New immutable object type that is properly frozen. Part of #155

djadmin2/tests/test_types.py

@@ -0,0 +1,36 @@
+from django.test import TestCase
+
+from ..types import immutable_admin_factory
+
+
+class ModelAdmin(object):
+    model_admin_attributes = ['a', 'b', 'c']
+    a = 1  # covered
+    b = 2  # covered
+    c = 3  # covered
+    d = 4  # not covered
+
+
+class ImmutableAdminFactoryTests(TestCase):
+
+    def setUp(self):
+        self.immutable_admin = immutable_admin_factory(ModelAdmin)
+
+    def test_immutability(self):
+        with self.assertRaises(AttributeError):
+            # can't set attribute
+            self.immutable_admin.a = 10
+        with self.assertRaises(AttributeError):
+            # 'ImmutableAdmin' object has no attribute 'e'
+            self.immutable_admin.e = 5
+        with self.assertRaises(AttributeError):
+            # can't delete attribute
+            del self.immutable_admin.a
+
+    def test_attributes(self):
+        self.assertEquals(self.immutable_admin.a, 1)
+        self.assertEquals(self.immutable_admin.b, 2)
+        self.assertEquals(self.immutable_admin.c, 3)
+        with self.assertRaises(AttributeError):
+            # 'ImmutableAdmin' object has no attribute 'd'
+            self.immutable_admin.d

djadmin2/types.py

@@ -0,0 +1,14 @@
+from collections import namedtuple
+
+
+def immutable_admin_factory(model_admin):
+    """ Provide an ImmutableAdmin to make it harder for developers to dig themselves into holes.
+        See https://github.com/twoscoops/django-admin2/issues/99
+        Frozen class implementation as namedtuple suggested by Audrey Roy
+
+        Note: This won't stop developers from saving mutable objects to the result, but hopefully
+                developers attempting that 'workaround/hack' will read our documentation.
+    """
+    ImmutableAdmin = namedtuple("ImmutableAdmin", model_admin.model_admin_attributes, verbose=False)
+    return ImmutableAdmin(*[getattr(model_admin, x) for x in model_admin.model_admin_attributes])
+