Fix NPE in empty BitmapIndices

Author: fh-ms

gigamap/gigamap/src/main/java/org/eclipse/store/gigamap/types/BitmapIndices.java

@@ -701,13 +701,25 @@ public final void ensureOptimizedPerformance()
 		@Override
 		public void internalPrepareIndicesUpdate(final E replacedEntity)
 		{
+			if(this.bitmapIndices.isEmpty())
+			{
+				// no-op
+				return;
+			}
+
 			// Derive state handlers for the state of the replaced entity.
 			this.createChangeHandlers(this.cachedPrevChangeHandlers, replacedEntity);
 		}
 
 		@Override
 		public void internalFinishIndicesUpdate()
 		{
+			if(this.bitmapIndices.isEmpty())
+			{
+				// no-op
+				return;
+			}
+
 			this.clearCachedChangeHandlers();
 		}
 
@@ -719,6 +731,12 @@ public final void internalUpdateIndices(
 			final CustomConstraints<? super E> customConstraints
 		)
 		{
+			if(this.bitmapIndices.isEmpty())
+			{
+				// no-op
+				return;
+			}
+
 			try
 			{
 				// Derive state handlers for the new, potentially changed state

gigamap/gigamap/src/test/java/org/eclipse/store/gigamap/indexer/BasicIndexerTest.java

@@ -287,6 +287,14 @@ void update()
 		assertEquals(0, map.query(indexer).in(1L, 5L).count());
 	}
 
+	@Test
+	void setWithNoIndex()
+	{
+		final GigaMap<String> map = GigaMap.New();
+		final long id = map.add("foo");
+		assertEquals("foo", map.set(id, "bar"));
+	}
+
 	@Test
 	void bulk()
 	{