This is an automated email from the ASF dual-hosted git repository.
ramanathan1504 pushed a commit to branch 2.x
in repository https://gitbox.apache.org/repos/asf/logging-log4j2.git
The following commit(s) were added to refs/heads/2.x by this push:
new 819f2167ca fix: null-check parseAppender result in log4j-1.2-api
XmlConfiguration (#4172)
819f2167ca is described below
commit 819f2167cadfc47645926fe7a0ce52b5b33290f9
Author: Sebastien Tardif <[email protected]>
AuthorDate: Mon Jul 20 12:16:03 2026 -0400
fix: null-check parseAppender result in log4j-1.2-api XmlConfiguration
(#4172)
* fix: null-check parseAppender result in log4j-1.2-api XmlConfiguration
parseAppender can return null when the appender cannot be instantiated.
Dereferencing getName() then caused an NPE during configuration parsing.
Signed-off-by: Sebastien Tardif <[email protected]>
* Address review: warn, null name guard, test, changelog
- Log a warning when parseAppender returns null or getName() is null
- Unit test with invalid appender class that NPE'd without the guard
- Changelog entry for PR 4172
- Sibling parse() cases (parseCategory/parseRoot) are void and already
null-safe; only APPENDER_TAG used a nullable return
* Remove explanatory comments from appender null-guard and test
Address review feedback: drop production and test comments around the
parseAppender null handling.
Signed-off-by: Sebastien Tardif <[email protected]>
---------
Signed-off-by: Sebastien Tardif <[email protected]>
Co-authored-by: Ramanathan <[email protected]>
---
.../org/apache/log4j/xml/XmlConfiguration.java | 16 +++++++++-
.../apache/log4j/config/XmlConfigurationTest.java | 13 ++++++++
.../src/test/resources/log4j1-invalid-appender.xml | 35 ++++++++++++++++++++++
.../.2.x.x/fix_xml_parse_appender_npe.xml | 8 +++++
4 files changed, 71 insertions(+), 1 deletion(-)
diff --git
a/log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java
b/log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java
index a4e7916139..e11e8c4767 100644
--- a/log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java
+++ b/log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java
@@ -774,7 +774,21 @@ public class XmlConfiguration extends Log4j1Configuration {
break;
case APPENDER_TAG:
final Appender appender = parseAppender(currentElement);
- appenderMap.put(appender.getName(), appender);
+ if (appender == null) {
+ LOGGER.warn(
+ "Could not create appender named [{}] of class
[{}]; ignoring.",
+ subst(currentElement.getAttribute(NAME_ATTR)),
+
subst(currentElement.getAttribute(CLASS_ATTR)));
+ break;
+ }
+ final String appenderName = appender.getName();
+ if (appenderName == null) {
+ LOGGER.warn(
+ "Appender of class [{}] has a null name;
ignoring.",
+
subst(currentElement.getAttribute(CLASS_ATTR)));
+ break;
+ }
+ appenderMap.put(appenderName, appender);
addAppender(AppenderAdapter.adapt(appender));
break;
default:
diff --git
a/log4j-1.2-api/src/test/java/org/apache/log4j/config/XmlConfigurationTest.java
b/log4j-1.2-api/src/test/java/org/apache/log4j/config/XmlConfigurationTest.java
index 95a260ed86..8cf5862059 100644
---
a/log4j-1.2-api/src/test/java/org/apache/log4j/config/XmlConfigurationTest.java
+++
b/log4j-1.2-api/src/test/java/org/apache/log4j/config/XmlConfigurationTest.java
@@ -16,9 +16,11 @@
*/
package org.apache.log4j.config;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertInstanceOf;
import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.io.File;
@@ -99,6 +101,17 @@ class XmlConfigurationTest extends
AbstractLog4j1ConfigurationTest {
assertTrue(file.length() > 0, "File A2 is empty");
}
+ @Test
+ void testInvalidAppenderDoesNotNpe() throws Exception {
+ final LoggerContext loggerContext =
+ assertDoesNotThrow(() ->
TestConfigurator.configure("target/test-classes/log4j1-invalid-appender.xml"));
+ final Configuration configuration = loggerContext.getConfiguration();
+ assertNotNull(configuration, "Configuration should still be created");
+ assertNull(configuration.getAppender("bad"), "Invalid appender should
not be registered");
+ final Appender list = configuration.getAppender("list");
+ assertNotNull(list, "Valid list appender should be registered");
+ }
+
@Override
@Test
public void testConsoleEnhancedPatternLayout() throws Exception {
diff --git a/log4j-1.2-api/src/test/resources/log4j1-invalid-appender.xml
b/log4j-1.2-api/src/test/resources/log4j1-invalid-appender.xml
new file mode 100644
index 0000000000..7a77470637
--- /dev/null
+++ b/log4j-1.2-api/src/test/resources/log4j1-invalid-appender.xml
@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ ~ 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.
+ -->
+<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
+
+<!-- Invalid appender class must not NPE during parse(); valid ListAppender
still loads. -->
+<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/";>
+ <appender name="bad" class="org.apache.log4j.DoesNotExistAppender"/>
+
+ <appender name="list" class="org.apache.log4j.ListAppender">
+ <layout class="org.apache.log4j.PatternLayout">
+ <param name="ConversionPattern" value="%m%n" />
+ </layout>
+ </appender>
+
+ <root>
+ <priority value="debug" />
+ <appender-ref ref="list" />
+ </root>
+
+</log4j:configuration>
diff --git a/src/changelog/.2.x.x/fix_xml_parse_appender_npe.xml
b/src/changelog/.2.x.x/fix_xml_parse_appender_npe.xml
new file mode 100644
index 0000000000..d623e40642
--- /dev/null
+++ b/src/changelog/.2.x.x/fix_xml_parse_appender_npe.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
+ xmlns="https://logging.apache.org/xml/ns";
+ xsi:schemaLocation="https://logging.apache.org/xml/ns
https://logging.apache.org/xml/ns/log4j-changelog-0.xsd";
+ type="fixed">
+ <issue id="4172" link="https://github.com/apache/logging-log4j2/pull/4172"/>
+ <description format="asciidoc">Fix NPE in log4j-1.2-api `XmlConfiguration`
when `parseAppender` returns null for an invalid appender element</description>
+</entry>
