Re: [PATCH/POC 3/7] setup.c: add split-repo support to .git files

On Sat, Dec 14, 2013 at 3:43 AM, Jonathan Nieder [off-list ref] wrote:

Problems:

 * What if I move my worktree with "mv"?  Then I still need the
   corresponding $GIT_SUPER_DIR/repos/<id> directory, and nobody told
   the GIT_SUPER_DIR about it.

 * What if my worktree is on removable media (think "network
   filesystem") and has just been temporarily unmounted instead of
   deleted?

So maybe it would be nicer to:

  i. When the worktree is on the same filesystem, keep a *hard link* to
     some file in the worktree (e.g., the .git file).  If the link count
     goes down, it is safe to remove the $GIT_SUPER_DIR/repos/<id>
     directory.

Link count goes down to 1 if I move the worktree to a different
filesystem and it's not safe to remove $GIT_SUPER_DIR/repos/<id> in
this case, I think.

 ii. When the worktree is on another filesystem, always keep
     $GIT_SUPER_DIR/repos/<id> unless the user decides to manually
     remove it.  Provide documentation or a command to list basic
     information about $GIT_SUPER_DIR/repos directories (path to
     worktree, what branch they're on, etc).

(i) doesn't require any futureproofing.  As soon as someone wants it,
they can implement the check and fall back to (ii) for worktrees
without the magic hard link.

(ii) would benefit from recording the working tree directory as a
possibly unreliable, human-friendly reminder.

-- 
Duy