tree.diffWorkDir only returns changes to existing files. It does not seem return any new files added. Basically, I want something that will act like git add -A . from the base working directory.

Also, tree.diffWorkDir only seems to work once there's been an initial commit. Is there a better way to add all the files in a directory to the index, than walking recursively through the directory structure and calling index.addByPath for each file?