From b6ee7918e751d4b45cbb381a5b74a44715ffd6ab Mon Sep 17 00:00:00 2001
From: Andrea Boriero <andrea@hibernate.org>
Date: Wed, 27 Nov 2024 11:50:01 +0100
Subject: [PATCH] HHH-18069 NullPointerException when unioning partition
 results

---
 .../hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java   | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java b/hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java
index 3bd91f0e97..fea924ee63 100644
--- a/hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java
+++ b/hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java
@@ -1982,9 +1982,13 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 		sqmQueryPartStack.push( queryGroup );
 		pushProcessingState( processingState );
 
+		FromClauseIndex firstQueryPartIndex = null;
+		SqlAstProcessingState firstPoppedProcessingState = null;
 		try {
 			newQueryParts.add( visitQueryPart( queryParts.get( 0 ) ) );
 
+			firstQueryPartIndex = lastPoppedFromClauseIndex;
+			firstPoppedProcessingState = lastPoppedProcessingState;
 			collector.setSqmAliasedNodeCollector(
 					(SqmAliasedNodeCollector) lastPoppedProcessingState.getSqlExpressionResolver()
 			);
@@ -2002,6 +2006,8 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 		finally {
 			popProcessingStateStack();
 			sqmQueryPartStack.pop();
+			lastPoppedFromClauseIndex = firstQueryPartIndex;
+			lastPoppedProcessingState = firstPoppedProcessingState;
 		}
 	}