`createDirectoryIfMissing True` creates any missing parent directories.
So if the git repository directory goes away suddenly, git-annex can create
a new empty directory in its place and start putting files in there.

* I've seen this happen when a removable drive that's a remote is unmounted
  and git-annex is running and stores a file on the remote. Since
  git-annex's cwd is not on the remote and it may not have any files open
  when it's unmounted, the unmount proceeds. When the mount point is
  /media/username/drive, the automounter may delete the mount point, and
  git-annex then recreates it and may write files to it, which is the wrong
  location. This can also cause problems with later mounting of the drive;
  some automounters fail if the mount point pre-exists.

* A move of a directory to another path can also lead to git-annex writing
  to the old path and re-creating the directory. While it mostly uses
  relative paths to cwd, and so is fine, there may be cases where it needs
  to use an absolute path.

* Odd behavior has been reported if the repository is deleted while
  git-annex is running it it. Including a git-annex seeming to hang or
  spin. <https://github.com/datalad/datalad/issues/3613>
  
  The sooner git-annex gives up in
  such a situation, the less likely it is do get into an unusual state.

What's needed is an action that creates directories only up to a given
point, which can be either .git/annex or the top of the worktree depending
on what's being done. --[[Joey]]