    else:
        microseconds = '0'
-    return datetime.time(int(hour), int(minutes), int(seconds), int(float('.'+microseconds) * 1000000))
+    return datetime.time(int(hour), int(minutes), int(seconds), int(float('.' + microseconds) * 1000000))
+

 def typecast_timestamp(s): # does NOT store time zone information
    # "2005-07-29 15:48:00.590358-05"
    # "2005-07-29 09:56:00-05"
-    if not s: return None
-    if not ' ' in s: return typecast_date(s)
+    if not s:
+        return None
+    if not ' ' in s:
+        return typecast_date(s)
    d, t = s.split()
    # Extract timezone information, if it exists. Currently we just throw
    # it away, but in the future we may make use of it.
@ -122,11 +127,13 @@ def typecast_timestamp(s): # does NOT store time zone information
        int(times[0]), int(times[1]), int(seconds),
        int((microseconds + '000000')[:6]), tzinfo)

+
 def typecast_decimal(s):
    if s is None or s == '':
        return None
    return decimal.Decimal(s)

+
 ###############################################
 # Converters from Python to database (string) #
 ###############################################
@ -136,6 +143,7 @@ def rev_typecast_decimal(d):
        return None
    return str(d)

+
 def truncate_name(name, length=None, hash_len=4):
    """Shortens a string to a repeatable mangled version with the given length.
    """
@ -143,7 +151,8 @@ def truncate_name(name, length=None, hash_len=4):
        return name

    hsh = hashlib.md5(force_bytes(name)).hexdigest()[:hash_len]
-    return '%s%s' % (name[:length-hash_len], hsh)
+    return '%s%s' % (name[:length - hash_len], hsh)
+

 def format_number(value, max_digits, decimal_places):
    """
--- a/django/db/models/init.py
+++ b/django/db/models/init.py
@ -26,6 +26,7 @@ def permalink(func):
        (viewname, viewargs, viewkwargs)
    """
    from django.core.urlresolvers import reverse
+
    @wraps(func)
    def inner(*args, **kwargs):
        bits = func(*args, **kwargs)
--- a/django/db/models/aggregates.py
+++ b/django/db/models/aggregates.py
@ -3,6 +3,7 @@ Classes to represent the definitions of aggregate functions.
 """
 from django.db.models.constants import LOOKUP_SEP

+
 def refs_aggregate(lookup_parts, aggregates):
    """
    A little helper method to check if the lookup_parts contains references
@ -15,6 +16,7 @@ def refs_aggregate(lookup_parts, aggregates):
            return True
    return False

+
 class Aggregate(object):
    """
    Default Aggregate definition.
@ -58,23 +60,30 @@ class Aggregate(object):
        aggregate = klass(col, source=source, is_summary=is_summary, **self.extra)
        query.aggregates[alias] = aggregate

+
 class Avg(Aggregate):
    name = 'Avg'

+
 class Count(Aggregate):
    name = 'Count'

+
 class Max(Aggregate):
    name = 'Max'

+
 class Min(Aggregate):
    name = 'Min'

+
 class StdDev(Aggregate):
    name = 'StdDev'

+
 class Sum(Aggregate):
    name = 'Sum'

+
 class Variance(Aggregate):
    name = 'Variance'
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@ -19,6 +19,7 @@ from django.db.models.query_utils import DeferredAttribute, deferred_class_facto
 from django.db.models.deletion import Collector
 from django.db.models.options import Options
 from django.db.models import signals
+from django.db.models.loading import register_models, get_model, MODELS_MODULE_NAME
 from django.utils.translation import ugettext_lazy as _
 from django.utils.functional import curry
 from django.utils.encoding import force_str, force_text
@ -85,10 +86,22 @@ class ModelBase(type):
        base_meta = getattr(new_class, '_meta', None)

        if getattr(meta, 'app_label', None) is None:
-            # Figure out the app_label by looking one level up.
+            # Figure out the app_label by looking one level up from the package
+            # or module named 'models'. If no such package or module exists,
+            # fall back to looking one level up from the module this model is
+            # defined in.
+
            # For 'django.contrib.sites.models', this would be 'sites'.
+            # For 'geo.models.places' this would be 'geo'.
+
            model_module = sys.modules[new_class.__module__]
-            kwargs = {"app_label": model_module.__name__.split('.')[-2]}
+            package_components = model_module.__name__.split('.')
+            package_components.reverse()  # find the last occurrence of 'models'
+            try:
+                app_label_index = package_components.index(MODELS_MODULE_NAME) + 1
+            except ValueError:
+                app_label_index = 1
+            kwargs = {"app_label": package_components[app_label_index]}
        else:
            kwargs = {}

@ -225,9 +238,9 @@ class ModelBase(type):
            # class
            for field in base._meta.virtual_fields:
                if base._meta.abstract and field.name in field_names:
-                    raise FieldError('Local field %r in class %r clashes '\
-                                     'with field of similar name from '\
-                                     'abstract base class %r' % \
+                    raise FieldError('Local field %r in class %r clashes '
+                                     'with field of similar name from '
+                                     'abstract base class %r' %
                                        (field.name, name, base.__name__))
                new_class.add_to_class(field.name, copy.deepcopy(field))

@ -1007,8 +1020,6 @@ def get_absolute_url(opts, func, self, *args, **kwargs):
 # MISC #
 ########

-class Empty(object):
-    pass

 def simple_class_factory(model, attrs):
    """
@ -1016,6 +1027,7 @@ def simple_class_factory(model, attrs):
    """
    return model

+
 def model_unpickle(model_id, attrs, factory):
    """
    Used to unpickle Model subclasses with deferred fields.
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@ -4,6 +4,7 @@ from django.db.models.aggregates import refs_aggregate
 from django.db.models.constants import LOOKUP_SEP
 from django.utils import tree

+
 class ExpressionNode(tree.Node):
    """
    Base class for all query expressions.
@ -128,6 +129,7 @@ class ExpressionNode(tree.Node):
            "Use .bitand() and .bitor() for bitwise logical operations."
        )

+
 class F(ExpressionNode):
    """
    An expression representing the value of the given field.
@ -147,6 +149,7 @@ class F(ExpressionNode):
    def evaluate(self, evaluator, qn, connection):
        return evaluator.evaluate_leaf(self, qn, connection)

+
 class DateModifierNode(ExpressionNode):
    """
    Node that implements the following syntax:
--- a/django/db/models/fields/init.py
+++ b/django/db/models/fields/init.py
@ -1,5 +1,6 @@
 from __future__ import unicode_literals

+import collections
 import copy
 import datetime
 import decimal
@ -17,7 +18,6 @@ from django.core import exceptions, validators
 from django.utils.datastructures import DictWrapper
 from django.utils.dateparse import parse_date, parse_datetime, parse_time
 from django.utils.functional import curry, total_ordering
-from django.utils.itercompat import is_iterator
 from django.utils.text import capfirst
 from django.utils import timezone
 from django.utils.translation import ugettext_lazy as _
@ -25,9 +25,11 @@ from django.utils.encoding import smart_text, force_text, force_bytes
 from django.utils.ipv6 import clean_ipv6_address
 from django.utils import six

