Maven plugin CLI parameter overwriting <configuration> in pom.xml

Question

How does/should Maven plugins behave with regards to the order in which they process configuration options? I would expect that properties passed via CLI overwrite those defined in a <configuration> block in pom.xml .

Here's an example.

pom.xml

<plugin>
    <groupId>group</groupId>
    <artifactId>artifact</artifactId>
    <version>1.2.3</version>
    <executions>
    ...
    </executions>
    <configuration>
        <url>foo.com</url>
    </configuration>
</plugin>

CLI

mvn group:artifact:1.2.3:doit -Dmymojo.url=bar.com

I am currently debugging a plugin (not mine) that gives precedence to the url value defined in the POM rather than the one passed on the CLI. Is that how mojos are supposed to behave ie a Maven feature rather than a plugin bug? I didn't find anything mentioned in the ref guide.

Answer 1

As per https://issues.apache.org/jira/browse/MNG-4979 this works as designed. I find it counter-intuitive and don't find the reasons given in MNG-4979 convincing.

If your setup allows to modify the pom.xml you can work around this behavior as suggested by JF Meier (and the issue above).

<properties>
  <mymojo.url>foo.bar</mymojo.url>
</properties>

<plugin>
    <groupId>group</groupId>
    <artifactId>artifact</artifactId>
    <version>1.2.3</version>
    <executions>
    ...
    </executions>
    <configuration>
        <url>${mymojo.url}</url>
    </configuration>
</plugin>

Answer 2

Through the command line, you set a property url . This would override an entry <url>foo.com</url> in the <properties> section of the POM.

Many plugins allow to set configuration entries through properties, but these properties do not automatically have the same name. In the documentation, this is usually called user property . To see examples, look eg at

https://maven.apache.org/plugins/maven-dependency-plugin/get-mojo.html