auth_saml: raise error when no saml attribute value received (#47706)

src/authentic2_auth_saml/adapters.py

@@ -158,8 +158,10 @@ class AuthenticAdapter(DefaultAdapter):
 
     def set_user_attribute(self, user, attribute, value):
         if isinstance(value, list):
+            if len(value) == 0:
+                raise MappingError('no value for %s' % attribute, details={'attribute': attribute})
             if len(value) > 1:
-                raise MappingError('too much values')
+                raise MappingError('too many values for %s' % attribute, details={'attribute': attribute})
             value = value[0]
         if attribute in ('first_name', 'last_name', 'email', 'username'):
             if getattr(user, attribute) != value:

tests/test_auth_saml.py

@@ -23,6 +23,8 @@ import lasso
 
 from django.contrib.auth import get_user_model
 from authentic2.models import Attribute
+from authentic2_auth_saml.adapters import MappingError
+
 
 def test_providers_on_login_page(db, app, settings):
     settings.A2_AUTH_SAML_ENABLE = True
@@ -134,6 +136,16 @@ def test_provision_attributes(db, caplog, simple_role):
     del saml_attributes['mail']
     assert adapter.lookup_user(idp, saml_attributes) is None
 
+    # simulate no attribute value
+    saml_attributes['first_name'] = []
+    mapping = {
+        'attribute': 'first_name',
+        'saml_attribute': 'first_name',
+    }
+    with pytest.raises(MappingError, match='no value for first_name'):
+        adapter.action_set_attribute(user, idp, saml_attributes, mapping)
+
+
 
 def test_login_with_conditionnal_authenticators(db, app, settings, caplog):