From 3303fe2fd3d952eab7a2da1aa936cdab2c0cbfae Mon Sep 17 00:00:00 2001
From: Kseniia Sumarokova <54203879+kssenii@users.noreply.github.com>
Date: Thu, 15 Jul 2021 17:58:58 +0300
Subject: [PATCH] Update ZstdInflatingReadBuffer.cpp

---
 src/IO/ZstdInflatingReadBuffer.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/IO/ZstdInflatingReadBuffer.cpp b/src/IO/ZstdInflatingReadBuffer.cpp
index 7644050c4a5..6c03ea420a9 100644
--- a/src/IO/ZstdInflatingReadBuffer.cpp
+++ b/src/IO/ZstdInflatingReadBuffer.cpp
@@ -58,6 +58,9 @@ bool ZstdInflatingReadBuffer::nextImpl()
     }
     else if (output.pos == 0)
     {
+        /// It is possible, that input buffer is not at eof yet, but nothing was decompressed in current iteration.
+        /// But there are cases, when such behaviour is not allowed - i.e. if input buffer is not eof, then
+        /// it has to be guaranteed that working_buffer is not empty. So if it is empty, continue.
         return nextImpl();
     }