There is now multiple build WARNING output on every use of `exportAntProperties` as of 3.2.0

[jbindel]

Affected version

3.2.0

Bug description

There is now WARNING output on every use of exportAntProperties

Because all maven properties are imported to ant tasks, all properties will get a WARNING output in the build that uses the AntRun plugin and exports properties from the Ant task.

The cause of this is a change to the logging level from the original, expected DEBUG level to its current WARNING level.

maven-antrun-plugin/src/main/java/org/apache/maven/plugins/antrun/AntRunMojo.java

Line 465 in 629e579

getLog().warn("Ant property '" + key + "=" + mavenProperties.getProperty(key)

Expected: Using the exportAntProperties with value of true should not generate WARNING output in a Maven build.
Actual: The build outputs a warning for every existing Maven property that is set.

It may be acceptable and useful to output a warning if the value of the Ant property and the value of an existing Maven property do not match as that would indicate something odd.

[cortlepp]

I have the same issue/annoyance, it would be really nice if we could get this resolved. Especially since @jbindel already went through the trouble and implemented a fix in #349 . The CI of that PR is failing currently, but from the log messages this looks like a temporary network problem, so it should be fixed by merely restarting the checks.

[haxorof]

Just for connecting the issues which caused the mentioned change: #108 (#201).

So now when you have many properties it will be a lot of warnings by default which is not nice at all to have in your Maven output. With the current implemention it would have been workable if some plugin configuration was added to get back to the old behavior or skip that logging completely since it was only visible on debug before.

[cortlepp]

(Friendly ping @elharo 🙂)

[clafren1]

In the open PR, it may not be necessary to do a value comparison between the ANT property and the corresponding Maven property, if it exists.

Based on a simple test, it doesn't seem possible to override a Maven property from the antrun plugin, even with the <local> task.

This sample POM demonstrates the immutable behavior:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>my.groupId</groupId>
  <artifactId>my-artifactId</artifactId>
  <version>1.0</version>
  <packaging>pom</packaging>
  <properties>
    <some.property>maven</some.property>
  </properties>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <version>3.2.0</version>
        <executions>
          <execution>
            <id>print-property</id>
            <phase>verify</phase>
            <goals>
              <goal>run</goal>
            </goals>
            <configuration>
              <target>
                <echo level="info">some.property (maven): ${some.property}</echo>
                <property name="some.property" value="ant"/>
                <echo level="info">some.property (ant): ${some.property}</echo>
                <local name="some.property"/>
                <property name="some.property" value="local"/>
                <echo level="info">some.property (local): ${some.property}</echo>
              </target>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

The console output from running mvn clean verify with Maven 3.9.11 is:

[INFO]      [echo] some.property (maven): maven
[INFO]      [echo] some.property (ant): maven
[INFO]      [echo] some.property (local): maven

some.property is defined as a POM property and its value remains constant despite the <property> & <local> ANT tasks.

Alternative ways to remove the unwanted warnings could be:

• revert the log message back to debug, as the log level change had no obvious link to the limitation that needed to be documented in the original issue
• completely ignore ANT properties that are also Maven properties during the export step, as their values can not be changed with this plugin

[gtaylor1981]

This added nearly 400 warnings to my build output, is there any way around this?

[clafren1]

This message can expose sensitive information, as properties defined in the user settings.xml file also become ANT properties and trigger the warning, with the property value being interpolated.

To be fair, it could also occur with the previous log level if you ran Maven in debug mode. But a warning is much more visible.

At the very least, the property value should not be logged.

I'm still not convinced a message is even necessary, regardless of the log level.

