libyang BUGFIX properly handle union values

Fixes #2342

Author: michalvasko

src/schema_compile.c

@@ -937,6 +937,7 @@ lys_compile_unres_dflt(struct lysc_ctx *ctx, struct lysc_node *node, struct lysc
 {
     LY_ERR ret;
     uint32_t options;
+    struct lyd_value *val;
     struct ly_err_item *err = NULL;
 
     options = (ctx->ctx->flags & LY_CTX_REF_IMPLEMENTED) ? LYPLG_TYPE_STORE_IMPLEMENT : 0;
@@ -963,11 +964,16 @@ lys_compile_unres_dflt(struct lysc_ctx *ctx, struct lysc_node *node, struct lysc
     }
 
     LY_ATOMIC_INC_BARRIER(((struct lysc_type *)storage->realtype)->refcount);
-    if (storage->realtype->basetype == LY_TYPE_INST) {
+    if (storage->realtype->basetype == LY_TYPE_UNION) {
+        val = &storage->subvalue->value;
+    } else {
+        val = storage;
+    }
+    if (val->realtype->basetype == LY_TYPE_INST) {
         /* ly_path includes references to other nodes, in case they are in foreign modules, the context would
          * need to be freed in specific order to avoid accessing freed memory, so just avoid storing it */
-        ly_path_free(storage->target);
-        storage->target = NULL;
+        ly_path_free(val->target);
+        val->target = NULL;
     }
     return LY_SUCCESS;
 }

src/xpath.c

@@ -3690,6 +3690,7 @@ xpath_bit_is_set(struct lyxp_set **args, uint32_t UNUSED(arg_count), struct lyxp
     struct lyd_node_term *leaf;
     struct lysc_node_leaf *sleaf;
     struct lyd_value_bits *bits;
+    struct lyd_value *val;
     LY_ERR rc = LY_SUCCESS;
     LY_ARRAY_COUNT_TYPE u;
 
@@ -3725,10 +3726,14 @@ xpath_bit_is_set(struct lyxp_set **args, uint32_t UNUSED(arg_count), struct lyxp
     LY_CHECK_RET(rc);
 
     set_fill_boolean(set, 0);
-    if (args[0]->used) {
+    if (args[0]->used && (args[0]->val.nodes[0].node->schema->nodetype & LYD_NODE_TERM)) {
         leaf = (struct lyd_node_term *)args[0]->val.nodes[0].node;
-        if ((leaf->schema->nodetype & (LYS_LEAF | LYS_LEAFLIST)) && (leaf->value.realtype->basetype == LY_TYPE_BITS)) {
-            LYD_VALUE_GET(&leaf->value, bits);
+        val = &leaf->value;
+        if (val->realtype->basetype == LY_TYPE_UNION) {
+            val = &val->subvalue->value;
+        }
+        if (val->realtype->basetype == LY_TYPE_BITS) {
+            LYD_VALUE_GET(val, bits);
             LY_ARRAY_FOR(bits->items, u) {
                 if (!strcmp(bits->items[u]->name, args[1]->val.str)) {
                     set_fill_boolean(set, 1);
@@ -4200,17 +4205,21 @@ xpath_derived_(struct lyxp_set **args, struct lyxp_set *set, uint32_t options, l
             leaf = (struct lyd_node_term *)args[0]->val.nodes[i].node;
             sleaf = (struct lysc_node_leaf *)leaf->schema;
             val = &leaf->value;
-            if (!sleaf || !(sleaf->nodetype & LYD_NODE_TERM) || (leaf->value.realtype->basetype != LY_TYPE_IDENT)) {
+            if (!sleaf || !(sleaf->nodetype & LYD_NODE_TERM)) {
                 /* uninteresting */
                 continue;
             }
         } else {
             meta = args[0]->val.meta[i].meta;
             val = &meta->value;
-            if (val->realtype->basetype != LY_TYPE_IDENT) {
-                /* uninteresting */
-                continue;
-            }
+        }
+
+        if (val->realtype->basetype == LY_TYPE_UNION) {
+            val = &val->subvalue->value;
+        }
+        if (val->realtype->basetype != LY_TYPE_IDENT) {
+            /* uninteresting */
+            continue;
         }
 
         /* check the identity itself */