in src/main/java/org/apache/maven/plugins/clean/Cleaner.java [287:296]
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
if ((selector == null || selector.matches(file)) && tryDelete(file)) {
if (listDeletedFiles) {
logDelete(file, attrs);
}
} else {
nonEmptyDirectoryLevels.set(currentDepth); // Remember that the directory will not be empty.
}
return FileVisitResult.CONTINUE;
}