From 839da86cac604365747ee785e517029007ca7d96 Mon Sep 17 00:00:00 2001
From: Leonid Yuriev <leo@yuriev.ru>
Date: Tue, 7 Dec 2021 00:14:22 +0300
Subject: [PATCH] mdbx: minor fix handling `MDBX_SET_LOWERBOUND` to avoid
 `MDBX_BAD_VALSIZE`.

Related to https://github.com/erthink/libmdbx/issues/248#issuecomment-986542620.
---
 src/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/core.c b/src/core.c
index 7982e1f7..c36660be 100644
--- a/src/core.c
+++ b/src/core.c
@@ -14517,7 +14517,12 @@ int mdbx_cursor_get(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data,
     rc = csr.err;
     if (rc == MDBX_SUCCESS && csr.exact && mc->mc_xcursor) {
       mc->mc_flags &= ~C_DEL;
-      if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
+      csr.exact = false;
+      if (!save_data.iov_base && (mc->mc_db->md_flags & MDBX_DUPFIXED)) {
+        /* Avoiding search nested dupfixed hive if no data provided.
+         * This is changes the semantic of MDBX_SET_LOWERBOUND but avoid
+         * returning MDBX_BAD_VALSIZE. */
+      } else if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
         *data = save_data;
         csr = mdbx_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL,
                               MDBX_SET_RANGE);