zhuxiangyi commented on code in PR #10144: URL: https://github.com/apache/paimon/pull/10144#discussion_r4089701844
########## paimon-flink/paimon-flink-common/src/test/java/org/apache/paimon/flink/NestedFieldReferencesTest.java: ########## @@ -0,0 +1,107 @@ +/* + * 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. + */ + +package org.apache.paimon.flink; + +import org.junit.jupiter.api.Test; + +import java.lang.reflect.Method; +import java.net.URL; +import java.net.URLClassLoader; + +import static org.assertj.core.api.Assertions.assertThat; +import static org.assertj.core.api.Assertions.assertThatCode; + +/** Tests for {@link NestedFieldReferences}. */ +public class NestedFieldReferencesTest { + + private static final String HIDDEN = + "org.apache.flink.table.expressions.NestedFieldReferenceExpression"; + + /** + * Flink only has the nested field reference from 1.19 on, but this module is compiled once and + * bundled for Flink 1.16 to 1.18 as well. Loaded where the class is absent, asking whether an + * expression is a nested reference must answer no rather than fail to link. + */ + @Test + public void testAnswersNoWhenTheExpressionIsNotOnTheClasspath() throws Exception { + try (URLClassLoader withoutNestedReferences = hidingClassLoader()) { + Class<?> loaded = + withoutNestedReferences.loadClass(NestedFieldReferences.class.getName()); + assertThat(loaded.getClassLoader()).isSameAs(withoutNestedReferences); + + Method isNestedFieldReference = + loaded.getMethod( + "isNestedFieldReference", + withoutNestedReferences.loadClass( + "org.apache.flink.table.expressions.Expression")); + + // A real expression, not null: `null instanceof X` answers without ever resolving X, + // so only a non-null argument exercises the class the guard has to keep away. + Object expression = + withoutNestedReferences + .loadClass("org.apache.flink.table.expressions.ValueLiteralExpression") + .getConstructor(Object.class) + .newInstance(1); + + assertThatCode(() -> isNestedFieldReference.invoke(null, expression)) + .doesNotThrowAnyException(); + assertThat(isNestedFieldReference.invoke(null, expression)).isEqualTo(false); + } + } + + /** Loads this module's own classes itself, and pretends the nested reference does not exist. */ + private static URLClassLoader hidingClassLoader() { + URLClassLoader appLoader = (URLClassLoader) buildClassPathLoader(); + return new URLClassLoader(appLoader.getURLs(), appLoader.getParent()) { + @Override + protected Class<?> loadClass(String name, boolean resolve) + throws ClassNotFoundException { + if (name.equals(HIDDEN)) { + throw new ClassNotFoundException(name); + } + if (name.startsWith("org.apache.paimon.flink.NestedFieldReferences")) { + synchronized (getClassLoadingLock(name)) { + Class<?> loaded = findLoadedClass(name); + if (loaded == null) { + loaded = findClass(name); + } + if (resolve) { + resolveClass(loaded); + } + return loaded; + } + } + return super.loadClass(name, resolve); + } + }; + } + + private static ClassLoader buildClassPathLoader() { + String[] entries = System.getProperty("java.class.path").split(java.io.File.pathSeparator); + URL[] urls = new URL[entries.length]; + for (int i = 0; i < entries.length; i++) { + try { + urls[i] = new java.io.File(entries[i]).toURI().toURL(); + } catch (Exception e) { + throw new RuntimeException(e); + } + } + return new URLClassLoader(urls, ClassLoader.getPlatformClassLoader()); Review Comment: Thanks, you were right and the fix is in `81ac2b5`. Reproduced it locally with javac 1.8 and got your exact error, then switched to `ClassLoader.getSystemClassLoader().getParent()` as you suggested. The same javac now compiles the file, and removing the guard in `NestedFieldReferences` still makes the test fail with `NoClassDefFoundError`, so the Java 8 fix did not weaken what it checks. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
