[BUG] Export, or add, or something is b0rked

[Bryan O'Sullivan]

Using version bf9d55ed67f6+20050701 (i.e. the tip of Matt's published
tree), I run into the following problem when I add a file:

~/hg/hg-rpm $ hg add contrib/buildrpm
~/hg/hg-rpm $ hg commit -t "Add script to build RPM packages in place"
~/hg/hg-rpm $ hg export tip
# HG changeset patch
# User Bryan O'Sullivan <bos at serpentine.com>
# Node ID d875295879a48c7e07a4010dac1d13e6bc23196c
# Parent  b580900ca10c83f421c9b38cb991596a66c0002b

Add script to build RPM packages in place

Traceback (most recent call last):
  File "/home/bos/bin/hg", line 13, in ?
    commands.run()
  File "/home/bos/lib64/python/mercurial/commands.py", line 842, in run
    sys.exit(dispatch(sys.argv[1:]))
  File "/home/bos/lib64/python/mercurial/commands.py", line 908, in dispatch
    return d()
  File "/home/bos/lib64/python/mercurial/commands.py", line 893, in <lambda>
    d = lambda: i[0](u, repo, *args, **cmdoptions)
  File "/home/bos/lib64/python/mercurial/commands.py", line 440, in export
    dodiff(ui, repo, None, prev, node)
  File "/home/bos/lib64/python/mercurial/commands.py", line 79, in dodiff
    to = repo.file(f).read(mmap[f])
KeyError: 'contrib/buildrpm'