Fixed #35782 -- Allowed overriding password validation error messages.

django/contrib/auth/password_validation.py

@@ -106,17 +106,16 @@ class MinimumLengthValidator:
 
     def validate(self, password, user=None):
         if len(password) < self.min_length:
-            raise ValidationError(
-                ngettext(
-                    "This password is too short. It must contain at least "
-                    "%(min_length)d character.",
-                    "This password is too short. It must contain at least "
-                    "%(min_length)d characters.",
-                    self.min_length,
-                ),
-                code="password_too_short",
-                params={"min_length": self.min_length},
-            )
+            raise ValidationError(self.get_error_message(), code="password_too_short")
+
+    def get_error_message(self):
+        return ngettext(
+            "This password is too short. It must contain at least %d character."
+            % self.min_length,
+            "This password is too short. It must contain at least %d characters."
+            % self.min_length,
+            self.min_length,
+        )
 
     def get_help_text(self):
         return ngettext(
@@ -203,11 +202,14 @@ class UserAttributeSimilarityValidator:
                     except FieldDoesNotExist:
                         verbose_name = attribute_name
                     raise ValidationError(
-                        _("The password is too similar to the %(verbose_name)s."),
+                        self.get_error_message(),
                         code="password_too_similar",
                         params={"verbose_name": verbose_name},
                     )
 
+    def get_error_message(self):
+        return _("The password is too similar to the %(verbose_name)s.")
+
     def get_help_text(self):
         return _(
             "Your password can’t be too similar to your other personal information."
@@ -242,10 +244,13 @@ class CommonPasswordValidator:
     def validate(self, password, user=None):
         if password.lower().strip() in self.passwords:
             raise ValidationError(
-                _("This password is too common."),
+                self.get_error_message(),
                 code="password_too_common",
             )
 
+    def get_error_message(self):
+        return _("This password is too common.")
+
     def get_help_text(self):
         return _("Your password can’t be a commonly used password.")
 
@@ -258,9 +263,12 @@ class NumericPasswordValidator:
     def validate(self, password, user=None):
         if password.isdigit():
             raise ValidationError(
-                _("This password is entirely numeric."),
+                self.get_error_message(),
                 code="password_entirely_numeric",
             )
 
+    def get_error_message(self):
+        return _("This password is entirely numeric.")
+
     def get_help_text(self):
         return _("Your password can’t be entirely numeric.")

docs/releases/5.2.txt

@@ -82,6 +82,10 @@ Minor features
   improves performance. See :ref:`adding an async interface
   <writing-authentication-backends-async-interface>` for more details.
 
+* The :ref:`password validator classes <included-password-validators>`
+  now have a new method ``get_error_message()``, which can be overridden in
+  subclasses to customize the error messages.
+
 :mod:`django.contrib.contenttypes`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

docs/topics/auth/passwords.txt

@@ -590,6 +590,8 @@ has no settings.
 The help texts and any errors from password validators are always returned in
 the order they are listed in :setting:`AUTH_PASSWORD_VALIDATORS`.
 
+.. _included-password-validators:
+
 Included validators
 -------------------
 
@@ -600,10 +602,18 @@ Django includes four validators:
     Validates that the password is of a minimum length.
     The minimum length can be customized with the ``min_length`` parameter.
 
+    .. method:: get_error_message()
+
+        .. versionadded:: 5.2
+
+        A hook for customizing the ``ValidationError`` error message. Defaults
+        to ``"This password is too short. It must contain at least <min_length>
+        characters."``.
+
     .. method:: get_help_text()
 
         A hook for customizing the validator's help text. Defaults to ``"Your
-        password must contain at least <min_length> characters."``
+        password must contain at least <min_length> characters."``.
 
 .. class:: UserAttributeSimilarityValidator(user_attributes=DEFAULT_USER_ATTRIBUTES, max_similarity=0.7)
 
@@ -622,10 +632,17 @@ Django includes four validators:
     ``user_attributes``, whereas a value of 1.0 rejects only passwords that are
     identical to an attribute's value.
 
+    .. method:: get_error_message()
+
+        .. versionadded:: 5.2
+
+        A hook for customizing the ``ValidationError`` error message. Defaults
+        to ``"The password is too similar to the <user_attribute>."``.
+
     .. method:: get_help_text()
 
         A hook for customizing the validator's help text. Defaults to ``"Your
-        password can’t be too similar to your other personal information."``
+        password can’t be too similar to your other personal information."``.
 
 .. class:: CommonPasswordValidator(password_list_path=DEFAULT_PASSWORD_LIST_PATH)
 
@@ -638,19 +655,33 @@ Django includes four validators:
     common passwords. This file should contain one lowercase password per line
     and may be plain text or gzipped.
 
