sync error

Syncing work tree:  97% (286/294)  Traceback (most recent call last):
  File "/home/fun/android/.repo/repo/main.py", line 418, in <module>
    _Main(sys.argv[1:])
  File "/home/fun/android/.repo/repo/main.py", line 394, in _Main
    result = repo._Run(argv) or 0
  File "/home/fun/android/.repo/repo/main.py", line 142, in _Run
    result = cmd.Execute(copts, cargs)
  File "/home/fun/android/.repo/repo/subcmds/sync.py", line 657, in Execute
    project.Sync_LocalHalf(syncbuf)
  File "/home/fun/android/.repo/repo/project.py", line 1106, in Sync_LocalHalf
    lost = self._revlist(not_rev(revid), HEAD)
  File "/home/fun/android/.repo/repo/project.py", line 2074, in _revlist
    return self.work_git.rev_list(*a, **kw)
  File "/home/fun/android/.repo/repo/project.py", line 2227, in rev_list
    p.stderr))
error.GitError: platform/system/bluetooth rev-list ('^1fe9aac7bae444d50dbc338662a9b1d655608298', 'HEAD', '--'): fatal: Not a git repository (or any of the parent directories): .git