+
 class Empty(object):
    pass

+
 class NOT_PROVIDED:
    pass

@ -35,12 +37,15 @@ class NOT_PROVIDED:
 # of most "choices" lists.
 BLANK_CHOICE_DASH = [("", "---------")]

+
 def _load_field(app_label, model_name, field_name):
    return get_model(app_label, model_name)._meta.get_field_by_name(field_name)[0]

+
 class FieldDoesNotExist(Exception):
    pass

+
 # A guide to Field parameters:
 #
 #   * name:      The name of the field specifed in the model.
@ -61,6 +66,7 @@ def _empty(of_cls):
    new.__class__ = of_cls
    return new

+
@total_ordering
 class Field(object):
    """Base class for all field types"""
@ -464,12 +470,12 @@ class Field(object):
        if hasattr(value, '_prepare'):
            return value._prepare()

-        if lookup_type in (
-                'iexact', 'contains', 'icontains',
-                'startswith', 'istartswith', 'endswith', 'iendswith',
-                'month', 'day', 'week_day', 'hour', 'minute', 'second',
-                'isnull', 'search', 'regex', 'iregex',
-            ):
+        if lookup_type in {
+            'iexact', 'contains', 'icontains',
+            'startswith', 'istartswith', 'endswith', 'iendswith',
+            'month', 'day', 'week_day', 'hour', 'minute', 'second',
+            'isnull', 'search', 'regex', 'iregex',
+        }:
            return value
        elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte'):
            return self.get_prep_value(value)
@ -599,7 +605,7 @@ class Field(object):
        return bound_field_class(self, fieldmapping, original)

    def _get_choices(self):
-        if is_iterator(self._choices):
+        if isinstance(self._choices, collections.Iterator):
            choices, self._choices = tee(self._choices)
            return choices
        else:
@ -613,7 +619,7 @@ class Field(object):
            if isinstance(value, (list, tuple)):
                flat.extend(value)
            else:
-                flat.append((choice,value))
+                flat.append((choice, value))
        return flat
    flatchoices = property(_get_flatchoices)

@ -732,6 +738,7 @@ class AutoField(Field):
    def formfield(self, **kwargs):
        return None

+
 class BooleanField(Field):
    empty_strings_allowed = False
    default_error_messages = {
@ -786,13 +793,13 @@ class BooleanField(Field):
        if self.choices:
            include_blank = (self.null or
                             not (self.has_default() or 'initial' in kwargs))
-            defaults = {'choices': self.get_choices(
-                                       include_blank=include_blank)}
+            defaults = {'choices': self.get_choices(include_blank=include_blank)}
        else:
            defaults = {'form_class': forms.BooleanField}
        defaults.update(kwargs)
        return super(BooleanField, self).formfield(**defaults)

+
 class CharField(Field):
    description = _("String (up to %(max_length)s)")

@ -819,6 +826,7 @@ class CharField(Field):
        defaults.update(kwargs)
        return super(CharField, self).formfield(**defaults)

+
 # TODO: Maybe move this into contrib, because it's specialized.
 class CommaSeparatedIntegerField(CharField):
    default_validators = [validators.validate_comma_separated_integer_list]
@ -833,6 +841,7 @@ class CommaSeparatedIntegerField(CharField):
        defaults.update(kwargs)
        return super(CommaSeparatedIntegerField, self).formfield(**defaults)

+
 class DateField(Field):
    empty_strings_allowed = False
    default_error_messages = {
@ -905,7 +914,7 @@ class DateField(Field):
            return super(DateField, self).pre_save(model_instance, add)

    def contribute_to_class(self, cls, name):
-        super(DateField,self).contribute_to_class(cls, name)
+        super(DateField, self).contribute_to_class(cls, name)
        if not self.null:
            setattr(cls, 'get_next_by_%s' % self.name,
                curry(cls._get_next_or_previous_by_FIELD, field=self,
@ -939,6 +948,7 @@ class DateField(Field):
        defaults.update(kwargs)
        return super(DateField, self).formfield(**defaults)

+
 class DateTimeField(DateField):
    empty_strings_allowed = False
    default_error_messages = {
@ -1045,6 +1055,7 @@ class DateTimeField(DateField):
        defaults.update(kwargs)
        return super(DateTimeField, self).formfield(**defaults)

+
 class DecimalField(Field):
    empty_strings_allowed = False
    default_error_messages = {
@ -1116,6 +1127,7 @@ class DecimalField(Field):
        defaults.update(kwargs)
        return super(DecimalField, self).formfield(**defaults)

+
 class EmailField(CharField):
    default_validators = [validators.validate_email]
    description = _("Email address")
@ -1142,13 +1154,14 @@ class EmailField(CharField):
        defaults.update(kwargs)
        return super(EmailField, self).formfield(**defaults)

+
 class FilePathField(Field):
    description = _("File path")

    def __init__(self, verbose_name=None, name=None, path='', match=None,
                 recursive=False, allow_files=True, allow_folders=False, **kwargs):
        self.path, self.match, self.recursive = path, match, recursive
-        self.allow_files, self.allow_folders =  allow_files, allow_folders
+        self.allow_files, self.allow_folders = allow_files, allow_folders
        kwargs['max_length'] = kwargs.get('max_length', 100)
        Field.__init__(self, verbose_name, name, **kwargs)

@ -1183,6 +1196,7 @@ class FilePathField(Field):
    def get_internal_type(self):
        return "FilePathField"

+
 class FloatField(Field):
    empty_strings_allowed = False
    default_error_messages = {
@ -1215,6 +1229,7 @@ class FloatField(Field):
        defaults.update(kwargs)
        return super(FloatField, self).formfield(**defaults)

+
 class IntegerField(Field):
    empty_strings_allowed = False
    default_error_messages = {
@ -1253,6 +1268,7 @@ class IntegerField(Field):
        defaults.update(kwargs)
        return super(IntegerField, self).formfield(**defaults)

+
 class BigIntegerField(IntegerField):
    empty_strings_allowed = False
    description = _("Big (8 byte) integer")
@ -1267,6 +1283,7 @@ class BigIntegerField(IntegerField):
        defaults.update(kwargs)
        return super(BigIntegerField, self).formfield(**defaults)

+
 class IPAddressField(Field):
    empty_strings_allowed = False
    description = _("IPv4 address")
@ -1288,6 +1305,7 @@ class IPAddressField(Field):
        defaults.update(kwargs)
        return super(IPAddressField, self).formfield(**defaults)

+
 class GenericIPAddressField(Field):
    empty_strings_allowed = True
    description = _("IP address")
@ -1336,7 +1354,10 @@ class GenericIPAddressField(Field):
        return value

    def formfield(self, **kwargs):
-        defaults = {'form_class': forms.GenericIPAddressField}
+        defaults = {
+            'protocol': self.protocol,
+            'form_class': forms.GenericIPAddressField,
+        }
        defaults.update(kwargs)
        return super(GenericIPAddressField, self).formfield(**defaults)

@ -1403,6 +1424,7 @@ class NullBooleanField(Field):
        defaults.update(kwargs)
        return super(NullBooleanField, self).formfield(**defaults)

+
 class PositiveIntegerField(IntegerField):
    description = _("Positive integer")

