From 10f211e9c3ffc3a01344f30f502c7f80280fc224 Mon Sep 17 00:00:00 2001
From: Stefan Gula <steweg@gmail.com>
Date: Sun, 28 Sep 2025 23:14:17 +0200
Subject: [PATCH] parsing BUGFIX invalid backward parent pointer

This patch fixes the issue if extensions are used within subsequent
refine or typedef statements
---
 src/parser_yang.c                 | 16 ++++++++
 tests/utests/basic/test_plugins.c | 61 +++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+)

diff --git a/src/parser_yang.c b/src/parser_yang.c
index 928533022..7238e0762 100644
--- a/src/parser_yang.c
+++ b/src/parser_yang.c
@@ -2722,9 +2722,17 @@ parse_refine(struct lysp_yang_ctx *ctx, struct lysp_refine **refines)
     size_t word_len;
     enum ly_stmt kw;
     struct lysp_refine *rf;
+    LY_ARRAY_COUNT_TYPE u, v;
 
     LY_ARRAY_NEW_RET(PARSER_CTX(ctx), *refines, rf, LY_EMEM);
 
+    /* revalidate the backward parent pointers from extensions. The realloc within LY_ARRAY_NEW_RET is making previous entries invalid */
+    LY_ARRAY_FOR(*refines, u) {
+        LY_ARRAY_FOR((*refines)[u].exts, v) {
+            (*refines)[u].exts[v].parent = &(*refines)[u];
+        }
+    }
+
     /* get value */
     LY_CHECK_RET(get_argument(ctx, Y_STR_ARG, NULL, &word, &buf, &word_len));
     CHECK_NONEMPTY(ctx, word_len, "refine");
@@ -2792,9 +2800,17 @@ parse_typedef(struct lysp_yang_ctx *ctx, struct lysp_node *parent, struct lysp_t
     size_t word_len;
     enum ly_stmt kw;
     struct lysp_tpdf *tpdf;
+    LY_ARRAY_COUNT_TYPE u, v;
 
     LY_ARRAY_NEW_RET(PARSER_CTX(ctx), *typedefs, tpdf, LY_EMEM);
 
+    /* revalidate the backward parent pointers from extensions. The realloc within LY_ARRAY_NEW_RET is making previous entries invalid */
+    LY_ARRAY_FOR(*typedefs, u) {
+        LY_ARRAY_FOR((*typedefs)[u].exts, v) {
+            (*typedefs)[u].exts[v].parent = &(*typedefs)[u];
+        }
+    }
+
     /* get value */
     LY_CHECK_RET(get_argument(ctx, Y_IDENTIF_ARG, NULL, &word, &buf, &word_len));
     INSERT_WORD_GOTO(ctx, buf, tpdf->name, word, word_len, ret, cleanup);
diff --git a/tests/utests/basic/test_plugins.c b/tests/utests/basic/test_plugins.c
index d8422d795..d36fa7d16 100644
--- a/tests/utests/basic/test_plugins.c
+++ b/tests/utests/basic/test_plugins.c
@@ -26,10 +26,31 @@ const char *simple = "module libyang-plugins-simple {"
         "  prefix s;"
         "  typedef note { type string; }"
         "  extension hint { argument value; }"
+        "  extension rt;"
         "  leaf test {"
         "    type s:note {length 255;}"
         "    s:hint \"some hint here\";"
         "  }"
+        "  grouping grp1 {"
+        "    list l1 {key v; leaf v {type string;} leaf k {type string;}}"
+        "    list l2 {key v; leaf v {type string;} leaf k {type string;}}"
+        "    typedef t1 {"
+        "      type string;"
+        "      s:rt;"
+        "    }"
+        "    typedef t2 {"
+        "      type string;"
+        "      s:rt;"
+        "    }"
+        "  }"
+        "  uses grp1 {"
+        "    refine l1 {"
+        "      s:rt;"
+        "    }"
+        "    refine l2 {"
+        "      s:rt;"
+        "    }"
+        "  }"
         "}";
 
 static void
@@ -106,6 +127,29 @@ parse_clb(struct lysp_ctx *UNUSED(pctx), struct lysp_ext_instance *ext)
     return LY_SUCCESS;
 }
 
+static LY_ERR
+parse_clb2(struct lysp_ctx *UNUSED(pctx), struct lysp_ext_instance *ext)
+{
+    struct lysp_refine *refine;
+    struct lysp_tpdf *tpdf;
+    LY_ARRAY_COUNT_TYPE count = 0;
+
+    if (ext->parent_stmt == LY_STMT_REFINE) {
+        refine = (struct lysp_refine *)ext->parent;
+        count = LY_ARRAY_COUNT(refine->exts);
+    } else if (ext->parent_stmt == LY_STMT_TYPEDEF) {
+        tpdf = (struct lysp_tpdf *)ext->parent;
+        count = LY_ARRAY_COUNT(tpdf->exts);
+    } else {
+        return LY_SUCCESS;
+    }
+
+    if (count != 1) {
+        return LY_EINVAL;
+    }
+    return LY_SUCCESS;
+}
+
 struct lyplg_ext_record memory_recs[] = {
     {
         .module = "libyang-plugins-simple",
@@ -124,6 +168,23 @@ struct lyplg_ext_record memory_recs[] = {
         .plugin.pfree = NULL,
         .plugin.cfree = NULL
     },
+    {
+        .module = "libyang-plugins-simple",
+        .revision = NULL,
+        .name = "rt",
+
+        .plugin.id = "memory-plugin-v1",
+        .plugin.parse = parse_clb2,
+        .plugin.compile = NULL,
+        .plugin.printer_info = NULL,
+        .plugin.printer_ctree = NULL,
+        .plugin.printer_ptree = NULL,
+        .plugin.node_xpath = NULL,
+        .plugin.snode = NULL,
+        .plugin.validate = NULL,
+        .plugin.pfree = NULL,
+        .plugin.cfree = NULL
+    },
     {0} /* terminating zeroed item */
 };