Added index bounds check

Author: alex268

query/src/main/java/tech/ydb/query/tools/QueryReader.java

@@ -176,8 +176,12 @@ public int getRowCount() {
 
         @Override
         public void setRowIndex(int index) {
+            if (index < 0 || index >= rowsCount) {
+                throw new IndexOutOfBoundsException(String.format("Index %s out of bounds for length %s",
+                        index, rowsCount));
+            }
             partIndex = 0;
-            int currentIdx = Math.max(index, 0);
+            int currentIdx = index;
             while (partIndex < parts.length) {
                 int readerRows = parts[partIndex].getRowCount();
                 if (currentIdx < readerRows) {
@@ -189,9 +193,6 @@ public void setRowIndex(int index) {
                 partIndex++;
             }
 
-            if (partIndex >= parts.length) {
-                partIndex = parts.length - 1;
-            }
             for (int partStep = partIndex + 1; partStep < parts.length; partStep++) {
                 parts[partStep].setRowIndex(0);
             }

query/src/test/java/tech/ydb/query/tools/QueryReaderTest.java

@@ -142,11 +142,11 @@ public void compositeResultSetTest() {
         rsr.setRowIndex(5);
         Assert.assertEquals(1, readAll(rsr, 5));
 
-        rsr.setRowIndex(6); // after end
-        Assert.assertEquals(0, readAll(rsr, 0));
+        IndexOutOfBoundsException ex1 = Assert.assertThrows(IndexOutOfBoundsException.class, () -> rsr.setRowIndex(6));
+        Assert.assertEquals("Index 6 out of bounds for length 6", ex1.getMessage());
 
-        rsr.setRowIndex(-1); // before start
-        Assert.assertEquals(6, readAll(rsr, 0));
+        IndexOutOfBoundsException ex2 = Assert.assertThrows(IndexOutOfBoundsException.class, () -> rsr.setRowIndex(-1));
+        Assert.assertEquals("Index -1 out of bounds for length 6", ex2.getMessage());
     }
 
     private int readAll(ResultSetReader rsr, int startKey) {