lib: fix removal of yang non-presence containers

Non-presence containers don't have "destroy" callbacks. So, once
a np-container is deleted, we need to call the "destroy" callbacks
of its child nodes instead.

This commit doesn't fix any real problem as of now since all
np-containers from the FRR YANG modules contain or one more mandatory
child nodes, so they can't be deleted (libyang will add missing
np-containers when validating data). Nevertheless, upcoming YANG
modules should benefit from this change.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 21 insertions, 2 deletions

diff --git a/lib/northbound.c b/lib/northbound.c
index fd71579ff..edf7e0eca 100644
--- a/lib/northbound.c
+++ b/lib/northbound.c
@@ -384,6 +384,26 @@ static void nb_config_diff_created(const struct lyd_node *dnode,
 	}
 }
 
+static void nb_config_diff_deleted(const struct lyd_node *dnode,
+				   struct nb_config_cbs *changes)
+{
+	if (nb_operation_is_valid(NB_OP_DESTROY, dnode->schema))
+		nb_config_diff_add_change(changes, NB_OP_DESTROY, dnode);
+	else if (CHECK_FLAG(dnode->schema->nodetype, LYS_CONTAINER)) {
+		struct lyd_node *child;
+
+		/*
+		 * Non-presence containers need special handling since they
+		 * don't have "destroy" callbacks. In this case, what we need to
+		 * do is to call the "destroy" callbacks of their child nodes
+		 * when applicable (i.e. optional nodes).
+		 */
+		LY_TREE_FOR (dnode->child, child) {
+			nb_config_diff_deleted(child, changes);
+		}
+	}
+}
+
 /* Calculate the delta between two different configurations. */
 static void nb_config_diff(const struct nb_config *config1,
 			   const struct nb_config *config2,
@@ -408,8 +428,7 @@ static void nb_config_diff(const struct nb_config *config1,
 			break;
 		case LYD_DIFF_DELETED:
 			dnode = diff->first[i];
-			nb_config_diff_add_change(changes, NB_OP_DESTROY,
-						  dnode);
+			nb_config_diff_deleted(dnode, changes);
 			break;
 		case LYD_DIFF_CHANGED:
 			dnode = diff->second[i];