THRIFT-5934: Fix deprecated usage of ReflectionProperty::setAccessible() in PHP tests
diff --git a/lib/php/test/Unit/Lib/ReflectionHelper.php b/lib/php/test/Unit/Lib/ReflectionHelper.php
new file mode 100644
index 0000000..5db8741
--- /dev/null
+++ b/lib/php/test/Unit/Lib/ReflectionHelper.php
@@ -0,0 +1,73 @@
+<?php
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+namespace Test\Thrift\Unit\Lib;
+
+trait ReflectionHelper
+{
+    /**
+     * Get a reflection property and make it accessible if needed
+     *
+     * @param object|string $objectOrClass
+     * @param string $propertyName
+     * @return \ReflectionProperty
+     */
+    protected function getAccessibleProperty($objectOrClass, string $propertyName): \ReflectionProperty
+    {
+        $ref = new \ReflectionClass($objectOrClass);
+        $property = $ref->getProperty($propertyName);
+
+        // Only call setAccessible for PHP < 8.1.0
+        if (PHP_VERSION_ID < 80100) {
+            $property->setAccessible(true);
+        }
+
+        return $property;
+    }
+
+    /**
+     * Get the value of a private/protected property
+     *
+     * @param object $object
+     * @param string $propertyName
+     * @return mixed
+     */
+    protected function getPropertyValue($object, string $propertyName)
+    {
+        $property = $this->getAccessibleProperty($object, $propertyName);
+
+        return $property->getValue($object);
+    }
+
+    /**
+     * Set the value of a private/protected property
+     *
+     * @param object $object
+     * @param string $propertyName
+     * @param mixed $value
+     * @return void
+     */
+    protected function setPropertyValue($object, string $propertyName, $value): void
+    {
+        $property = $this->getAccessibleProperty($object, $propertyName);
+        $property->setValue($object, $value);
+    }
+}