Execute Maven plugin goal on parent module, but not on children - version-control

Question

We have a multi-module maven project that uses a profile that defines a buildnumber-maven-plugin to increment a build number and then check it into source control.
If I define the plugin in the parent pom.xml it executes for all the child builds as well.
Here's my parent pom.xml
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.webwars</groupId>
<artifactId>parent</artifactId>
<packaging>pom</packaging>
<properties>
<buildNumber.properties>${basedir}/../parent/buildNumber.properties</buildNumber.properties>
</properties>
<version>1.0-SNAPSHOT</version>
<name>Parent Project</name>
<profiles>
<profile>
<id>release</id>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<debug>false</debug>
<optimize>true</optimize>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>buildnumber-maven-plugin</artifactId>
<version>1.0-beta-3</version>
<executions>
<execution>
<phase>validate</phase>
<goals>
<goal>create</goal>
</goals>
</execution>
</executions>
<configuration>
<buildNumberPropertiesFileLocation>${buildNumber.properties}</buildNumberPropertiesFileLocation>
<getRevisionOnlyOnce>true</getRevisionOnlyOnce>
<doCheck>false</doCheck>
<doUpdate>false</doUpdate>
<format>{0, number}</format>
<items>
<item>buildNumber</item>
</items>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-scm-plugin</artifactId>
<executions>
<execution>
<phase>install</phase>
<goals>
<goal>checkin</goal>
</goals>
</execution>
</executions>
<configuration>
<basedir>${basedir}</basedir>
<includes>buildNumber.properties</includes>
<message>[Automated checkin] of ${basedir} Build version: ${major.version}.${minor.version}.${buildNumber}</message>
<developerConnectionUrl>...</developerConnectionUrl>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
<modules>
<module>../common</module>
<module>../data</module>
<module>../client</module>
<module>../webplatform</module>
</modules>
...
</project>

Answer 1

As documented in the Plugins section of the pom reference:
Beyond the standard coordinate of groupId:artifactId:version, there are elements which configure the plugin or this builds interaction with it.
inherited: true or false, whether or not this plugin configuration should apply to POMs which inherit from this one.
So just add <inherited>false</inherited> to the buildnumber-maven-plugin configuration to avoid inheritance in children POMs:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>buildnumber-maven-plugin</artifactId>
<version>1.0-beta-3</version>
<inherited>false</inherited>
...
</plugin>

Answer 2

You can add <inherited>false</inherited> to the plugin configuration to avoid inheritance in children POMs:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>buildnumber-maven-plugin</artifactId>
<version>1.0-beta-3</version>
<inherited>false</inherited>
...
</plugin>
Or, if your plugin has multiple executions, you can control which executions are inherited and which are not by adding the inherited tag to the execution body:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<executions>
<execution>
<id>parent-only</id>
<phase>initialize</phase>
<inherited>false</inherited>
<configuration>
<target>
<echo message="Echoed only by this module."/>
</target>
</configuration>
<goals>
<goal>run</goal>
</goals>
</execution>
<execution>
<id>all-modules</id>
<phase>initialize</phase>
<inherited>true</inherited> <!-- Defaults to true, so you could leave this line out -->
<configuration>
<target>
<echo message="Echoed in this module and each child module."/>
</target>
</configuration>
<goals>
<goal>run</goal>
</goals>
</execution>
</executions>
</plugin>

Answer 3

There is a built-in maven option:
mvn --help
...
-N,--non-recursive Do not recurse into sub-projects

Answer 4

If the plugin is custom one and you have access to plugin MOJO code, you can mark the plugin as aggregator; if the expected behavior is applicable for all projects where plugin is to be used.
As mentioned in Mojo API Specification ,
Flags this Mojo to run it in a multi module way, i.e. aggregate the
build with the set of projects listed as modules.
Example,
#Mojo(name = "createHF", inheritByDefault = false, aggregator = true)
public class CreateHFMojo extends AbstractMojo {
..
public void execute() throws MojoExecutionException, MojoFailureException {
....
}
..
}
Detailed example on github.

Answer 5

Just an addition to the great answers here: note that per-execution inheritance is broken in Maven 2: http://jira.codehaus.org/browse/MNG-3959