misc: always add service variables to login condition context (#60125)

src/authentic2/views.py

@@ -350,6 +350,10 @@ def login(request, template_name='authentic2/login.html', redirect_field_name=RE
                 show_ctx['service_ou_slug'] = service.ou and service.ou.slug
                 show_ctx['service_slug'] = service.slug
                 show_ctx['service'] = service
+            else:
+                show_ctx['service_ou_slug'] = ''
+                show_ctx['service_slug'] = ''
+                show_ctx['service'] = None
             # check if the authenticator has multiple instances
             if hasattr(authenticator, 'instances'):
                 for instance_id, instance in authenticator.instances(**parameters):

tests/test_login.py

@@ -87,8 +87,12 @@ def test_show_condition(db, app, settings, caplog):
 
 def test_show_condition_service(db, app, settings):
     settings.AUTH_FRONTENDS_KWARGS = {'password': {'show_condition': 'service_slug == \'portal\''}}
+    response = app.get('/login/', params={})
+    assert 'name="login-password-submit"' not in response
+
+    # service doesn't exist
     response = app.get('/login/', params={'service': 'portal'})
-    assert 'name="login-password-submit"' in response
+    assert 'name="login-password-submit"' not in response
 
     # Create a service
     models.Service.objects.create(name='Service', slug='portal')