Frank Terbeck wrote on Mon, Jun 02, 2014 at 10:14:22 +0200:
> Hello Daniel,
> 
> Daniel Shahaf wrote:
> > vcs_info git false-negatives to detect staged changes in a repository that has
> > no commits.  Attached a patch for that.
> 
> Great!
> 
> > The patch includes two variants for computing the "has staged changes?" bit in
> > empty repositories: one via 'git ls-files' and one via git's empty tree.
> >
> > - The output of ls-files isn't O(1), but I tested with a 3000-file tree and
> >   didn't notice a slowdown, so I suppose it's acceptable.
> >
> > - 'diff-index --cached --quiet $empty_tree' is an O(1) operation, but I am not
> >   sure whether it is forwards compatible with future versions of Git, i.e.,
> >   whether it's a hack that happens to work or a legitimate use of git's API.
> >
> > WDYT?
> 
> I'm with Aaron on this one. IIRC, git uses the diff-index command in
> various places, so I don't think it'll be removed anytime soon.

My concern was not with using diff-index but with using the empty tree.
Since Aaron says using it would be robust, let's just use it.  Attached.

> If you don't want the second variant to be forgotten, you can always put
> it into the change's commit message. But in the code I'd just use the
> variant that you think is faster (if only theoretically).

It's mentioned in this thread, good enough for me.

Daniel