HHH-19725 Test upsert for entity type that only declares an ID attribute

Author: yrodiere

hibernate-core/src/test/java/org/hibernate/orm/test/stateless/UpsertTest.java

@@ -8,9 +8,10 @@
 import org.junit.jupiter.api.Test;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 @SessionFactory
-@DomainModel(annotatedClasses = UpsertTest.Record.class)
+@DomainModel(annotatedClasses = {UpsertTest.Record.class, UpsertTest.IdOnly.class})
 public class UpsertTest {
     @Test void test(SessionFactoryScope scope) {
         scope.inStatelessTransaction(s-> {
@@ -29,7 +30,18 @@ public class UpsertTest {
             assertEquals("hello mars",s.get(Record.class,456L).message);
         });
     }
-    @Entity
+    @Test void testIdOnly(SessionFactoryScope scope) {
+		scope.inStatelessTransaction(s-> {
+			s.upsert(new IdOnly(123L));
+			s.upsert(new IdOnly(456L));
+		});
+		scope.inStatelessTransaction(s-> {
+			assertNotNull(s.get( IdOnly.class,123L));
+			assertNotNull(s.get( IdOnly.class,456L));
+		});
+	}
+
+	@Entity
     static class Record {
         @Id Long id;
         String message;
@@ -42,4 +54,16 @@ static class Record {
         Record() {
         }
     }
+
+	@Entity(name = "IdOnly")
+	static class IdOnly {
+		@Id Long id;
+
+		IdOnly(Long id) {
+			this.id = id;
+		}
+
+		IdOnly() {
+		}
+	}
 }