Test for null result in DataIndexer.getOptimalPartialIndex (deephaven#5449)

Author: rcaudy

engine/table/src/main/java/io/deephaven/engine/table/impl/indexer/DataIndexer.java

@@ -252,7 +252,7 @@ public static DataIndex getOptimalPartialIndex(Table table, final String... keyC
                 .filter(Objects::nonNull)
                 .max(Comparator.comparingLong(dataIndex -> dataIndex.table().size()))
                 .orElse(null),
-                table::isRefreshing, DataIndex::isRefreshing);
+                table::isRefreshing, (final DataIndex result) -> result != null && result.isRefreshing());
     }
 
     /**

engine/table/src/test/java/io/deephaven/engine/table/impl/QueryTableWhereTest.java

@@ -318,6 +318,15 @@ private void testWhereInDependencyInternal(
         }
     }
 
+    @Test
+    public void testWhereInOptimalIndexSelectionWithNoneAvailable() {
+        final Table lhs = emptyTable(10).update("Part=ii % 2 == 0 ? `Apple` : `Pie`", "Hello=ii", "Goodbye = `A`+ii");
+        DataIndexer.getOrCreateDataIndex(lhs, "Part");
+        final Table rhs = emptyTable(2).update("Hello=ii", "Goodbye = `A`+ii");
+        final Table result = lhs.whereIn(rhs, "Goodbye");
+        assertTableEquals(lhs.head(2), result);
+    }
+
     @Test
     public void testWhereDynamicIn() {
         final QueryTable setTable = testRefreshingTable(i(2, 4, 6, 8).toTracking(), col("X", "A", "B", "C", "B"));