diff --git a/clients/cloud-setup/nm-cloud-setup-utils.c b/clients/cloud-setup/nm-cloud-setup-utils.c
index 9db3b742c9..39f3b100a1 100644
--- a/clients/cloud-setup/nm-cloud-setup-utils.c
+++ b/clients/cloud-setup/nm-cloud-setup-utils.c
@@ -258,7 +258,6 @@ _poll_task_data_free (gpointer data)
 
 static void
 _poll_return (PollTaskData *poll_task_data,
-              gboolean success,
               GError *error_take)
 {
 	nm_clear_g_source_inst (&poll_task_data->source_next_poll);
@@ -271,7 +270,7 @@ _poll_return (PollTaskData *poll_task_data,
 	if (error_take)
 		g_task_return_error (poll_task_data->task, g_steal_pointer (&error_take));
 	else
-		g_task_return_boolean (poll_task_data->task, success);
+		g_task_return_boolean (poll_task_data->task, TRUE);
 
 	g_object_unref (poll_task_data->task);
 }
@@ -302,7 +301,7 @@ _poll_done_cb (GObject *source,
 
 	if (   error
 	    || is_finished) {
-		_poll_return (poll_task_data, TRUE, g_steal_pointer (&error));
+		_poll_return (poll_task_data, g_steal_pointer (&error));
 		return;
 	}
 
@@ -346,8 +345,8 @@ _poll_timeout_cb (gpointer user_data)
 {
 	PollTaskData *poll_task_data = user_data;
 
-	_poll_return (poll_task_data, FALSE, nm_utils_error_new (NM_UTILS_ERROR_UNKNOWN,
-	                                                         "timeout expired"));
+	_poll_return (poll_task_data, nm_utils_error_new (NM_UTILS_ERROR_UNKNOWN,
+	                                                  "timeout expired"));
 	return G_SOURCE_CONTINUE;
 }
 
@@ -360,13 +359,13 @@ _poll_cancelled_cb (GObject *object, gpointer user_data)
 	nm_clear_g_signal_handler (g_task_get_cancellable (poll_task_data->task),
 	                           &poll_task_data->cancellable_id);
 	nm_utils_error_set_cancelled (&error, FALSE, NULL);
-	_poll_return (poll_task_data, FALSE, error);
+	_poll_return (poll_task_data, error);
 }
 
 /**
  * nmcs_utils_poll:
  * @poll_timeout_ms: if >= 0, then this is the overall timeout for how long we poll.
- *   When this timeout expires, the request completes with failure (but no error set).
+ *   When this timeout expires, the request completes with failure (and error set).
  * @ratelimit_timeout_ms: if > 0, we ratelimit the starts from one prope_start_fcn
  *   call to the next.
  * @sleep_timeout_ms: if > 0, then we wait after a probe finished this timeout
@@ -459,7 +458,8 @@ nmcs_utils_poll (int poll_timeout_ms,
  *   %FALSE will be returned.
  *   If the probe returned a failure, this returns %FALSE and the error
  *   provided by @probe_finish_fcn.
- *   If the request times out, this returns %FALSE without error set.
+ *   If the request times out, this returns %FALSE with error set.
+ *   Error is always set if (and only if) the function returns %FALSE.
  */
 gboolean
 nmcs_utils_poll_finish (GAsyncResult *result,
diff --git a/clients/cloud-setup/nm-http-client.c b/clients/cloud-setup/nm-http-client.c
index 24d42e3d5f..7f042c8af6 100644
--- a/clients/cloud-setup/nm-http-client.c
+++ b/clients/cloud-setup/nm-http-client.c
@@ -505,10 +505,12 @@ _poll_get_done_cb (GObject *source,
 
 	success = nmcs_utils_poll_finish (result, NULL, &error);
 
+	nm_assert ((!!success) == (!error));
+
 	if (error)
 		g_task_return_error (poll_get_data->task, g_steal_pointer (&error));
 	else
-		g_task_return_boolean (poll_get_data->task, success);
+		g_task_return_boolean (poll_get_data->task, TRUE);
 
 	g_object_unref (poll_get_data->task);
 }
@@ -587,10 +589,11 @@ nm_http_client_poll_get_finish (NMHttpClient *self,
 	task = G_TASK (result);
 
 	success = g_task_propagate_boolean (task, &local_error);
-	if (   local_error
-	    || !success) {
-		if (local_error)
-			g_propagate_error (error, g_steal_pointer (&local_error));
+
+	nm_assert ((!!success) == (!local_error));
+
+	if (local_error) {
+		g_propagate_error (error, g_steal_pointer (&local_error));
 		NM_SET_OUT (out_response_code, -1);
 		NM_SET_OUT (out_response_data, NULL);
 		return FALSE;
@@ -600,7 +603,6 @@ nm_http_client_poll_get_finish (NMHttpClient *self,
 
 	NM_SET_OUT (out_response_code, poll_get_data->response_code);
 	NM_SET_OUT (out_response_data, g_steal_pointer (&poll_get_data->response_data));
-
 	return TRUE;
 }