data tree CHANGE lyd_new_leaf_val removed

lyd_new_leaf_str renamed to lyd_new_leaf,
union resolution fixed.
diff --git a/tools/lint/commands.c b/tools/lint/commands.c
index 41e39c5..4675b0c 100644
--- a/tools/lint/commands.c
+++ b/tools/lint/commands.c
@@ -657,6 +657,9 @@
     int has_modules = 0;
 
     ylib = ly_ctx_info(ctx);
+    if (!ylib) {
+        return 1;
+    }
 
     LY_TREE_FOR(ylib->child, node) {
         if (!strcmp(node->schema->name, "module-set-id")) {