From 3569ba0333ef7f90640aa2042339451705d20114 Mon Sep 17 00:00:00 2001
From: Claude Paroz <claude@2xlibre.net>
Date: Fri, 5 Aug 2016 11:38:39 +0200
Subject: [PATCH] Fixed #27015 -- Prevented HTML-invalid minlength/maxlength on
 hidden inputs

---
 django/forms/fields.py                          | 4 ++--
 tests/forms_tests/field_tests/test_charfield.py | 7 +++++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/django/forms/fields.py b/django/forms/fields.py
index ff71328f52..45b425efd6 100644
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@@ -236,10 +236,10 @@ class CharField(Field):
 
     def widget_attrs(self, widget):
         attrs = super(CharField, self).widget_attrs(widget)
-        if self.max_length is not None:
+        if self.max_length is not None and not widget.is_hidden:
             # The HTML attribute is maxlength, not max_length.
             attrs['maxlength'] = str(self.max_length)
-        if self.min_length is not None:
+        if self.min_length is not None and not widget.is_hidden:
             # The HTML attribute is minlength, not min_length.
             attrs['minlength'] = str(self.min_length)
         return attrs
diff --git a/tests/forms_tests/field_tests/test_charfield.py b/tests/forms_tests/field_tests/test_charfield.py
index 906b91bc75..a08a1a4e42 100644
--- a/tests/forms_tests/field_tests/test_charfield.py
+++ b/tests/forms_tests/field_tests/test_charfield.py
@@ -1,7 +1,7 @@
 from __future__ import unicode_literals
 
 from django.forms import (
-    CharField, PasswordInput, Textarea, TextInput, ValidationError,
+    CharField, HiddenInput, PasswordInput, Textarea, TextInput, ValidationError,
 )
 from django.test import SimpleTestCase
 
@@ -79,7 +79,9 @@ class CharFieldTest(FormFieldAssertionsMixin, SimpleTestCase):
 
     def test_charfield_widget_attrs(self):
         """
-        CharField.widget_attrs() always returns a dictionary (#15912).
+        CharField.widget_attrs() always returns a dictionary and includes
+        minlength/maxlength if min_length/max_length are defined on the field
+        and the widget is not hidden.
         """
         # Return an empty dictionary if max_length and min_length are both None.
         f = CharField()
@@ -104,6 +106,7 @@ class CharFieldTest(FormFieldAssertionsMixin, SimpleTestCase):
         self.assertEqual(f.widget_attrs(TextInput()), {'maxlength': '10', 'minlength': '5'})
         self.assertEqual(f.widget_attrs(PasswordInput()), {'maxlength': '10', 'minlength': '5'})
         self.assertEqual(f.widget_attrs(Textarea()), {'maxlength': '10', 'minlength': '5'})
+        self.assertEqual(f.widget_attrs(HiddenInput()), {})
 
     def test_charfield_strip(self):
         """