Fix parsing for notification after leaf

This commit fixes parsing of notification messages for the case where the
notification follows a leaf. Prior to this change, if the notification
followed a leaf, the notification would be missed. In the `LYS_LEAF` case,
`elem` would be advanced to `elem->next` (the notification), but the `for`
loop condition to detect the notification would not be re-evaluated due to the
`goto next_node` jump. By the time the loop condition was re-evaluated, `elem`
would have been advanced to the notification's child.

We've written integration tests that demonstrate the problem. This commit,
together with a forthcoming commit to sysrepo, will allow those failing test
cases to pass. (See [CI results], lines 7282-7284, or [test source code].)
These test cases cover several different variations of notifications tied to
data nodes.

[CI results]: https://travis-ci.org/ADTRAN/netopeer2-integration-tests/builds/414144146#L7282
[test source code]: https://github.com/ADTRAN/netopeer2-integration-tests/blob/master/tests/test_notif.py#L229

Author: alangefe

src/messages_server.c

@@ -16,6 +16,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
+#include <stdbool.h>
 
 #include <libyang/libyang.h>
 
@@ -828,6 +829,7 @@ nc_server_notif_new(struct lyd_node* event, char *eventtime, NC_PARAMTYPE paramt
 {
     struct nc_server_notif *ntf;
     struct lyd_node *elem;
+    bool found_notif = false;
 
     if (!event) {
         ERRARG("event");
@@ -838,7 +840,7 @@ nc_server_notif_new(struct lyd_node* event, char *eventtime, NC_PARAMTYPE paramt
     }
 
     /* check that there is a notification */
-    for (elem = event; elem && (elem->schema->nodetype != LYS_NOTIF); elem = elem->child) {
+    for (elem = event; elem && !found_notif; elem = elem->child) {
 next_node:
         switch (elem->schema->nodetype) {
         case LYS_LEAF:
@@ -852,16 +854,18 @@ nc_server_notif_new(struct lyd_node* event, char *eventtime, NC_PARAMTYPE paramt
             goto next_node;
         case LYS_CONTAINER:
         case LYS_LIST:
-        case LYS_NOTIF:
             /* ok */
             break;
+        case LYS_NOTIF:
+            found_notif = true;
+            break;
         default:
             /* error */
             ERRARG("event");
             return NULL;
         }
     }
-    if (!elem) {
+    if (!found_notif) {
         ERRARG("event");
         return NULL;
     }