From 6c2724fc05d12904f8c2f58f8dbadd9523d18c96 Mon Sep 17 00:00:00 2001
From: Alexey Botchkov <holyfoot@askmonty.org>
Date: Mon, 30 Sep 2019 15:27:48 +0400
Subject: [PATCH] MDEV-19628 JSON with starting double quotes key is not valid.

Make the skip_key a bit faster.
---
 strings/json_lib.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/strings/json_lib.c b/strings/json_lib.c
index e09082470e8..d24fab4ddeb 100644
--- a/strings/json_lib.c
+++ b/strings/json_lib.c
@@ -826,7 +826,10 @@ static int skip_key(json_engine_t *j)
 {
   int t_next, c_len;
 
-  j->s.c_str-= j->sav_c_len;
+  if (json_instr_chr_map[j->s.c_next] == S_BKSL &&
+      json_handle_esc(&j->s))
+    return 1;
+
   while (json_read_keyname_chr(j) == 0) {}
 
   if (j->s.error)