+    .. method:: get_error_message()
+
+        .. versionadded:: 5.2
+
+        A hook for customizing the ``ValidationError`` error message. Defaults
+        to ``"This password is too common."``.
+
     .. method:: get_help_text()
 
         A hook for customizing the validator's help text. Defaults to ``"Your
-        password can’t be a commonly used password."``
+        password can’t be a commonly used password."``.
 
 .. class:: NumericPasswordValidator()
 
     Validate that the password is not entirely numeric.
 
+    .. method:: get_error_message()
+
+        .. versionadded:: 5.2
+
+        A hook for customizing the ``ValidationError`` error message. Defaults
+        to ``"This password is entirely numeric."``.
+
     .. method:: get_help_text()
 
         A hook for customizing the validator's help text. Defaults to ``"Your
-        password can’t be entirely numeric."``
+        password can’t be entirely numeric."``.
 
 Integrating validation
 ----------------------

tests/auth_tests/test_validators.py

@@ -144,6 +144,20 @@ class MinimumLengthValidatorTest(SimpleTestCase):
             "Your password must contain at least 8 characters.",
         )
 
+    def test_custom_error(self):
+        class CustomMinimumLengthValidator(MinimumLengthValidator):
+            def get_error_message(self):
+                return "Your password must be %d characters long" % self.min_length
+
+        expected_error = "Your password must be %d characters long"
+
+        with self.assertRaisesMessage(ValidationError, expected_error % 8) as cm:
+            CustomMinimumLengthValidator().validate("1234567")
+        self.assertEqual(cm.exception.error_list[0].code, "password_too_short")
+
+        with self.assertRaisesMessage(ValidationError, expected_error % 3) as cm:
+            CustomMinimumLengthValidator(min_length=3).validate("12")
+
 
 class UserAttributeSimilarityValidatorTest(TestCase):
     def test_validate(self):
@@ -213,6 +227,42 @@ class UserAttributeSimilarityValidatorTest(TestCase):
             "Your password can’t be too similar to your other personal information.",
         )
 
+    def test_custom_error(self):
+        class CustomUserAttributeSimilarityValidator(UserAttributeSimilarityValidator):
+            def get_error_message(self):
+                return "The password is too close to the %(verbose_name)s."
+
+        user = User.objects.create_user(
+            username="testclient",
+            password="password",
+            email="testclient@example.com",
+            first_name="Test",
+            last_name="Client",
+        )
+
+        expected_error = "The password is too close to the %s."
+
+        with self.assertRaisesMessage(ValidationError, expected_error % "username"):
+            CustomUserAttributeSimilarityValidator().validate("testclient", user=user)
+
+    def test_custom_error_verbose_name_not_used(self):
+        class CustomUserAttributeSimilarityValidator(UserAttributeSimilarityValidator):
+            def get_error_message(self):
+                return "The password is too close to a user attribute."
+
+        user = User.objects.create_user(
+            username="testclient",
+            password="password",
+            email="testclient@example.com",
+            first_name="Test",
+            last_name="Client",
+        )
+
+        expected_error = "The password is too close to a user attribute."
+
+        with self.assertRaisesMessage(ValidationError, expected_error):
+            CustomUserAttributeSimilarityValidator().validate("testclient", user=user)
+
 
 class CommonPasswordValidatorTest(SimpleTestCase):
     def test_validate(self):
@@ -247,6 +297,16 @@ class CommonPasswordValidatorTest(SimpleTestCase):
             "Your password can’t be a commonly used password.",
         )
 
+    def test_custom_error(self):
+        class CustomCommonPasswordValidator(CommonPasswordValidator):
+            def get_error_message(self):
+                return "This password has been used too much."
+
+        expected_error = "This password has been used too much."
+
+        with self.assertRaisesMessage(ValidationError, expected_error):
+            CustomCommonPasswordValidator().validate("godzilla")
+
 
 class NumericPasswordValidatorTest(SimpleTestCase):
     def test_validate(self):
@@ -264,6 +324,16 @@ class NumericPasswordValidatorTest(SimpleTestCase):
             "Your password can’t be entirely numeric.",
         )
 
+    def test_custom_error(self):
+        class CustomNumericPasswordValidator(NumericPasswordValidator):
+            def get_error_message(self):
+                return "This password is all digits."
+
+        expected_error = "This password is all digits."
+
+        with self.assertRaisesMessage(ValidationError, expected_error):
+            CustomNumericPasswordValidator().validate("42424242")
+
 
 class UsernameValidatorsTests(SimpleTestCase):
     def test_unicode_validator(self):