$ with-temp-dir
with-temp-dir: entering directory `/tmp/tmp.xZnXy20807'
This directory will be deleted when you exit.
$ twb-get yi
darcs get --partial --set-scripts-executable http://www.cse.unsw.edu.au/~dons/yi yi
Copying patch 655 of 655... done!
Applying patch 654 of 654... done.
Finished getting.
$ darcs optimize --checkpoint --repodir=yi
Checkpointing tag:
Mon Mar 28 13:38:22 EST 2005  Don Stewart <dons@cse.unsw.edu.au>
  tagged yi-0.1.0
darcs: bug in darcs!
fromJust error at DarcsRepo.lhs:526 compiled 11:31:02 May 19 2007
Please report this to bugs@darcs.net,
If possible include the output of 'darcs --exact-version'.
$ darcs --exact-version
darcs compiled on May 19 2007, at 11:33:36
# configured Mon Oct  9 15:12:44 EDT 2006
./configure --no-create --no-recursion

Context:

[TAG 1.0.9rc1
Tommy Pettersson <ptp@lysator.liu.se>**20061008175207]
$
with-temp-dir: leaving directory `/tmp/tmp.xZnXy20807'
$
-- 
Trent Buck

Note the --partial.

I just submitted a regression test update to "partial.sh" which demonstrates
that this bug is "resolved in unstable" using Darcs 2 and a darcs-2 format
repository.