Fixed #20846 -- Increased User.username max_length to 254 characters.

Thanks Collin Anderson and Nick Sandford for work on the patch.

2 files changed, 34 insertions, 2 deletions

diff --git a/django/contrib/auth/migrations/0008_alter_user_username_max_length.py b/django/contrib/auth/migrations/0008_alter_user_username_max_length.py
new file mode 100644
index 0000000000..56705fa58f
--- /dev/null
+++ b/django/contrib/auth/migrations/0008_alter_user_username_max_length.py
@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('auth', '0007_alter_validators_add_error_messages'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='user',
+            name='username',
+            field=models.CharField(
+                error_messages={'unique': 'A user with that username already exists.'},
+                help_text='Required. 254 characters or fewer. Letters, digits and @/./+/-/_ only.',
+                max_length=254,
+                unique=True,
+                validators=[
+                    django.core.validators.RegexValidator(
+                        '^[\\w.@+-]+$', 'Enter a valid username. '
+                        'This value may contain only letters, numbers and @/./+/-/_ characters.'
+                    ),
+                ],
+                verbose_name='username',
+            ),
+        ),
+    ]
diff --git a/django/contrib/auth/models.py b/django/contrib/auth/models.py
index 070d7d4435..dfa76977d7 100644
--- a/django/contrib/auth/models.py
+++ b/django/contrib/auth/models.py
@@ -303,9 +303,9 @@ class AbstractUser(AbstractBaseUser, PermissionsMixin):
     """
     username = models.CharField(
         _('username'),
-        max_length=30,
+        max_length=254,
         unique=True,
-        help_text=_('Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.'),
+        help_text=_('Required. 254 characters or fewer. Letters, digits and @/./+/-/_ only.'),
         validators=[
             validators.RegexValidator(
                 r'^[\w.@+-]+$',