Investigated using the OSX fsevents API to detect when files are modified, so they can be committed when using direct mode. There's a haskell library and even a sample directory watching program. Initial tests look good...

Using fsevents will avoid kqueue's problems with needing enough file descriptors to open every subdirectory. kqueue is a rather poor match for git-annex's needs, really. It does not seem to provide events for file modifications at all, unless every file is individually opened. While I dislike leaving the BSD's out, they need a better interface to be perfectly supported by git-annex, and kqueue will still work for indirect mode repositories.

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Got the assistant to use fsevents. It seems to work well!

The only problem I know of is that it doesn't yet handle whole directory renames. That should be easy to fix later.