[1.9.x] Fixed #25942 -- Fixed TypedChoiceField.has_changed with nullable field

This fixes a regression introduced by 871440361.
Backport of d91cc25a2a from master.

1 files changed, 5 insertions, 6 deletions

diff --git a/django/forms/fields.py b/django/forms/fields.py
index 85e7219cd4..d2ae133486 100644
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@@ -191,17 +191,16 @@ class Field(six.with_metaclass(RenameFieldMethods, object)):
         """
         Return True if data differs from initial.
         """
-        # For purposes of seeing whether something has changed, None is
-        # the same as an empty string, if the data or initial value we get
-        # is None, replace it w/ ''.
-        initial_value = initial if initial is not None else ''
         try:
             data = self.to_python(data)
             if hasattr(self, '_coerce'):
-                data = self._coerce(data)
-                initial_value = self._coerce(initial_value)
+                return self._coerce(data) != self._coerce(initial)
         except ValidationError:
             return True
+        # For purposes of seeing whether something has changed, None is
+        # the same as an empty string, if the data or initial value we get
+        # is None, replace it with ''.
+        initial_value = initial if initial is not None else ''
         data_value = data if data is not None else ''
         return initial_value != data_value