Jar task should merge entries, not create duplicates, at least by default.

For a mystery project, I preferred to take jars from a few upstream java projects and combine them into a single jar for convenient distribution. Following hints on the Gradle Wiki, I created a fourth java project and create a trivial build.gradle consisting essentially of this:

jar {
project.rootProject.subprojects.each( {aproject ->
if ( project != aproject ) { // avoid recursion
aproject.tasks.withType(Jar).each

{archiveTask -> from zipTree( archiveTask.archivePath ) }

}
}
}

This almost works. It does not work in that the resulting jar has 3 or 4 manifests and multiple entries for some directories. Zip allows entries with duplicate names, little did I know.

I suspect this is just an unintended consquence of the recent refactoring of Archive tasks. In any case, I expect, at a minimum, that there would be an easy setting to make "from zipTree" act more like the old Jar merge method. (I couldn't find anything promising in 30 minutes of api/code browsing.) What I really expect is that this would be the default behavior; it must be the 99% case for adding files to jars.

Thanks for your consideration!