"An inconsistent delta was supplied" error on commit after join to empty repo

If you try to do `bzr join' into a repository that has been initialized
with `bzr init' but never committed to, then `bzr commit' the result,
an error like the following occurs on the commit attempt:

    bzr: ERROR: An inconsistent delta was supplied involving 'p1f1', 'f1-20101224155901-x5ocv25cpaqsgla5-1'
    reason: working tree does not contain new entry

In that example, p1 is the subtree being joined, and f1 is a file
within it.

After the failed commit, `bzr log' shows version numbers that descend
below 0.

The attached script refers to this bug as the join-without-prior-commit bug.
There is no problem if there is at least one commit before the join.

Tested in Bzr 2.2.0 on Windows and MacOS and 2.1.2 under Cygwin.

Motivation for join without prior commit: Joining subprojects into a
master project after the subprojects are already underway.