lib: fix iteration over schema nodes of a single YANG module

The only safe way to iterate over all schema nodes of a given YANG
module is by iterating over all schema nodes of all YANG modules
and filter out the nodes that belong to other modules.

The original yang_snodes_iterate_module() code did the following:
1 - Iterate over all top-level schema nodes of the given module;
2 - Iterate over all augmentations of the given module.

While that iteration strategy is more efficient, it does't handle
well more complex YANG hierarchies containing nested augmentations
or self-augmenting modules. Any iteration that isn't done on the
resolved YANG data hierarchy is fragile and prone to errors.

Fixes regression introduced by commit 8a923b48513316b where the
gen_northbound_callbacks tool was generating duplicate callbacks
for certain modules.

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

1 files changed, 14 insertions, 13 deletions

diff --git a/lib/yang.c b/lib/yang.c
index 5bf7758e1..46012acf5 100644
--- a/lib/yang.c
+++ b/lib/yang.c
@@ -230,22 +230,23 @@ next:
 int yang_snodes_iterate_module(const struct lys_module *module,
 			       yang_iterate_cb cb, uint16_t flags, void *arg)
 {
-	struct lys_node *snode;
+	const struct lys_module *module_iter;
+	uint32_t idx = 0;
 	int ret = YANG_ITER_CONTINUE;
 
-	LY_TREE_FOR (module->data, snode) {
-		ret = yang_snodes_iterate_subtree(snode, module, cb, flags,
-						  arg);
-		if (ret == YANG_ITER_STOP)
-			return ret;
-	}
+	idx = ly_ctx_internal_modules_count(ly_native_ctx);
+	while ((module_iter = ly_ctx_get_module_iter(ly_native_ctx, &idx))) {
+		struct lys_node *snode;
 
-	for (uint8_t i = 0; i < module->augment_size; i++) {
-		ret = yang_snodes_iterate_subtree(
-			(const struct lys_node *)&module->augment[i], module,
-			cb, flags, arg);
-		if (ret == YANG_ITER_STOP)
-			return ret;
+		if (!module_iter->implemented)
+			continue;
+
+		LY_TREE_FOR (module_iter->data, snode) {
+			ret = yang_snodes_iterate_subtree(snode, module, cb,
+							  flags, arg);
+			if (ret == YANG_ITER_STOP)
+				return ret;
+		}
 	}
 
 	return ret;