@ -1414,6 +1436,7 @@ class PositiveIntegerField(IntegerField):
        defaults.update(kwargs)
        return super(PositiveIntegerField, self).formfield(**defaults)

+
 class PositiveSmallIntegerField(IntegerField):
    description = _("Positive small integer")

@ -1425,6 +1448,7 @@ class PositiveSmallIntegerField(IntegerField):
        defaults.update(kwargs)
        return super(PositiveSmallIntegerField, self).formfield(**defaults)

+
 class SlugField(CharField):
    default_validators = [validators.validate_slug]
    description = _("Slug (up to %(max_length)s)")
@ -1454,12 +1478,14 @@ class SlugField(CharField):
        defaults.update(kwargs)
        return super(SlugField, self).formfield(**defaults)

+
 class SmallIntegerField(IntegerField):
    description = _("Small integer")

    def get_internal_type(self):
        return "SmallIntegerField"

+
 class TextField(Field):
    description = _("Text")

@ -1476,6 +1502,7 @@ class TextField(Field):
        defaults.update(kwargs)
        return super(TextField, self).formfield(**defaults)

+
 class TimeField(Field):
    empty_strings_allowed = False
    default_error_messages = {
@ -1559,6 +1586,7 @@ class TimeField(Field):
        defaults.update(kwargs)
        return super(TimeField, self).formfield(**defaults)

+
 class URLField(CharField):
    default_validators = [validators.URLValidator()]
    description = _("URL")
@ -1582,6 +1610,7 @@ class URLField(CharField):
        defaults.update(kwargs)
        return super(URLField, self).formfield(**defaults)

+
 class BinaryField(Field):
    description = _("Raw binary data")
    empty_values = [None, b'']
--- a/django/db/models/fields/files.py
+++ b/django/db/models/fields/files.py
@ -11,6 +11,7 @@ from django.utils.encoding import force_str, force_text
 from django.utils import six
 from django.utils.translation import ugettext_lazy as _

+
 class FieldFile(File):
    def __init__(self, instance, field, name):
        super(FieldFile, self).__init__(None, name)
@ -135,6 +136,7 @@ class FieldFile(File):
        # be restored later, by FileDescriptor below.
        return {'name': self.name, 'closed': False, '_committed': True, '_file': None}

+
 class FileDescriptor(object):
    """
    The descriptor for the file attribute on the model instance. Returns a
@ -205,6 +207,7 @@ class FileDescriptor(object):
    def __set__(self, instance, value):
        instance.__dict__[self.field.name] = value

+
 class FileField(Field):

    # The class to wrap instance attributes in. Accessing the file object off
@ -300,6 +303,7 @@ class FileField(Field):
        defaults.update(kwargs)
        return super(FileField, self).formfield(**defaults)

+
 class ImageFileDescriptor(FileDescriptor):
    """
    Just like the FileDescriptor, but for ImageFields. The only difference is
@ -321,14 +325,15 @@ class ImageFileDescriptor(FileDescriptor):
        if previous_file is not None:
            self.field.update_dimension_fields(instance, force=True)

-class ImageFieldFile(ImageFile, FieldFile):

+class ImageFieldFile(ImageFile, FieldFile):
    def delete(self, save=True):
        # Clear the image dimensions cache
        if hasattr(self, '_dimensions_cache'):
            del self._dimensions_cache
        super(ImageFieldFile, self).delete(save)

+
 class ImageField(FileField):
    attr_class = ImageFieldFile
    descriptor_class = ImageFileDescriptor
--- a/django/db/models/fields/proxy.py
+++ b/django/db/models/fields/proxy.py
@ -5,6 +5,7 @@ have the same attributes as fields sometimes (avoids a lot of special casing).

 from django.db.models import fields

+
 class OrderWrt(fields.IntegerField):
    """
    A proxy for the _order database field that is used when
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@ -211,7 +211,7 @@ class SingleRelatedObjectDescriptor(six.with_metaclass(RenameRelatedObjectDescri

        # If null=True, we can assign null here, but otherwise the value needs
        # to be an instance of the related class.
-        if value is None and self.related.field.null == False:
+        if value is None and self.related.field.null is False:
            raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' %
                                (instance._meta.object_name, self.related.get_accessor_name()))
        elif value is not None and not isinstance(value, self.related.model):
@ -310,7 +310,7 @@ class ReverseSingleRelatedObjectDescriptor(six.with_metaclass(RenameRelatedObjec
    def __set__(self, instance, value):
        # If null=True, we can assign null here, but otherwise the value needs
        # to be an instance of the related class.
-        if value is None and self.field.null == False:
+        if value is None and self.field.null is False:
            raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' %
                                (instance._meta.object_name, self.field.name))
        elif value is not None and not isinstance(value, self.field.rel.to):
@ -395,7 +395,7 @@ class ForeignRelatedObjectsDescriptor(object):
            def __init__(self, instance):
                super(RelatedManager, self).__init__()
                self.instance = instance
-                self.core_filters= {'%s__exact' % rel_field.name: instance}
+                self.core_filters = {'%s__exact' % rel_field.name: instance}
                self.model = rel_model

            def get_queryset(self):
@ -510,7 +510,6 @@ def create_many_related_manager(superclass, rel):
                                 "a many-to-many relationship can be used." %
                                 instance.__class__.__name__)

-
        def _get_fk_val(self, obj, field_name):
            """
            Returns the correct value for this relationship's foreign key. This
@ -821,6 +820,7 @@ class ReverseManyRelatedObjectsDescriptor(object):
        manager.clear()
        manager.add(*value)

+
 class ForeignObjectRel(object):
    def __init__(self, field, to, related_name=None, limit_choices_to=None,
                 parent_link=False, on_delete=None, related_query_name=None):
@ -858,6 +858,7 @@ class ForeignObjectRel(object):
        # example custom multicolumn joins currently have no remote field).
        self.field_name = None

+
 class ManyToOneRel(ForeignObjectRel):
    def __init__(self, field, to, field_name, related_name=None, limit_choices_to=None,
                 parent_link=False, on_delete=None, related_query_name=None):
@ -1125,7 +1126,7 @@ class ForeignKey(ForeignObject):
    def __init__(self, to, to_field=None, rel_class=ManyToOneRel,
                 db_constraint=True, **kwargs):
        try:
-            to_name = to._meta.object_name.lower()
+            to._meta.object_name.lower()
        except AttributeError:  # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
            assert isinstance(to, six.string_types), "%s(%r) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string %r" % (self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT)
        else:
@ -1162,7 +1163,6 @@ class ForeignKey(ForeignObject):
        if self.rel.on_delete is not CASCADE:
            kwargs['on_delete'] = self.rel.on_delete
        # Rel needs more work.
-        rel = self.rel
        if self.rel.field_name:
            kwargs['to_field'] = self.rel.field_name
        if isinstance(self.rel.to, six.string_types):
@ -1193,8 +1193,8 @@ class ForeignKey(ForeignObject):

        using = router.db_for_read(model_instance.__class__, instance=model_instance)
        qs = self.rel.to._default_manager.using(using).filter(
-                **{self.rel.field_name: value}
-             )
+          **{self.rel.field_name: value}
+         )
        qs = qs.complex_filter(self.rel.limit_choices_to)
        if not qs.exists():
            raise exceptions.ValidationError(
@ -1222,7 +1222,7 @@ class ForeignKey(ForeignObject):
        return field_default

    def get_db_prep_save(self, value, connection):
-        if value == '' or value == None:
+        if value == '' or value is None:
            return None
        else:
            return self.related_field.get_db_prep_save(value,
@ -1393,7 +1393,6 @@ class ManyToManyField(RelatedField):
        if "help_text" in kwargs:
            del kwargs['help_text']
        # Rel needs more work.
-        rel = self.rel
        if isinstance(self.rel.to, six.string_types):
            kwargs['to'] = self.rel.to
        else:
--- a/django/db/models/fields/subclassing.py
+++ b/django/db/models/fields/subclassing.py
@ -7,6 +7,7 @@ to_python() and the other necessary methods and everything will work
 seamlessly.
 """

