Maven sub module is not skipped during build - maven

Question

Using maven 3.1.1
In my parent pom I have:
<groupId>com.samples</groupId>
<artifactId>parent</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>pom</packaging>
<name>Parent</name>
<modules>
<module>a</module>
<module>b</module>
<module>c</module>
</modules>
<profiles>
<profile>
<id>skip-c</id>
<modules>
<module>a</module>
<module>b</module>
</modules>
</profile>
...
But module c is still build with I build with:
mvn clean package -Pskip-c
How do I skip a submodule when building my parent project?

Answer 1

Your problem is that your complete module list is always active. You could use a default profile instead.
<groupId>com.samples</groupId>
<artifactId>parent</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>pom</packaging>
<name>Parent</name>
<profiles>
<profile>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<modules>
<module>a</module>
<module>b</module>
<module>c</module>
</modules>
</profile>
<profile>
<id>skip-c</id>
<modules>
<module>a</module>
<module>b</module>
</modules>
</profile>
</profiles>

Answer 2

In addition to julschis comment some details:
Profiles do not replace the normal non profile content of the pom. Therefore, when using your profile, you get a, b and c from the normal pom, and a and b from the profile, therefore your profile is useless.
You need to remove your conditional modules from the main part and put it only into profiles (usually an activeByDefault Profile).
<profile>
<id>default</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<modules>
<module>a</module>
<module>b</module>
</modules>
</profile>
<profile>
<id>add-c</id>
<modules>
<module>a</module>
<module>b</module>
<module>c</module>
</modules>
</profile>
So it is the other way around, profiles cannot remove anything, but only add or override content.
This technique is called reactor pruning and described here: http://www.blackbuild.com/how-to-really-use-maven-profiles-without-endangering-your-karma/
Your could also use the new functionality from https://jira.codehaus.org/browse/MNG-5230, and simply call (this requires Maven 3.2.1+)
mvn clean package -pl !c

Answer 3

Deactivation of profiles can be done using Maven 2.0.10 + .
http://maven.apache.org/guides/introduction/introduction-to-profiles.html
Deactivating a profile
Starting with Maven 2.0.10, one or more profiles can be deactivated using the command line by prefixing their identifier with either the character '!' or '-' as shown below:
mvn groupId:artifactId:goal -P !profile-1,!profile-2
This can be used to deactivate profiles marked as activeByDefault or profiles that would otherwise be activated through their activation config.