This is an automated email from the ASF dual-hosted git repository. rmaucher pushed a commit to branch 11.0.x in repository https://gitbox.apache.org/repos/asf/tomcat.git
commit 9b8699badf9c4488796eea7a1f7c0eaf63c7fce7 Author: opencode <[email protected]> AuthorDate: Wed Oct 14 17:14:02 2026 +0200 Emit a null literal for missing CallMethodRule code-gen parameters A CallMethodRule collecting two or more parameters passes a parameter whose nested element is absent to the target method as a null value. That is documented behaviour, and the method call itself handles it. The code generation block at the end of end() did not. A null parameter is not a String, so it was handed to Digester.toVariableName() to name a variable for it. That method registers the object and then dereferences it, so the generated code path aborted the parse with a NullPointerException, wrapped in a SAXException, as soon as a multi-parameter element omitted one of its parameter children, for example an init-param without an init-value. This affects the opt-in -generateCode path used to pre-compile descriptor processing. Emit the null literal for a null parameter instead. The generated statement then reflects the call that is actually made. All first-party targets of these rules declare a single method of that name, so the generated source resolves to the same method the reflective invocation selected; a cast is not needed and would require canonicalising type names for no first-party benefit. --- .../tomcat/util/digester/CallMethodRule.java | 7 ++ .../tomcat/util/digester/TestCallMethodRule.java | 98 ++++++++++++++++++++++ 2 files changed, 105 insertions(+) diff --git a/java/org/apache/tomcat/util/digester/CallMethodRule.java b/java/org/apache/tomcat/util/digester/CallMethodRule.java index c475df0ebe..1f2cb4f37f 100644 --- a/java/org/apache/tomcat/util/digester/CallMethodRule.java +++ b/java/org/apache/tomcat/util/digester/CallMethodRule.java @@ -352,6 +352,13 @@ public class CallMethodRule extends Rule { } if (bodyText != null) { code.append("\"").append(IntrospectionUtils.escape(bodyText)).append("\""); + } else if (paramValues[i] == null) { + // Missing parameters are passed to the method as null + // values. Emit the literal rather than trying to name a + // variable for an object that does not exist. The + // generated call assumes the target method resolves + // unambiguously for a null argument. + code.append("null"); } else if (paramValues[i] instanceof String) { code.append("\"").append(IntrospectionUtils.escape(paramValues[i].toString())).append("\""); } else { diff --git a/test/org/apache/tomcat/util/digester/TestCallMethodRule.java b/test/org/apache/tomcat/util/digester/TestCallMethodRule.java new file mode 100644 index 0000000000..43510aff83 --- /dev/null +++ b/test/org/apache/tomcat/util/digester/TestCallMethodRule.java @@ -0,0 +1,98 @@ +/* + * 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.tomcat.util.digester; + +import java.io.StringReader; + +import org.junit.Assert; +import org.junit.Test; + +import org.xml.sax.InputSource; + +public class TestCallMethodRule { + + public static class TwoArgBean { + + private String first; + private String second; + private int calls; + + public void setTwo(String first, String second) { + this.first = first; + this.second = second; + calls++; + } + + public String getFirst() { + return first; + } + + public String getSecond() { + return second; + } + + public int getCalls() { + return calls; + } + } + + + private static Digester createDigester() { + Digester digester = new Digester(); + digester.addObjectCreate("root", TwoArgBean.class.getName()); + digester.addCallMethod("root/call", "setTwo", 2); + // Only the first parameter has a nested element. The second one is + // legitimately missing and is passed to the method as null. + digester.addCallParam("root/call/first", 0); + return digester; + } + + + @Test + public void testMissingParameterIsPassedAsNull() throws Exception { + Digester digester = createDigester(); + + TwoArgBean bean = (TwoArgBean) digester + .parse(new InputSource(new StringReader("<root><call><first>x</first></call></root>"))); + + Assert.assertEquals(1, bean.getCalls()); + Assert.assertEquals("x", bean.getFirst()); + Assert.assertNull(bean.getSecond()); + } + + + /* + * Code generation must render a missing (null) parameter as the null + * literal rather than generating a variable name for it, which previously + * failed with a NullPointerException. + */ + @Test + public void testGenerateCodeWithMissingParameter() throws Exception { + Digester digester = createDigester(); + + digester.startGeneratingCode(); + TwoArgBean bean = (TwoArgBean) digester + .parse(new InputSource(new StringReader("<root><call><first>x</first></call></root>"))); + String code = digester.getGeneratedCode().toString(); + digester.endGeneratingCode(); + + Assert.assertEquals(1, bean.getCalls()); + Assert.assertNull(bean.getSecond()); + Assert.assertTrue("Generated code was: " + System.lineSeparator() + code, + code.contains(".setTwo(\"x\", null);")); + } +} --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
