[1.7.x] Fixed #22255 -- Added support for specifying re flags in RegexValidator

Backport of 4d0c5f61 from master.

django/core/validators.py

@@ -21,8 +21,9 @@ class RegexValidator(object):
     message = _('Enter a valid value.')
     code = 'invalid'
     inverse_match = False
+    flags = 0
 
-    def __init__(self, regex=None, message=None, code=None, inverse_match=None):
+    def __init__(self, regex=None, message=None, code=None, inverse_match=None, flags=None):
         if regex is not None:
             self.regex = regex
         if message is not None:
@@ -31,10 +32,14 @@ class RegexValidator(object):
             self.code = code
         if inverse_match is not None:
             self.inverse_match = inverse_match
+        if flags is not None:
+            self.flags = flags
+        if self.flags and not isinstance(self.regex, six.string_types):
+            raise TypeError("If the flags are set, regex must be a regular expression string.")
 
         # Compile the regex if it was not passed pre-compiled.
         if isinstance(self.regex, six.string_types):
-            self.regex = re.compile(self.regex)
+            self.regex = re.compile(self.regex, self.flags)
 
     def __call__(self, value):
         """

docs/ref/validators.txt

@@ -59,13 +59,16 @@ to, or in lieu of custom ``field.clean()`` methods.
 
 ``RegexValidator``
 ------------------
-.. class:: RegexValidator([regex=None, message=None, code=None, inverse_match=None])
+.. class:: RegexValidator([regex=None, message=None, code=None, inverse_match=None, flags=0])
 
     :param regex: If not ``None``, overrides :attr:`regex`. Can be a regular
         expression string or a pre-compiled regular expression.
     :param message: If not ``None``, overrides :attr:`.message`.
     :param code: If not ``None``, overrides :attr:`code`.
     :param inverse_match: If not ``None``, overrides :attr:`inverse_match`.
+    :param flags: If not ``None``, overrides :attr:`flags`. In that case,
+        :attr:`regex` must be a regular expression string, or
+        :exc:`~exceptions.TypeError` is raised.
 
     .. attribute:: regex
 
@@ -93,6 +96,15 @@ to, or in lieu of custom ``field.clean()`` methods.
 
         The match mode for :attr:`regex`. Defaults to ``False``.
 
+    .. attribute:: flags
+
+        .. versionadded:: 1.7
+
+        The flags used when compiling the regular expression string :attr:`regex`.
+        If :attr:`regex` is a pre-compiled regular expression, and :attr:`flags` is overridden,
+        :exc:`~exceptions.TypeError` is raised.
+        Defaults to `0`.
+
 ``URLValidator``
 ----------------
 .. class:: URLValidator([schemes=None, regex=None, message=None, code=None])

docs/releases/1.7.txt

@@ -795,11 +795,15 @@ Tests
 Validators
 ^^^^^^^^^^
 
-* :class:`~django.core.validators.RegexValidator` now accepts an optional
-  Boolean :attr:`~django.core.validators.RegexValidator.inverse_match` argument
-  which determines if the :exc:`~django.core.exceptions.ValidationError` should
+* :class:`~django.core.validators.RegexValidator` now accepts the optional
+  :attr:`~django.core.validators.RegexValidator.flags` and
+  Boolean :attr:`~django.core.validators.RegexValidator.inverse_match` arguments.
+  The :attr:`~django.core.validators.RegexValidator.inverse_match` attribute
+  determines if the :exc:`~django.core.exceptions.ValidationError` should
   be raised when the regular expression pattern matches (``True``) or does not
-  match (``False``, by default) the provided ``value``.
+  match (``False``, by default) the provided ``value``. The
+  :attr:`~django.core.validators.RegexValidator.flags` attribute sets the flags
+  used when compiling a regular expression string.
 
 * :class:`~django.core.validators.URLValidator` now accepts an optional
   ``schemes`` argument which allows customization of the accepted URI schemes
@@ -1191,6 +1195,13 @@ Miscellaneous
   a relation from the related object back to the content type for filtering,
   ordering and other query operations.
 
+* When a model field's :attr:`~django.db.models.Field.validators` contains
+  a :class:`~django.core.validators.RegexValidator`, the regular expression
+  must now be passed as a regular expression string. You can no longer use a
+  pre-compiled regular expression in this case, as it is not serializable.
+  The :attr:`~django.core.validators.RegexValidator.flags` attribute was added
+  to :class:`~django.core.validators.RegexValidator` to simplify this change.
+
 .. _deprecated-features-1.7:
 
 Features deprecated in 1.7

tests/forms_tests/tests/test_validators.py

 from __future__ import unicode_literals
 
+import re
 from unittest import TestCase
 
 from django import forms
@@ -24,11 +25,22 @@ class UserForm(forms.Form):
             )
         ]
     )
+    ignore_case_string = forms.CharField(
+        max_length=50,
+        validators=[
+            validators.RegexValidator(
+                    regex='^[a-z]*$',
+                    message="Letters only.",
+                    flags=re.IGNORECASE,
+                )
+        ]
+
+    )
 
 
 class TestFieldWithValidators(TestCase):
     def test_all_errors_get_reported(self):
-        form = UserForm({'full_name': 'not int nor mail', 'string': '2 is not correct'})
+        form = UserForm({'full_name': 'not int nor mail', 'string': '2 is not correct', 'ignore_case_string': "IgnORE Case strIng"})
         self.assertRaises(ValidationError, form.fields['full_name'].clean, 'not int nor mail')
 
         try:
@@ -38,3 +50,4 @@ class TestFieldWithValidators(TestCase):
 
         self.assertFalse(form.is_valid())
         self.assertEqual(form.errors['string'], ["Letters only."])
+        self.assertEqual(form.errors['string'], ["Letters only."])

tests/validators/tests.py

@@ -198,6 +198,10 @@ TEST_DATA = (
     (RegexValidator(re.compile('x'), inverse_match=True), 'y', None),
     (RegexValidator('x', inverse_match=True), 'x', ValidationError),
     (RegexValidator(re.compile('x'), inverse_match=True), 'x', ValidationError),
+
+    (RegexValidator('x', flags=re.IGNORECASE), 'y', ValidationError),
+    (RegexValidator('a'), 'A', ValidationError),
+    (RegexValidator('a', flags=re.IGNORECASE), 'A', None),
 )
 
 
@@ -250,6 +254,14 @@ class TestSimpleValidators(TestCase):
         self.assertEqual(str(v), str_prefix("{%(_)s'first': [%(_)s'First Problem']}"))
         self.assertEqual(repr(v), str_prefix("ValidationError({%(_)s'first': [%(_)s'First Problem']})"))
 
+    def test_regex_validator_flags(self):
+        try:
+            RegexValidator(re.compile('a'), flags=re.IGNORECASE)
+        except TypeError:
+            pass
+        else:
+            self.fail("TypeError not raised when flags and pre-compiled regex in RegexValidator")
+
 test_counter = 0
 for validator, value, expected in TEST_DATA:
     name, method = create_simple_test_method(validator, expected, value, test_counter)