Fix a bug with projections and the aggregate_functions_null_for_empty

setting (for query_plan_optimize_projection)

Fix a bug with projections and the aggregate_functions_null_for_empty
setting. This was already fixed in PR ClickHouse#42198 but got forgotten after
using query_plan_optimize_projection.

src/Processors/QueryPlan/Optimizations/projectionsCommon.cpp

@@ -42,6 +42,10 @@ bool canUseProjectionForReadingStep(ReadFromMergeTree * reading)
     if (reading->getContext()->getSettingsRef().allow_experimental_query_deduplication)
         return false;
 
+    // Currently projection don't support settings which implicitly modify aggregate functions.
+    if (reading->getContext()->getSettingsRef().aggregate_functions_null_for_empty)
+        return false;
+
     return true;
 }
 

tests/queries/0_stateless/01710_projection_aggregate_functions_null_for_empty.reference

@@ -0,0 +1 @@
+1554690688

tests/queries/0_stateless/01710_projection_aggregate_functions_null_for_empty.sql

@@ -0,0 +1,8 @@
+DROP TABLE IF EXISTS t1;
+
+CREATE TABLE t1 (c0 Int32, PRIMARY KEY (c0)) ENGINE=MergeTree;
+INSERT INTO t1 VALUES (1554690688);
+
+SELECT MIN(t1.c0) FROM t1 SETTINGS aggregate_functions_null_for_empty = 1;
+
+DROP TABLE IF EXISTS t1;