+
 class SubfieldBase(type):
    """
    A metaclass for custom Field subclasses. This ensures the model's attribute
@ -19,6 +20,7 @@ class SubfieldBase(type):
        )
        return new_class

+
 class Creator(object):
    """
    A placeholder class that provides a way to set the attribute on the model.
@ -34,6 +36,7 @@ class Creator(object):
    def __set__(self, obj, value):
        obj.__dict__[self.field.name] = self.field.to_python(value)

+
 def make_contrib(superclass, func=None):
    """
    Returns a suitable contribute_to_class() method for the Field subclass.
--- a/django/db/models/loading.py
+++ b/django/db/models/loading.py
@ -15,9 +15,13 @@ import os
 __all__ = ('get_apps', 'get_app', 'get_models', 'get_model', 'register_models',
        'load_app', 'app_cache_ready')

+MODELS_MODULE_NAME = 'models'
+
+
 class UnavailableApp(Exception):
    pass

+
 def _initialize():
    """
    Returns a dictionary to be used as the initial value of the
@ -118,12 +122,12 @@ class BaseAppCache(object):
        self.nesting_level += 1
        app_module = import_module(app_name)
        try:
-            models = import_module('.models', app_name)
+            models = import_module('.' + MODELS_MODULE_NAME, app_name)
        except ImportError:
            self.nesting_level -= 1
            # If the app doesn't have a models module, we can just ignore the
            # ImportError and return no models for it.
-            if not module_has_submodule(app_module, 'models'):
+            if not module_has_submodule(app_module, MODELS_MODULE_NAME):
                return None
            # But if the app does have a models module, we need to figure out
            # whether to suppress or propagate the error. If can_postpone is
--- a/django/db/models/manager.py
+++ b/django/db/models/manager.py
@ -6,6 +6,7 @@ from django.db.models.fields import FieldDoesNotExist
 from django.utils import six
 from django.utils.deprecation import RenameMethodsBase

+
 def ensure_default_manager(sender, **kwargs):
    """
    Ensures that a Model subclass contains a default manager  and sets the
@ -153,6 +154,9 @@ class Manager(six.with_metaclass(RenameManagerMethods)):
    def get_or_create(self, **kwargs):
        return self.get_queryset().get_or_create(**kwargs)

+    def update_or_create(self, **kwargs):
+        return self.get_queryset().update_or_create(**kwargs)
+
    def create(self, **kwargs):
        return self.get_queryset().create(**kwargs)

@ -245,7 +249,7 @@ class ManagerDescriptor(object):
        self.manager = manager

    def __get__(self, instance, type=None):
-        if instance != None:
+        if instance is not None:
            raise AttributeError("Manager isn't accessible via %s instances" % type.__name__)
        return self.manager

--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@ -19,6 +19,10 @@ from django.utils.functional import partition
 from django.utils import six
 from django.utils import timezone

+# The maximum number (one less than the max to be precise) of results to fetch
+# in a get() query
+MAX_GET_RESULTS = 20
+
 # The maximum number of items to display in a QuerySet.__repr__
 REPR_OUTPUT_SIZE = 20

@ -297,6 +301,7 @@ class QuerySet(object):
        clone = self.filter(*args, **kwargs)
        if self.query.can_filter():
            clone = clone.order_by()
+        clone = clone[:MAX_GET_RESULTS + 1]
        num = len(clone)
        if num == 1:
            return clone._result_cache[0]
@ -305,8 +310,11 @@ class QuerySet(object):
                "%s matching query does not exist." %
                self.model._meta.object_name)
        raise self.model.MultipleObjectsReturned(
-            "get() returned more than one %s -- it returned %s!" %
-            (self.model._meta.object_name, num))
+            "get() returned more than one %s -- it returned %s!" % (
+                self.model._meta.object_name,
+                num if num <= MAX_GET_RESULTS else 'more than %s' % MAX_GET_RESULTS
+            )
+        )

    def create(self, **kwargs):
        """
@ -351,42 +359,89 @@ class QuerySet(object):
                if objs_with_pk:
                    self._batched_insert(objs_with_pk, fields, batch_size)
                if objs_without_pk:
-                    fields= [f for f in fields if not isinstance(f, AutoField)]
+                    fields = [f for f in fields if not isinstance(f, AutoField)]
                    self._batched_insert(objs_without_pk, fields, batch_size)

        return objs

-    def get_or_create(self, **kwargs):
+    def get_or_create(self, defaults=None, **kwargs):
        """
        Looks up an object with the given kwargs, creating one if necessary.
        Returns a tuple of (object, created), where created is a boolean
        specifying whether an object was created.
        """
-        defaults = kwargs.pop('defaults', {})
-        lookup = kwargs.copy()
-        for f in self.model._meta.fields:
-            if f.attname in lookup:
-                lookup[f.name] = lookup.pop(f.attname)
+        lookup, params, _ = self._extract_model_params(defaults, **kwargs)
        try:
            self._for_write = True
            return self.get(**lookup), False
        except self.model.DoesNotExist:
+            return self._create_object_from_params(lookup, params)
+
+    def update_or_create(self, defaults=None, **kwargs):
+        """
+        Looks up an object with the given kwargs, updating one with defaults
+        if it exists, otherwise creates a new one.
+        Returns a tuple (object, created), where created is a boolean
+        specifying whether an object was created.
+        """
+        lookup, params, filtered_defaults = self._extract_model_params(defaults, **kwargs)
+        try:
+            self._for_write = True
+            obj = self.get(**lookup)
+        except self.model.DoesNotExist:
+            obj, created = self._create_object_from_params(lookup, params)
+            if created:
+                return obj, created
+        for k, v in six.iteritems(filtered_defaults):
+            setattr(obj, k, v)
+        try:
+            sid = transaction.savepoint(using=self.db)
+            obj.save(update_fields=filtered_defaults.keys(), using=self.db)
+            transaction.savepoint_commit(sid, using=self.db)
+            return obj, False
+        except DatabaseError:
+            transaction.savepoint_rollback(sid, using=self.db)
+            six.reraise(sys.exc_info())
+
+    def _create_object_from_params(self, lookup, params):
+        """
+        Tries to create an object using passed params.
+        Used by get_or_create and update_or_create
+        """
+        try:
+            obj = self.model(**params)
+            sid = transaction.savepoint(using=self.db)
+            obj.save(force_insert=True, using=self.db)
+            transaction.savepoint_commit(sid, using=self.db)
+            return obj, True
+        except DatabaseError:
+            transaction.savepoint_rollback(sid, using=self.db)
+            exc_info = sys.exc_info()
            try:
-                params = dict((k, v) for k, v in kwargs.items() if LOOKUP_SEP not in k)
-                params.update(defaults)
-                obj = self.model(**params)
-                sid = transaction.savepoint(using=self.db)
-                obj.save(force_insert=True, using=self.db)
-                transaction.savepoint_commit(sid, using=self.db)
-                return obj, True
-            except DatabaseError:
-                transaction.savepoint_rollback(sid, using=self.db)
-                exc_info = sys.exc_info()
-                try:
-                    return self.get(**lookup), False
-                except self.model.DoesNotExist:
-                    # Re-raise the DatabaseError with its original traceback.
-                    six.reraise(*exc_info)
+                return self.get(**lookup), False
+            except self.model.DoesNotExist:
+                # Re-raise the DatabaseError with its original traceback.
+                six.reraise(*exc_info)
+
+    def _extract_model_params(self, defaults, **kwargs):
+        """
+        Prepares `lookup` (kwargs that are valid model attributes), `params`
+        (for creating a model instance) and `filtered_defaults` (defaults
+        that are valid model attributes) based on given kwargs; for use by
+        get_or_create and update_or_create.
+        """
+        defaults = defaults or {}
+        filtered_defaults = {}
+        lookup = kwargs.copy()
+        for f in self.model._meta.fields:
+            # Filter out fields that don't belongs to the model.
+            if f.attname in lookup:
+                lookup[f.name] = lookup.pop(f.attname)
+            if f.attname in defaults:
+                filtered_defaults[f.name] = defaults.pop(f.attname)
+        params = dict((k, v) for k, v in kwargs.items() if LOOKUP_SEP not in k)
+        params.update(filtered_defaults)
+        return lookup, params, filtered_defaults

