Log invalid model field in attribute mapping

If a field is declared in the attributes mapping but does not exist on
the User model nor the Profile, log it instead of ignoring silently.

Author: francoisfreitag

CHANGES

@@ -3,6 +3,7 @@ Changes
 
 UNRELEASED
 ----------
+- Log when attribute_mapping maps to nonexistent User fields.
 - Dropped compatibility for Python < 2.7 and Django < 1.8.
 
 0.16.10 (2017-10-02)

djangosaml2/backends.py

@@ -226,6 +226,9 @@ def update_user(self, user, attributes, attribute_mapping,
                         modified = self._set_attribute(user, attr, attr_value_list[0])
 
                     user_modified = user_modified or modified
+                else:
+                    logger.debug(
+                        'Could not find attribute "%s" on user "%s"', attr, user)
 
         logger.debug('Sending the pre_save signal')
         signal_modified = any(

tests/testprofiles/tests.py

@@ -108,6 +108,26 @@ def test_update_user_empty_attribute(self):
         # empty attribute list: no update
         self.assertEqual(user.last_name, 'Smith')
 
+    def test_invalid_model_attribute_log(self):
+        backend = Saml2Backend()
+
+        attribute_mapping = {
+            'uid': ['username'],
+            'cn': ['nonexistent'],
+        }
+        attributes = {
+            'uid': ['john'],
+            'cn': ['John'],
+        }
+
+        with self.assertLogs('djangosaml2', level='DEBUG') as logs:
+            backend.get_saml2_user(True, 'john', attributes, attribute_mapping)
+
+        self.assertIn(
+            'DEBUG:djangosaml2:Could not find attribute "nonexistent" on user "john"',
+            logs.output,
+        )
+
     def test_django_user_main_attribute(self):
         backend = Saml2Backend()