From 58fbda0483c3982966339a5e9aa8cb3ee2969fcf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20=C5=81oskot?= <mateusz@loskot.net>
Date: Mon, 23 Nov 2020 21:21:35 +0100
Subject: [PATCH] Avoid dereferencing iterators over empty indexed data values

It seems the values can be empty even if size of blocks
is non-zero (e.g. blocks.size()==1)
---
 include/util/indexed_data.hpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/util/indexed_data.hpp b/include/util/indexed_data.hpp
index 8df3c350a..4c0bb297a 100644
--- a/include/util/indexed_data.hpp
+++ b/include/util/indexed_data.hpp
@@ -331,6 +331,9 @@ template <typename GroupBlockPolicy, storage::Ownership Ownership> struct Indexe
     // Return value at the given index
     ResultType at(std::uint32_t index) const
     {
+        if (values.empty())
+            return ResultType();
+
         // Get block external ad internal indices
         const BlocksNumberType block_idx = index / (BLOCK_SIZE + 1);
         const std::uint32_t internal_idx = index % (BLOCK_SIZE + 1);