Fixed #17125 -- Made it possible to change a `RegexField`'s regular expression validator after it has been initialized. Thanks to Claude Paroz for the report and patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17076 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/forms/fields.py

@@ -442,10 +442,21 @@ class RegexField(CharField):
             error_messages['invalid'] = error_message
             kwargs['error_messages'] = error_messages
         super(RegexField, self).__init__(max_length, min_length, *args, **kwargs)
+        self._set_regex(regex)
+
+    def _get_regex(self):
+        return self._regex
+
+    def _set_regex(self, regex):
         if isinstance(regex, basestring):
             regex = re.compile(regex)
-        self.regex = regex
-        self.validators.append(validators.RegexValidator(regex=regex))
+        self._regex = regex
+        if hasattr(self, '_regex_validator') and self._regex_validator in self.validators:
+            self.validators.remove(self._regex_validator)
+        self._regex_validator = validators.RegexValidator(regex=regex)
+        self.validators.append(self._regex_validator)
+
+    regex = property(_get_regex, _set_regex)
 
 class EmailField(CharField):
     default_error_messages = {

tests/regressiontests/forms/tests/fields.py

@@ -493,6 +493,12 @@ class FieldsTests(SimpleTestCase):
         self.assertRaisesMessage(ValidationError, "[u'Ensure this value has at most 10 characters (it has 11).']", f.clean, '12345678901')
         self.assertRaisesMessage(ValidationError, "[u'Enter a valid value.']", f.clean, '12345a')
 
+    def test_change_regex_after_init(self):
+        f = RegexField('^[a-z]+$')
+        f.regex = '^\d+$'
+        self.assertEqual(u'1234', f.clean('1234'))
+        self.assertRaisesMessage(ValidationError, "[u'Enter a valid value.']", f.clean, 'abcd')
+
     # EmailField ##################################################################
 
     def test_emailfield_1(self):