$ hg init repo
  $ cd repo
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > sparse=$TESTDIR/../hgext/fbsparse.py
  > dragdag=$RUNTESTDIR/drawdag.py
  > rebase=
  > EOF

  $ hg debugdrawdag <<'EOS'
  >   D
  >   |
  > B C
  > |/
  > A
  > EOS

  $ hg sparse --exclude A B C D E
  $ hg update A -q
  $ printf D > D
  $ echo 2 > E
  $ hg rebase -s C -d B
  rebasing 2:dc0947a82db8 "C" (C)
  temporarily included 1 file(s) in the sparse checkout for merging
  cleaned up 1 temporarily added file(s) from the sparse checkout
  rebasing 3:e7b3f00ed42e "D" (D tip)
  temporarily included 1 file(s) in the sparse checkout for merging
  cleaned up 1 temporarily added file(s) from the sparse checkout
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/dc0947a82db8-b8481714-rebase.hg (glob)