Adding empty directory gives bogus error message

Hello,

During a talk with madduck on #git today, we stumbled upon this
confusing error message:

  $ mkdir repo
  $ cd repo/
  $ git init
  Initialized empty Git repository in .git/
  $ mkdir empty
  $ git add empty/
  The following paths are ignored by one of your .gitignore files:
  empty/ (directory)
  Use -f if you really want to add them.
  $ git add -f empty/
  fatal: unable to index file empty/

First, it misleads the user by assuming that something was added to
.gitignore or another exclude file, and the second error message is not
very helpful.

Looking at the code, I am not sure how this can be fixed. Simply
printing a warning when finding "some" empty directory might do, but it
is not the best way to help somebody new to git. Refusing to add
anything when finding an empty directory deep in some hierarchy is not a
good option either.

Git 1.4 silently did nothing, so 1.5 at least tries to be more clueful.
Anyway, I thought I would mention it and see what happens. ;)

-- 
Jonas Fonseca