Ticket #12858: django_datefield_has_changed_fix.diff

django/forms/widgets.py

@@ -11 +11 @@
 from django.utils.encoding import StrAndUnicode, force_unicode
 from django.utils.safestring import mark_safe
 from django.utils import datetime_safe, formats
-from datetime import time
+import time
+import datetime
+from django.utils.formats import get_format
 from util import flatatt
 from urlparse import urljoin
 
@@ -309 +311 @@
         return super(DateInput, self).render(name, value, attrs)
 
     def _has_changed(self, initial, data):
+        # if our field has show_hidden_initial == True, initial will be a string formatted by
+        # HiddenInput using formats.localize_input, which is not necessarily the format used for
+        # this DateInput widget. Attempt to convert it.
+        try:
+            initial = datetime.date(*time.strptime(initial, get_format('DATE_INPUT_FORMATS')[0])[:3])
+        except (TypeError, ValueError):
+            pass
         return super(DateInput, self)._has_changed(self._format_value(initial), data)
 
 class DateTimeInput(Input):