From 9fc51aef683004d059094ebc946003b0870246c7 Mon Sep 17 00:00:00 2001
From: Alexander Kuzmenkov <akuzm@yandex-team.ru>
Date: Thu, 27 May 2021 21:39:06 +0300
Subject: [PATCH] fix

---
 src/AggregateFunctions/AggregateFunctionFactory.cpp        | 6 ++++--
 tests/queries/0_stateless/01591_window_functions.reference | 2 ++
 tests/queries/0_stateless/01591_window_functions.sql       | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/AggregateFunctions/AggregateFunctionFactory.cpp b/src/AggregateFunctions/AggregateFunctionFactory.cpp
index 17c3974390b..d0e45053695 100644
--- a/src/AggregateFunctions/AggregateFunctionFactory.cpp
+++ b/src/AggregateFunctions/AggregateFunctionFactory.cpp
@@ -92,8 +92,10 @@ AggregateFunctionPtr AggregateFunctionFactory::get(
 
         // Pure window functions are not real aggregate functions. Applying
         // combinators doesn't make sense for them, they must handle the
-        // nullability themselves.
-        if (nested_function->asWindowFunction())
+        // nullability themselves. Another special case is functions from Nothing
+        // that are rewritten to AggregateFunctionNothing, in this case
+        // nested_function is nullptr.
+        if (nested_function && nested_function->asWindowFunction())
         {
             return nested_function;
         }
diff --git a/tests/queries/0_stateless/01591_window_functions.reference b/tests/queries/0_stateless/01591_window_functions.reference
index 5bbcd28d79b..c5ea5183020 100644
--- a/tests/queries/0_stateless/01591_window_functions.reference
+++ b/tests/queries/0_stateless/01591_window_functions.reference
@@ -1058,6 +1058,8 @@ settings max_block_size = 3;
 select lagInFrame(toNullable(1)) over ();
 0
 select lagInFrameOrNull(1) over (); -- { serverError 36 }
+select intDiv(1, NULL) x, toTypeName(x), max(x) over ();
+\N	Nullable(Nothing)	\N
 -- case-insensitive SQL-standard synonyms for any and anyLast
 select
     number,
diff --git a/tests/queries/0_stateless/01591_window_functions.sql b/tests/queries/0_stateless/01591_window_functions.sql
index 458dfb7393e..f0bfc2c842a 100644
--- a/tests/queries/0_stateless/01591_window_functions.sql
+++ b/tests/queries/0_stateless/01591_window_functions.sql
@@ -379,6 +379,7 @@ settings max_block_size = 3;
 -- careful with auto-application of Null combinator
 select lagInFrame(toNullable(1)) over ();
 select lagInFrameOrNull(1) over (); -- { serverError 36 }
+select intDiv(1, NULL) x, toTypeName(x), max(x) over ();
 
 -- case-insensitive SQL-standard synonyms for any and anyLast
 select