$ . "$TESTDIR/bzr-definitions"

  $ cat > treeset.py <<EOF

  > import sys

  > from bzrlib import workingtree

  > wt = workingtree.WorkingTree.open('.')

  > 

  > message, rootid = sys.argv[1:]

  > wt.set_root_id('tree_root-%s' % rootid)

  > wt.commit(message)

  > EOF

change the id of the tree root

  $ mkdir test-change-treeroot-id

  $ cd test-change-treeroot-id

  $ bzr init -q source

  $ cd source

  $ echo content > file

  $ bzr add -q file

  $ bzr commit -q -m 'Initial add'

  $ python ../../treeset.py 'Changed root' new

  $ cd ..

  $ hg convert source source-hg

  initializing destination source-hg repository

  scanning source...

  sorting...

  converting...

  1 Initial add

  0 Changed root

  $ manifest source-hg tip

  % manifest of tip

  644   file

  $ cd ..