tree data UPDATE proper dup support for ext data

Fixes #2385

Author: michalvasko

src/diff.c

@@ -412,12 +412,7 @@ lyd_diff_add(const struct lyd_node *node, enum lyd_diff_op op, const char *orig_
         }
 
         /* duplicate the subtree (and connect to the diff if possible) */
-        if (diff_parent) {
-            LY_CHECK_RET(lyd_dup_single_to_ctx(node, LYD_CTX(diff_parent), (struct lyd_node_inner *)diff_parent,
-                    diff_opts, &dup));
-        } else {
-            LY_CHECK_RET(lyd_dup_single(node, NULL, diff_opts, &dup));
-        }
+        LY_CHECK_RET(lyd_dup_single(node, (struct lyd_node_inner *)diff_parent, diff_opts, &dup));
 
         /* find the first duplicated parent */
         if (!diff_parent) {
@@ -2768,13 +2763,8 @@ lyd_diff_merge_r(const struct lyd_node *src_diff, struct lyd_node *diff_parent,
     } else {
 add_diff:
         /* add new diff node with all descendants */
-        if ((src_diff->flags & LYD_EXT) && diff_parent) {
-            LY_CHECK_RET(lyd_dup_single_to_ctx(src_diff, LYD_CTX(diff_parent), (struct lyd_node_inner *)diff_parent,
-                    LYD_DUP_RECURSIVE | LYD_DUP_WITH_FLAGS | LYD_DUP_NO_LYDS, &diff_node));
-        } else {
-            LY_CHECK_RET(lyd_dup_single(src_diff, (struct lyd_node_inner *)diff_parent,
-                    LYD_DUP_RECURSIVE | LYD_DUP_WITH_FLAGS | LYD_DUP_NO_LYDS, &diff_node));
-        }
+        LY_CHECK_RET(lyd_dup_single(src_diff, (struct lyd_node_inner *)diff_parent,
+                LYD_DUP_RECURSIVE | LYD_DUP_WITH_FLAGS | LYD_DUP_NO_LYDS, &diff_node));
 
         /* insert node into diff if not already */
         if (!diff_parent) {