maven-clean-plugin is not removing all given directories

In my project .pom I set up the maven-clean-plugin like so:

<plugin>
  <artifactId>maven-clean-plugin</artifactId>
  <version>2.6.1</version>
  <configuration>
    <filesets>
      <fileset>
        <directory>src/main/webapp/bower_components</directory>
      </fileset>
      <fileset>
        <directory>node_modules</directory>
      </fileset>
      <fileset>
        <directory>node</directory>
      </fileset>
    </filesets>
  </configuration>
 </plugin>

The plugin purpose is to remove directories which are created by frontend-maven-plugin. Anyway the last one works OK.

---

Problem

Now the issue is that for no reason, one of the above folders is never removed. And it is always the one "in the middle". I added 3 filesets and always the 2nd one is not removed, see logs:

[INFO] Deleting /src/main/webapp/bower_components (includes = [], excludes = [])
[INFO] Deleting /node_modules (includes = [.bindings], excludes = [])
[INFO] Deleting /node (includes = [], excludes = [])

If I change folders' order:

[INFO] Deleting /src/main/webapp/bower_components (includes = [], excludes = [])
[INFO] Deleting /node (includes = [.bindings], excludes = [])
[INFO] Deleting /node_modules (includes = [], excludes = [])

And also the 2nd option always contains this part: includes = [.bindings] which I believe results in the folder not being deleted.

Why is that happening, and how to fix it?

---

EDIT, debug log

mvn -X clean result, I think this is where it breaks:

http://pastebin.com/ep1i2Bjk

After parsing the pom.xml it reads the configuration with this parameter. However, I did not put it there.

OK I have found the issue! It is actually a bug in the plugin and is already reported. It affects the maven-clean-plugin 2.6.1.

It was my side misconfiguration, read on for the resolution.

Situation

You have a parent project and a child project, both have to use the plugin.

Now;

• in parent project you specify some filesets.
• in child project you specify some filesets.

---

What I think is expected:

Plugin read both parent's and child's filesets and cleans them all.

What happens:

Plugin OVERRIDES the parent's filesets with child's filesets. Filesets are overriden in order. HOWEVER the parents configuration for the fileset is not cleared!

---

My situation: Parent .pom:

<filesets>
   <fileset>
      <directory>test-output</directory>
   </fileset>
   <fileset>
     <directory>${basedir}/</directory>
     <includes>
        <include>.bindings</include>
     </includes> 
   </fileset>
</filesets>

Childs pom:

<filesets>
    <fileset>
        <directory>node</directory>
    </fileset>
    <fileset>
        <directory>node_modules</directory>
    </fileset>
    <fileset>
        <directory>src/main/webapp/bower_components</directory>
    </fileset>
</filesets>

And with the above information; the config read by plugin is:

<filesets>
    <fileset>
        <directory>node</directory>
    </fileset>
    <fileset>
        <directory>node_modules</directory>
        <includes>
            <include>.bindings</include>
        </includes>
    </fileset>
    <fileset>
        <directory>src/main/webapp/bower_components</directory>
    </fileset>
</filesets>

instead of a config with 5 filesets.

Bug report https://issues.apache.org/jira/browse/MCLEAN-64

RESOLVED

For configuration there are some magic attributes to instruct how xml elements should be combined. In this case add combine.children="append" to the filesets tag. More details about this can be found on the POM Reference page. http://maven.apache.org/pom.html

Worth mentioning is that it is enough to set combine.children="append" in child's project .pom.