Fixed #31144 -- Relaxed system check for max_length of CharFields on MySQL/MariaDB by turning into a warning.

tests/invalid_models_tests/test_ordinary_fields.py

@@ -8,6 +8,7 @@ from django.test.utils import isolate_apps, override_settings
 from django.utils.functional import lazy
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
+from django.utils.version import get_docs_version
 
 
 @isolate_apps('invalid_models_tests')
@@ -372,11 +373,15 @@ class CharFieldTests(SimpleTestCase):
         field = Model._meta.get_field('field')
         validator = DatabaseValidation(connection=connection)
         self.assertEqual(validator.check_field(field), [
-            Error(
-                '%s does not allow unique CharFields to have a max_length > '
+            DjangoWarning(
+                '%s may not allow unique CharFields to have a max_length > '
                 '255.' % connection.display_name,
+                hint=(
+                    'See: https://docs.djangoproject.com/en/%s/ref/databases/'
+                    '#mysql-character-fields' % get_docs_version()
+                ),
                 obj=field,
-                id='mysql.E001',
+                id='mysql.W003',
             )
         ])