To expand on my previous comment, consider this new sample POM:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>my.groupId</groupId>
  <artifactId>my-artifactId</artifactId>
  <version>1.0</version>
  <packaging>pom</packaging>
  <profiles>
    <profile>
      <id>nashorn</id>
      <activation>
        <jdk>[11,(</jdk>
      </activation>
      <build>
        <plugins>
          <plugin>
            <artifactId>maven-antrun-plugin</artifactId>
            <dependencies>
              <dependency>
                <groupId>org.openjdk.nashorn</groupId>
                <artifactId>nashorn-core</artifactId>
                <version>15.7</version>
              </dependency>
            </dependencies>
          </plugin>
        </plugins>
      </build>
    </profile>
    <profile>
      <id>maven</id>
      <properties>
        <my.property>maven</my.property>
      </properties>
    </profile>
  </profiles>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <version>3.2.0</version>
        <executions>
          <execution>
            <id>print-property</id>
            <phase>verify</phase>
            <goals>
              <goal>run</goal>
            </goals>
            <configuration>
              <target>
                <condition property="my.property" value="ant">
                  <not>
                    <isset property="my.property"/>
                  </not>
                </condition>
                <echo level="info">my.property (init): ${my.property}</echo>
                <available file="${basedir}/pom.xml" property="my.property" value="available"/>
                <echo level="info">my.property (available task): ${my.property}</echo>
                <script language="javascript">project.setProperty("my.property", "script");</script>
                <echo level="info">my.property (script task): ${my.property}</echo>
                <taskdef name="groovy" classname="org.codehaus.groovy.ant.Groovy"/>
                <groovy>properties['my.property'] = 'groovy'</groovy>
                <echo level="info">my.property (groovy task): ${my.property}</echo>
                <local name="my.property"/>
                <property name="my.property" value="local"/>
                <echo level="info">my.property (local task): ${my.property}</echo>
              </target>
            </configuration>
          </execution>
        </executions>
        <dependencies>
          <dependency>
            <groupId>org.apache.groovy</groupId>
            <artifactId>groovy-ant</artifactId>
            <version>4.0.32</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

The available task is 1 of the very few built-in ANT tasks that can override an existing property.

It uses org.apache.tools.ant.Project#setProperty instead of org.apache.tools.ant.Project#setNewProperty.

I assume the groovy task also uses it internally with properties['name'] = 'value' statements.

When you run mvn clean verify, which initializes the my.property property in the antrun plugin with the condition task, you get:

[INFO]      [echo] my.property (init): ant
[WARNING] [available] DEPRECATED - <available> used to override an existing property.
[available]   Build file should not reuse the same property name for different values.
[INFO]      [echo] my.property (available task): available
[INFO]      [echo] my.property (script task): script
[INFO]      [echo] my.property (groovy task): groovy
[INFO]      [echo] my.property (local task): local

However, when you run mvn clean verify -Pmaven, which initializes the my.property property in the maven profile, you get:

[INFO]      [echo] my.property (init): maven
[WARNING] [available] DEPRECATED - <available> used to override an existing property.
[available]   Build file should not reuse the same property name for different values.
[INFO]      [echo] my.property (available task): maven
[INFO]      [echo] my.property (script task): maven
[INFO]      [echo] my.property (groovy task): maven
[INFO]      [echo] my.property (local task): maven

You get a similar output if you run mvn clean verify -Dmy.property=maven.

Or if my.property is defined in your settings.xml file and you run mvn clean verify.

I can't think of other ways to override a property in ANT.

If the maven-antrun-plugin maintainers can confirm/explain this immutable behavior, would it be okay to simply remove the message?

[clafren1]

Hi @slawekjaranowski , @Bukama, @slachiewicz
sorry for tagging you directly but as the 3 most active maven-antrun-plugin committers over the past 12 months, could one of you comment on this issue whenever you have a few minutes?

The author of the problematic code was pinged last December but has yet to acknowledge.

Thank you for your insights.

[elharo]

gemini found something important here:

Problem Analysis

In version 3.2.0 of maven-antrun-plugin, the log level for exporting Ant properties back to Maven was changed from DEBUG to WARN. When <exportAntProperties> is enabled, every Maven property passed into the Ant execution triggers a WARN-level log entry upon completion.

This change causes two main problems:

1. Log Spam: Projects with numerous Maven properties produce hundreds of warning messages during standard builds, obscuring genuine issues.
2. Security/Information Exposure: WARN messages display property keys and their interpolated string values in plain text. Any sensitive credentials (such as tokens or passwords defined in settings.xml or properties) are exposed at standard build verbosity levels.

---

Recommended Solution

To resolve the issue correctly, the plugin maintainers should implement the following changes:

1. **Revert the Log Level to DEBUG**: Re-exporting existing properties is part of the standard execution path and does not indicate an error or misconfiguration. Changing getLog().warn(...) back to getLog().debug(...) eliminates build log noise and prevents sensitive value exposure at standard log levels.
2. Compare Property Values Before Logging: If a warning is intended to alert users about overridden properties, the plugin should compare the Ant property value with the pre-existing Maven property value. A warning should only be generated when a value actually changes.
3. Omit Property Values from Warning Logs: If any warning condition is retained, it should log only the property key name rather than the value itself to avoid leaking sensitive data into build outputs.