1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.lang3.builder;
19
20 import static org.junit.jupiter.api.Assertions.assertTrue;
21
22 import org.junit.jupiter.api.Test;
23
24 /**
25 * Tests {@link EqualsBuilder#reflectionEquals(Object, Object, String...)}.
26 * <p>
27 * reflectionEquals array fix enables cyclic-array.
28 * </p>
29 * <p>
30 * Pre-patch: Object[] elements containing themselves cause StackOverflowError when compared via EqualsBuilder.reflectionEquals because the array branch in
31 * reflectionAppend calls append(lhs, rhs) which recurses without cycle check.
32 * </p>
33 * <p>
34 * Post-patch: the arrays are registered before recursing so cycles are detected and the comparison terminates (returning false).
35 * </p>
36 */
37 class EqualsBuilderReflectionEqualsCycleTest {
38
39 @Test
40 void testCrossReferentialObjectArrays() {
41 final Object[] a = new Object[1];
42 final Object[] b = new Object[1];
43 // a[0] -> b, b[0] -> a: mutual cycle
44 a[0] = b;
45 b[0] = a;
46 assertTrue(EqualsBuilder.reflectionEquals(a, b));
47 }
48
49 @Test
50 void testSelfReferentialObjectArrays() {
51 final Object[] a = new Object[1];
52 final Object[] b = new Object[1];
53 a[0] = a;
54 b[0] = b;
55 // Pre-patch: StackOverflowError; Post-patch: terminates without error.
56 // With cycle detection, comparing a[0]=a vs b[0]=b sees (a,b) already registered
57 // and treats the cycle as equal, so the overall result is true (structurally isomorphic).
58 // The key assertion is that NO StackOverflowError is thrown.
59 assertTrue(EqualsBuilder.reflectionEquals(a, b));
60 }
61 }