    def _earliest_or_latest(self, field_name=None, direction="-"):
        """
@ -638,7 +693,7 @@ class QuerySet(object):
        obj.query.select_for_update_nowait = nowait
        return obj

-    def select_related(self, *fields, **kwargs):
+    def select_related(self, *fields):
        """
        Returns a new QuerySet instance that will select related objects.

@ -647,9 +702,6 @@ class QuerySet(object):

        If select_related(None) is called, the list is cleared.
        """
-        if kwargs:
-            raise TypeError('Unexpected keyword arguments to select_related: %s'
-                    % (list(kwargs),))
        obj = self._clone()
        if fields == (None,):
            obj.query.select_related = False
@ -821,7 +873,7 @@ class QuerySet(object):
            return
        ops = connections[self.db].ops
        batch_size = (batch_size or max(ops.bulk_batch_size(fields, objs), 1))
-        for batch in [objs[i:i+batch_size]
+        for batch in [objs[i:i + batch_size]
                      for i in range(0, len(objs), batch_size)]:
            self.model._base_manager._insert(batch, fields=fields,
                                             using=self.db)
@ -902,10 +954,12 @@ class QuerySet(object):
    # empty" result.
    value_annotation = True

+
 class InstanceCheckMeta(type):
    def __instancecheck__(self, instance):
        return instance.query.is_empty()

+
 class EmptyQuerySet(six.with_metaclass(InstanceCheckMeta)):
    """
    Marker class usable for checking if a queryset is empty by .none():
@ -915,6 +969,7 @@ class EmptyQuerySet(six.with_metaclass(InstanceCheckMeta)):
    def __init__(self, *args, **kwargs):
        raise TypeError("EmptyQuerySet can't be instantiated")

+
 class ValuesQuerySet(QuerySet):
    def __init__(self, *args, **kwargs):
        super(ValuesQuerySet, self).__init__(*args, **kwargs)
@ -1243,7 +1298,7 @@ def get_klass_info(klass, max_depth=0, cur_depth=0, requested=None,
                                                         only_load.get(o.model), reverse=True):
                next = requested[o.field.related_query_name()]
                parent = klass if issubclass(o.model, klass) else None
-                klass_info = get_klass_info(o.model, max_depth=max_depth, cur_depth=cur_depth+1,
+                klass_info = get_klass_info(o.model, max_depth=max_depth, cur_depth=cur_depth + 1,
                                            requested=next, only_load=only_load, from_parent=parent)
                reverse_related_fields.append((o.field, klass_info))
    if field_names:
@ -1254,7 +1309,7 @@ def get_klass_info(klass, max_depth=0, cur_depth=0, requested=None,
    return klass, field_names, field_count, related_fields, reverse_related_fields, pk_idx


-def get_cached_row(row, index_start, using,  klass_info, offset=0,
+def get_cached_row(row, index_start, using, klass_info, offset=0,
                   parent_data=()):
    """
    Helper function that recursively returns an object with the specified
@ -1279,11 +1334,10 @@ def get_cached_row(row, index_start, using,  klass_info, offset=0,
        return None
    klass, field_names, field_count, related_fields, reverse_related_fields, pk_idx = klass_info

-
-    fields = row[index_start : index_start + field_count]
+    fields = row[index_start:index_start + field_count]
    # If the pk column is None (or the Oracle equivalent ''), then the related
    # object must be non-existent - set the relation to None.
-    if fields[pk_idx] == None or fields[pk_idx] == '':
+    if fields[pk_idx] is None or fields[pk_idx] == '':
        obj = None
    elif field_names:
        fields = list(fields)
@ -1513,8 +1567,6 @@ def prefetch_related_objects(result_cache, related_lookups):
    if len(result_cache) == 0:
        return # nothing to do

-    model = result_cache[0].__class__
-
    # We need to be able to dynamically add to the list of prefetch_related
    # lookups that we look up (see below).  So we need some book keeping to
    # ensure we don't do duplicate work.
@ -1541,7 +1593,7 @@ def prefetch_related_objects(result_cache, related_lookups):
            if len(obj_list) == 0:
                break

-            current_lookup = LOOKUP_SEP.join(attrs[0:level+1])
+            current_lookup = LOOKUP_SEP.join(attrs[:level + 1])
            if current_lookup in done_queries:
                # Skip any prefetching, and any object preparation
                obj_list = done_queries[current_lookup]
--- a/django/db/models/query_utils.py
+++ b/django/db/models/query_utils.py
@ -30,6 +30,7 @@ class QueryWrapper(object):
    def as_sql(self, qn=None, connection=None):
        return self.data

+
 class Q(tree.Node):
    """
    Encapsulates filters as objects that can then be combined logically (using
@ -74,6 +75,7 @@ class Q(tree.Node):
                clone.children.append(child)
        return clone

+
 class DeferredAttribute(object):
    """
    A wrapper for a deferred-loading field. When the value is read from this
@ -99,8 +101,7 @@ class DeferredAttribute(object):
            try:
                f = opts.get_field_by_name(self.field_name)[0]
            except FieldDoesNotExist:
-                f = [f for f in opts.fields
-                     if f.attname == self.field_name][0]
+                f = [f for f in opts.fields if f.attname == self.field_name][0]
            name = f.name
            # Let's see if the field is part of the parent chain. If so we
            # might be able to reuse the already loaded value. Refs #18343.
@ -174,6 +175,7 @@ def select_related_descend(field, restricted, requested, load_fields, reverse=Fa
            return False
    return True

+
 # This function is needed because data descriptors must be defined on a class
 # object, not an instance, to have any effect.

