Handle non-existent sources

[fabianishere]

Hi,

I recently updated to version of 0.13.1 to be able to upgrade to Gradle v7.5. It seems however that the new worker-based implementation fails when using Kotlin, complaining about non-existent Java class directories. For instance, this is the error is get when using the latest versions in one of my projects:

 Task :opendc-web:opendc-web-proto:jandex
java.nio.file.NoSuchFileException: /Users/fabian/Documents/Workspace/Projects/AtLarge Research/opendc/opendc-web/opendc-web-proto/build/classes/java/main
        at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:92)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
        at java.base/sun.nio.fs.UnixFileAttributeViews$Basic.readAttributes(UnixFileAttributeViews.java:55)
        at java.base/sun.nio.fs.UnixFileSystemProvider.readAttributes(UnixFileSystemProvider.java:148)
        at java.base/java.nio.file.Files.readAttributes(Files.java:1851)
        at java.base/java.nio.file.FileTreeWalker.getAttributes(FileTreeWalker.java:220)
        at java.base/java.nio.file.FileTreeWalker.visit(FileTreeWalker.java:277)
        at java.base/java.nio.file.FileTreeWalker.walk(FileTreeWalker.java:323)
        at java.base/java.nio.file.Files.walkFileTree(Files.java:2805)
        at java.base/java.nio.file.Files.walkFileTree(Files.java:2883)
        at org.kordamp.gradle.plugin.jandex.tasks.JandexWorkAction.execute(JandexWorkAction.groovy:51)

This pull request updates JandexWorkAction to support sources passed to the task that do not actually exist.

By the way, it seems that the jandex task does not fail when JandexWorkAction throws an exception. In my project, Gradle reported the build to have completed successfully, even though JandexWorkAction failed. However, I am not familiar enough with the Gradle Worker API to be able to fix this.

[aalmiray]

Thanks! 😄