With the following darcs version, darcs2 format repos are confused by
spaces in filenames.

$ darcs --version
2.0.0pre3 (unknown)
$ darcs --exact-version
darcs compiled on Feb  2 2008, at 06:31:14
unknown
$

The following transcript demonstrates the issue.

$ darcs init --darcs-2
$ touch 'x y'
$ darcs rec -lam 'x y' 'x y'
Recording changes in "x y":

Finished recording patch 'x y'
$ echo >'x y'
$ echo yd | darcs ame -a 'x y'
Amending changes in "x y":

Thu Mar 27 12:32:32 EST 2008  Trent W. Buck <trentbuck@gmail.com>
  * x y
Shall I amend this patch? [yNvpxq], or ? for help:

darcs failed:  File ./x does not exist.