--- a/django/db/models/related.py
+++ b/django/db/models/related.py
@ -10,6 +10,7 @@ PathInfo = namedtuple('PathInfo',
                      'from_opts to_opts target_fields join_field '
                      'm2m direct')

+
 class RelatedObject(object):
    def __init__(self, parent_model, model, field):
        self.parent_model = parent_model
--- a/django/db/models/sql/aggregates.py
+++ b/django/db/models/sql/aggregates.py
@ -9,6 +9,7 @@ from django.db.models.fields import IntegerField, FloatField
 ordinal_aggregate_field = IntegerField()
 computed_aggregate_field = FloatField()

+
 class Aggregate(object):
    """
    Default SQL Aggregate.
@ -93,6 +94,7 @@ class Avg(Aggregate):
    is_computed = True
    sql_function = 'AVG'

+
 class Count(Aggregate):
    is_ordinal = True
    sql_function = 'COUNT'
@ -101,12 +103,15 @@ class Count(Aggregate):
    def __init__(self, col, distinct=False, **extra):
        super(Count, self).__init__(col, distinct='DISTINCT ' if distinct else '', **extra)

+
 class Max(Aggregate):
    sql_function = 'MAX'

+
 class Min(Aggregate):
    sql_function = 'MIN'

+
 class StdDev(Aggregate):
    is_computed = True

@ -114,9 +119,11 @@ class StdDev(Aggregate):
        super(StdDev, self).__init__(col, **extra)
        self.sql_function = 'STDDEV_SAMP' if sample else 'STDDEV_POP'

+
 class Sum(Aggregate):
    sql_function = 'SUM'

+
 class Variance(Aggregate):
    is_computed = True

--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@ -688,7 +688,7 @@ class SQLCompiler(object):
                # the relation, which is always nullable.
                new_nullable = True
                table = model._meta.db_table
-                self.fill_related_selections(model._meta, table, cur_depth+1,
+                self.fill_related_selections(model._meta, table, cur_depth + 1,
                    next, restricted, new_nullable)

    def deferred_to_columns(self):
@ -750,6 +750,16 @@ class SQLCompiler(object):

                yield row

+    def has_results(self):
+        """
+        Backends (e.g. NoSQL) can override this in order to use optimized
+        versions of "query has any results."
+        """
+        # This is always executed on a query clone, so we can modify self.query
+        self.query.add_extra({'a': 1}, None, None, None, None, None)
+        self.query.set_extra_mask(['a'])
+        return bool(self.execute_sql(SINGLE))
+
    def execute_sql(self, result_type=MULTI):
        """
        Run the query against the database and returns the result(s). The
@ -915,6 +925,7 @@ class SQLDeleteCompiler(SQLCompiler):
            result.append('WHERE %s' % where)
        return ' '.join(result), tuple(params)

+
 class SQLUpdateCompiler(SQLCompiler):
    def as_sql(self):
        """
@ -1029,6 +1040,7 @@ class SQLUpdateCompiler(SQLCompiler):
        for alias in self.query.tables[1:]:
            self.query.alias_refcount[alias] = 0

+
 class SQLAggregateCompiler(SQLCompiler):
    def as_sql(self, qn=None):
        """
@ -1050,6 +1062,7 @@ class SQLAggregateCompiler(SQLCompiler):
        params = params + self.query.sub_params
        return sql, params

+
 class SQLDateCompiler(SQLCompiler):
    def results_iter(self):
        """
@ -1075,6 +1088,7 @@ class SQLDateCompiler(SQLCompiler):
                    date = date.date()
                yield date

+
 class SQLDateTimeCompiler(SQLCompiler):
    def results_iter(self):
        """
@ -1107,6 +1121,7 @@ class SQLDateTimeCompiler(SQLCompiler):
                    datetime = timezone.make_aware(datetime, self.query.tzinfo)
                yield datetime

+
 def order_modified_iter(cursor, trim, sentinel):
    """
    Yields blocks of rows from a cursor. We use this iterator in the special
--- a/django/db/models/sql/datastructures.py
+++ b/django/db/models/sql/datastructures.py
@ -3,9 +3,11 @@ Useful auxilliary data structures for query construction. Not useful outside
 the SQL domain.
 """

+
 class EmptyResultSet(Exception):
    pass

+
 class MultiJoin(Exception):
    """
    Used by join construction code to indicate the point at which a
@ -17,12 +19,10 @@ class MultiJoin(Exception):
        # The path travelled, this includes the path to the multijoin.
        self.names_with_path = path_with_names

+
 class Empty(object):
    pass

-class RawValue(object):
-    def __init__(self, value):
-        self.value = value

 class Date(object):
    """
@ -42,6 +42,7 @@ class Date(object):
            col = self.col
        return connection.ops.date_trunc_sql(self.lookup_type, col), []

+
 class DateTime(object):
    """
    Add a datetime selection column.
--- a/django/db/models/sql/expressions.py
+++ b/django/db/models/sql/expressions.py
@ -1,7 +1,9 @@
+import copy
+
 from django.core.exceptions import FieldError
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.fields import FieldDoesNotExist
-import copy
+

 class SQLEvaluator(object):
    def __init__(self, expression, query, allow_joins=True, reuse=None):
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@ -401,12 +401,10 @@ class Query(object):
    def has_results(self, using):
        q = self.clone()
        q.clear_select_clause()
-        q.add_extra({'a': 1}, None, None, None, None, None)
-        q.set_extra_mask(['a'])
        q.clear_ordering(True)
        q.set_limits(high=1)
        compiler = q.get_compiler(using=using)
-        return bool(compiler.execute_sql(SINGLE))
+        return compiler.has_results()

    def combine(self, rhs, connector):
        """
@ -615,7 +613,6 @@ class Query(object):
            for model, values in six.iteritems(seen):
                callback(target, model, values)

-
    def deferred_to_columns_cb(self, target, model, fields):
        """
        Callback used by deferred_to_columns(). The "target" parameter should
@ -627,7 +624,6 @@ class Query(object):
        for field in fields:
            target[table].add(field.column)

-
    def table_alias(self, table_name, create=False):
        """
        Returns a table alias for the given table_name and whether this is a
@ -955,7 +951,6 @@ class Query(object):
                self.unref_alias(alias)
        self.included_inherited_models = {}

-
    def add_aggregate(self, aggregate, model, alias, is_summary):
        """
        Adds a single aggregate expression to the Query
@ -1780,7 +1775,7 @@ class Query(object):
            return self._aggregate_select_cache
        elif self.aggregate_select_mask is not None:
            self._aggregate_select_cache = SortedDict([
-                (k,v) for k,v in self.aggregates.items()
+                (k, v) for k, v in self.aggregates.items()
                if k in self.aggregate_select_mask
            ])
            return self._aggregate_select_cache
@ -1793,7 +1788,7 @@ class Query(object):
            return self._extra_select_cache
        elif self.extra_select_mask is not None:
            self._extra_select_cache = SortedDict([
-                (k,v) for k,v in self.extra.items()
+                (k, v) for k, v in self.extra.items()
                if k in self.extra_select_mask
            ])
            return self._extra_select_cache
@ -1876,6 +1871,7 @@ class Query(object):
        else:
            return field.null

