Any news on a possible fix?? It's been 3 weeks now without an update.

When I build submodules one by one, they produce correct ZIPs.
But when i build the entire project with all submodules, their ZIPs contain duplicated entries.

I found this bug while trying to merge 2 <fileset> directories expecting that the 2nd would overwrite the first set of files where they overlap (in using one fileset as "default" files and the 2nd fileset as overrides).

The result was as described in the bug - 2 identical files added to the resulting zip file. Upon extraction of the zip, I was prompted for an option to override one of the files. I also verified that the case on both files was lower case, so its NOT an issue with the same filename with different case; ie creating the archive on unix and extracting on Windows.

This bug has been open for a long time. It would be appreciated if this was fixed ASAP. Its a huge blocker. Thanks!

example assembly.xml file:

<assembly 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/assembly-1.1.0-SNAPSHOT.xsd">

<id>bin</id>

<formats>
<format>zip</format>
</formats>

<fileSets>
<fileSet>
<!--must use absolute reference with ${pom.basedir} to achieve filtering -->
<directory>${pom.basedir}/src/main/config/defaults/</directory>
<outputDirectory>${pom.basedir}/target/work/</outputDirectory>
<filtered>true</filtered>
</fileSet>
<fileSet>
<!-- must use absolute reference with ${pom.basedir} to achieve filtering -->
<directory>${pom.basedir}/src/main/config/overrides/</directory>
<outputDirectory>${pom.basedir}/target/work/</outputDirectory>
<filtered>true</filtered>
</fileSet>
</fileSets>

</assembly>

Until this is fixed, here is an example work around, if you are interested (the modules parent is a default jboss-assembly module - the child module inherits the src and config of the default jboss-assembly):

pom.xml:

<plugins>

<!-- generate resources. merge default and current configurations. -->
<plugin>
<artifactId>maven-antrun-plugin</artifactId>
<executions>
<execution>
<phase>generate-resources</phase>
<configuration>
<tasks>
<copy todir="${project.build.directory}/generated-resources/"
preservelastmodified="true" verbose="true" overwrite="true">
<fileset dir="${basedir}/../jboss-assembly/src/main/config/"/>
</copy>
<copy todir="${project.build.directory}/generated-resources/"
preservelastmodified="true" verbose="true" overwrite="true">
<fileset dir="${basedir}/src/main/config/"/>
</copy>
</tasks>
</configuration>
<goals>
<goal>run</goal>
</goals>
</execution>
</executions>
</plugin>

<-- maven assembly plugin -->
</plugins>

<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2-beta-3-SNAPSHOT</version>
<configuration>
<archiverConfig>
<duplicateBehaviour>skip</duplicateBehaviour>
</archiverConfig>
<descriptors>
<descriptor>src/main/assembly/assembly.xml</descriptor>
</descriptors>
<outputDirectory>target</outputDirectory>
</configuration>
</plugin>

used in multimodule project (parent, then few modules as child), this is still adding duplicates into the final ZIP archive. <duplicateBehaviour>fail</duplicateBehaviour> does not fail as well.

I will appreciate any help.

Why should we try to preserve incorrect behaviour? This sort of thing cripples products - just look at the www.

Please point it out if there's something I'm missing.

Shouldn't the default behaviour be the 'correct' behaviour?

+1, following Maven's spirit of "convention over configuration" where the convention of course should be sensible, i.e. cover the major use case.

Have opened a new issue to cover this, as this one has been officially closed and doesn't seem to be getting much attention:
http://jira.codehaus.org/browse/MASSEMBLY-361

Please go and vote for it!

In terms of two fileSets, however, it makes sense to allow overwrites. Since this is pretty complex to implement in plexus-archiver, I'll create a new issue for it and assign it to 2.2 (final).