fileSets in maven-assembly-plugin not working when iso9660-maven-plugin is used as archiver

[rbi]

How to reproduce

• Use fileSets with maven-assembly-plugin 3.1.1
• use iso9660-maven-plugin 2.0.1 as archiver to let the assembly-plugin create ISOs.
• See attached Demo project

What happened

• Build fails with an exception "Caused by: com.github.stephenc.javaisotools.sabre.HandlerException: Joliet: Empty directory name encountered."
• see attachment

What should happen

• no exception

Analysis

• When specifying outputDirectory in a fileSet the assembly plugin attaches a trailing / to the directory name. E.g. <outputDirectory>someDir</outputDirectory> gets someDir/
• This line tries to extract the name of the child directory. E.g. it tries to convert someParent/someDir to someDir
• When the child ends with a slash however the method transforms someDir/ to an empty String instead of someDir as it would be expected.

Attachements

exception.log
maven-project.zip