+
 def get_order_dir(field, default='ASC'):
    """
    Returns the field name and direction for an order specification. For
@ -1900,6 +1896,7 @@ def add_to_dict(data, key, value):
    else:
        data[key] = set([value])

+
 def is_reverse_o2o(field):
    """
    A little helper to check if the given field is reverse-o2o. The field is
@ -1907,6 +1904,7 @@ def is_reverse_o2o(field):
    """
    return not hasattr(field, 'rel') and field.field.unique

+
 def alias_diff(refcounts_before, refcounts_after):
    """
    Given the before and after copies of refcounts works out which aliases
--- a/django/db/models/sql/subqueries.py
+++ b/django/db/models/sql/subqueries.py
@ -7,7 +7,7 @@ from django.core.exceptions import FieldError
 from django.db import connections
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.fields import DateField, DateTimeField, FieldDoesNotExist
-from django.db.models.sql.constants import *
+from django.db.models.sql.constants import GET_ITERATOR_CHUNK_SIZE, SelectInfo
 from django.db.models.sql.datastructures import Date, DateTime
 from django.db.models.sql.query import Query
 from django.db.models.sql.where import AND, Constraint
@ -20,6 +20,7 @@ from django.utils import timezone
 __all__ = ['DeleteQuery', 'UpdateQuery', 'InsertQuery', 'DateQuery',
        'DateTimeQuery', 'AggregateQuery']

+
 class DeleteQuery(Query):
    """
    Delete queries are done through this class, since they are more constrained
@ -77,7 +78,9 @@ class DeleteQuery(Query):
                return
            else:
                innerq.clear_select_clause()
-                innerq.select = [SelectInfo((self.get_initial_alias(), pk.column), None)]
+                innerq.select = [
+                    SelectInfo((self.get_initial_alias(), pk.column), None)
+                ]
                values = innerq
            where = self.where_class()
            where.add((Constraint(None, pk.column, pk), 'in', values), AND)
@ -178,6 +181,7 @@ class UpdateQuery(Query):
            result.append(query)
        return result

+
 class InsertQuery(Query):
    compiler = 'SQLInsertCompiler'

@ -215,6 +219,7 @@ class InsertQuery(Query):
        self.objs = objs
        self.raw = raw

+
 class DateQuery(Query):
    """
    A DateQuery is a normal query, except that it specifically selects a single
@ -260,6 +265,7 @@ class DateQuery(Query):
    def _get_select(self, col, lookup_type):
        return Date(col, lookup_type)

+
 class DateTimeQuery(DateQuery):
    """
    A DateTimeQuery is like a DateQuery but for a datetime field. If time zone
@ -280,6 +286,7 @@ class DateTimeQuery(DateQuery):
            tzname = timezone._get_timezone_name(self.tzinfo)
        return DateTime(col, lookup_type, tzname)

+
 class AggregateQuery(Query):
    """
    An AggregateQuery takes another query as a parameter to the FROM
--- a/django/db/models/sql/where.py
+++ b/django/db/models/sql/where.py
@ -4,6 +4,7 @@ Code to manage the creation and SQL rendering of 'where' constraints.

 from __future__ import absolute_import

+import collections
 import datetime
 from itertools import repeat

@ -11,15 +12,16 @@ from django.conf import settings
 from django.db.models.fields import DateTimeField, Field
 from django.db.models.sql.datastructures import EmptyResultSet, Empty
 from django.db.models.sql.aggregates import Aggregate
-from django.utils.itercompat import is_iterator
 from django.utils.six.moves import xrange
 from django.utils import timezone
 from django.utils import tree

+
 # Connection types
 AND = 'AND'
 OR = 'OR'

+
 class EmptyShortCircuit(Exception):
    """
    Internal exception used to indicate that a "matches nothing" node should be
@ -27,6 +29,7 @@ class EmptyShortCircuit(Exception):
    """
    pass

+
 class WhereNode(tree.Node):
    """
    Used to represent the SQL where-clause.
@ -58,7 +61,7 @@ class WhereNode(tree.Node):
        if not isinstance(data, (list, tuple)):
            return data
        obj, lookup_type, value = data
-        if is_iterator(value):
+        if isinstance(value, collections.Iterator):
            # Consume any generators immediately, so that we can determine
            # emptiness and transform any non-empty values correctly.
            value = list(value)
@ -175,7 +178,7 @@ class WhereNode(tree.Node):
        """
        lvalue, lookup_type, value_annotation, params_or_value = child
        field_internal_type = lvalue.field.get_internal_type() if lvalue.field else None
-        
+
        if isinstance(lvalue, Constraint):
            try:
                lvalue, params = lvalue.process(lookup_type, params_or_value, connection)
@ -304,14 +307,15 @@ class WhereNode(tree.Node):
                clone.children.append(child)
        return clone

-class EmptyWhere(WhereNode):

+class EmptyWhere(WhereNode):
    def add(self, data, connector):
        return

    def as_sql(self, qn=None, connection=None):
        raise EmptyResultSet

+
 class EverythingNode(object):
    """
    A node that matches everything.
@ -385,6 +389,7 @@ class Constraint(object):
            new.alias, new.col, new.field = change_map[self.alias], self.col, self.field
            return new

+
 class SubqueryConstraint(object):
    def __init__(self, alias, columns, targets, query_object):
        self.alias = alias
--- a/django/db/transaction.py
+++ b/django/db/transaction.py
@ -27,6 +27,7 @@ class TransactionManagementError(Exception):
    """
    pass

+
 ################
 # Private APIs #
 ################
@ -40,6 +41,7 @@ def get_connection(using=None):
        using = DEFAULT_DB_ALIAS
    return connections[using]

+
 ###########################
 # Deprecated private APIs #
 ###########################
@ -56,6 +58,7 @@ def abort(using=None):
    """
    get_connection(using).abort()

+
 def enter_transaction_management(managed=True, using=None, forced=False):
    """
    Enters transaction management for a running thread. It must be balanced with
@ -68,6 +71,7 @@ def enter_transaction_management(managed=True, using=None, forced=False):
    """
    get_connection(using).enter_transaction_management(managed, forced)

+
 def leave_transaction_management(using=None):
    """
    Leaves transaction management for a running thread. A dirty flag is carried
@ -76,6 +80,7 @@ def leave_transaction_management(using=None):
    """
    get_connection(using).leave_transaction_management()

+
 def is_dirty(using=None):
    """
    Returns True if the current transaction requires a commit for changes to
@ -83,6 +88,7 @@ def is_dirty(using=None):
    """
    return get_connection(using).is_dirty()

+
 def set_dirty(using=None):
    """
    Sets a dirty flag for the current thread and code streak. This can be used
@ -91,6 +97,7 @@ def set_dirty(using=None):
    """
    get_connection(using).set_dirty()

+
 def set_clean(using=None):
    """
    Resets a dirty flag for the current thread and code streak. This can be used
@ -99,22 +106,27 @@ def set_clean(using=None):
    """
    get_connection(using).set_clean()

