yanglint BUGFIX validating data even no input data file specified

In non-interactive mode, when no output format specified (only validation
required) and no data input file given (schema validation required),
the data tree was anyway validated which could fail if the provided schemas
to validate contain mandatory status data

Author: rkrejci

tools/lint/main_ni.c

@@ -179,7 +179,7 @@ main_ni(int argc, char* argv[])
         struct dataitem *next;
     } *data = NULL, *data_item;
     struct ly_set *mods = NULL;
-    struct lyd_node *root = NULL, *node, *next, *subroot;
+    struct lyd_node *root = NULL, *node = NULL, *next, *subroot;
     struct lyxml_elem *xml = NULL;
 
     opterr = 0;
@@ -434,7 +434,7 @@ main_ni(int argc, char* argv[])
         for (u = 0; u < mods->number; u++) {
             lys_print_file(out, (struct lys_module *)mods->set.g[u], outformat_s, NULL);
         }
-    } else {
+    } else if (data) {
         ly_errno = 0;
         if (!options_parser) {
             /* LYD_OPT_DATA - status data fro ietf-yang-library are needed */
@@ -501,7 +501,7 @@ main_ni(int argc, char* argv[])
             }
         }
         /* validate the data */
-        if (outformat_d || root) {
+        if (data) {
             /* do not trust the input, invalidate all the data first */
             LY_TREE_FOR(root, subroot) {
                 LY_TREE_DFS_BEGIN(subroot, next, node) {