[3.0.x] Fixed #31154 -- Added support for using enumeration types in …

…templates.

Enumeration helpers are callables, so the template system tried to call
them with no arguments.

Thanks Rupert Baker for helping discover this.

Backport of 5166097 from master

django/db/models/enums.py

@@ -31,6 +31,7 @@ def __new__(metacls, classname, bases, classdict):
         # that is passed in as "self" as the value to use when looking up the
         # label in the choices.
         cls.label = property(lambda self: cls._value2label_map_.get(self.value))
+        cls.do_not_call_in_templates = True
         return enum.unique(cls)
 
     def __contains__(cls, member):

docs/releases/3.0.3.txt

@@ -20,3 +20,6 @@ Bugfixes
 * Relaxed the system check added in Django 3.0 to reallow use of a sublanguage
   in the :setting:`LANGUAGE_CODE` setting, when a base language is available in
   Django but the sublanguage is not (:ticket:`31141`).
+
+* Added support for using enumeration types ``TextChoices``,
+  ``IntegerChoices``, and ``Choices`` in templates (:ticket:`31154`).

tests/model_enums/tests.py

@@ -4,6 +4,7 @@
 import uuid
 
 from django.db import models
+from django.template import Context, Template
 from django.test import SimpleTestCase
 from django.utils.functional import Promise
 from django.utils.translation import gettext_lazy as _
@@ -149,6 +150,11 @@ def test_str(self):
                 with self.subTest(member=member):
                     self.assertEqual(str(test[member.name]), str(member.value))
 
+    def test_templates(self):
+        template = Template('{{ Suit.DIAMOND.label }}|{{ Suit.DIAMOND.value }}')
+        output = template.render(Context({'Suit': Suit}))
+        self.assertEqual(output, 'Diamond|1')
+
 
 class Separator(bytes, models.Choices):
     FS = b'\x1c', 'File Separator'