+
 def is_managed(using=None):
    warnings.warn("'is_managed' is deprecated.",
        DeprecationWarning, stacklevel=2)

+
 def managed(flag=True, using=None):
    warnings.warn("'managed' no longer serves a purpose.",
        DeprecationWarning, stacklevel=2)

+
 def commit_unless_managed(using=None):
    warnings.warn("'commit_unless_managed' is now a no-op.",
        DeprecationWarning, stacklevel=2)

+
 def rollback_unless_managed(using=None):
    warnings.warn("'rollback_unless_managed' is now a no-op.",
        DeprecationWarning, stacklevel=2)

+
 ###############
 # Public APIs #
 ###############
@ -125,24 +137,28 @@ def get_autocommit(using=None):
    """
    return get_connection(using).get_autocommit()

+
 def set_autocommit(autocommit, using=None):
    """
    Set the autocommit status of the connection.
    """
    return get_connection(using).set_autocommit(autocommit)

+
 def commit(using=None):
    """
    Commits a transaction and resets the dirty flag.
    """
    get_connection(using).commit()

+
 def rollback(using=None):
    """
    Rolls back a transaction and resets the dirty flag.
    """
    get_connection(using).rollback()

+
 def savepoint(using=None):
    """
    Creates a savepoint (if supported and required by the backend) inside the
@ -151,6 +167,7 @@ def savepoint(using=None):
    """
    return get_connection(using).savepoint()

+
 def savepoint_rollback(sid, using=None):
    """
    Rolls back the most recent savepoint (if one exists). Does nothing if
@ -158,6 +175,7 @@ def savepoint_rollback(sid, using=None):
    """
    get_connection(using).savepoint_rollback(sid)

+
 def savepoint_commit(sid, using=None):
    """
    Commits the most recent savepoint (if one exists). Does nothing if
@ -165,18 +183,21 @@ def savepoint_commit(sid, using=None):
    """
    get_connection(using).savepoint_commit(sid)

+
 def clean_savepoints(using=None):
    """
    Resets the counter used to generate unique savepoint ids in this thread.
    """
    get_connection(using).clean_savepoints()

+
 def get_rollback(using=None):
    """
    Gets the "needs rollback" flag -- for *advanced use* only.
    """
    return get_connection(using).get_rollback()

+
 def set_rollback(rollback, using=None):
    """
    Sets or unsets the "needs rollback" flag -- for *advanced use* only.
@ -191,6 +212,7 @@ def set_rollback(rollback, using=None):
    """
    return get_connection(using).set_rollback(rollback)

+
 #################################
 # Decorators / context managers #
 #################################
@ -398,6 +420,7 @@ class Transaction(object):
                return func(*args, **kwargs)
        return inner

+
 def _transaction_func(entering, exiting, using):
    """
    Takes 3 things, an entering function (what to do to start this block of
@ -436,6 +459,7 @@ def autocommit(using=None):

    return _transaction_func(entering, exiting, using)

+
 def commit_on_success(using=None):
    """
    This decorator activates commit on response. This way, if the view function
@ -466,6 +490,7 @@ def commit_on_success(using=None):

    return _transaction_func(entering, exiting, using)

+
 def commit_manually(using=None):
    """
    Decorator that activates manual transaction control. It just disables
@ -484,6 +509,7 @@ def commit_manually(using=None):

    return _transaction_func(entering, exiting, using)

+
 def commit_on_success_unless_managed(using=None, savepoint=False):
    """
    Transitory API to preserve backwards-compatibility while refactoring.
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@ -370,8 +370,14 @@ class DecimalField(IntegerField):

    def widget_attrs(self, widget):
        attrs = super(DecimalField, self).widget_attrs(widget)
-        if isinstance(widget, NumberInput) and self.decimal_places:
-            attrs['step'] = '0.%s1' % ('0' * (self.decimal_places - 1))
+        if isinstance(widget, NumberInput):
+            if self.decimal_places is not None:
+                # Use exponential notation for small values since they might
+                # be parsed as 0 otherwise. ref #20765
+                step = str(Decimal('1') / 10 ** self.decimal_places).lower()
+            else:
+                step = 'any'
+            attrs.setdefault('step', step)
        return attrs


@ -1019,7 +1025,7 @@ class MultiValueField(Field):
            if not isinstance(initial, list):
                initial = self.widget.decompress(initial)
        for field, initial, data in zip(self.fields, initial, data):
-            if field._has_changed(initial, data):
+            if field._has_changed(field.to_python(initial), data):
                return True
        return False

--- a/django/forms/forms.py
+++ b/django/forms/forms.py
@ -77,7 +77,7 @@ class BaseForm(object):
    # information. Any improvements to the form API should be made to *this*
    # class, not to the Form class.
    def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
-                 initial=None, error_class=ErrorList, label_suffix=':',
+                 initial=None, error_class=ErrorList, label_suffix=None,
                 empty_permitted=False):
        self.is_bound = data is not None or files is not None
        self.data = data or {}
@ -86,7 +86,8 @@ class BaseForm(object):
        self.prefix = prefix
        self.initial = initial or {}
        self.error_class = error_class
-        self.label_suffix = label_suffix
+        # Translators: This is the default suffix added to form field labels
+        self.label_suffix = label_suffix if label_suffix is not None else _(':')
        self.empty_permitted = empty_permitted
        self._errors = None # Stores the errors after clean() has been called.
        self._changed_data = None
@ -518,7 +519,9 @@ class BoundField(object):
        """
        contents = contents or self.label
        # Only add the suffix if the label does not end in punctuation.
-        if self.form.label_suffix and contents and contents[-1] not in ':?.!':
+        # Translators: If found as last label character, these punctuation
+        # characters will prevent the default label_suffix to be appended to the label
+        if self.form.label_suffix and contents and contents[-1] not in _(':?.!'):
            contents = format_html('{0}{1}', contents, self.form.label_suffix)
        widget = self.field.widget
        id_ = widget.attrs.get('id') or self.auto_id
--- a/django/forms/models.py
+++ b/django/forms/models.py
@ -292,7 +292,7 @@ class ModelFormMetaclass(type):

 class BaseModelForm(BaseForm):
    def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
-                 initial=None, error_class=ErrorList, label_suffix=':',
+                 initial=None, error_class=ErrorList, label_suffix=None,
                 empty_permitted=False, instance=None):
        opts = self._meta
        if opts.model is None:
--- a/django/forms/util.py
+++ b/django/forms/util.py
@ -1,5 +1,7 @@
 from __future__ import unicode_literals

+import warnings
+
 from django.conf import settings
 from django.utils.html import format_html, format_html_join
 from django.utils.encoding import force_text, python_2_unicode_compatible
@ -21,6 +23,11 @@ def flatatt(attrs):

    The result is passed through 'mark_safe'.
    """
+    if [v for v in attrs.values() if v is True or v is False]:
+        warnings.warn(
+            'The meaning of boolean values for widget attributes will change in Django 1.8',
+            DeprecationWarning
+        )
    return format_html_join('', ' {0}="{1}"', sorted(attrs.items()))

@python_2_unicode_compatible
--- a/Show More
+++ b/Show More