1 Just exercize debugindexdot

     2 Create a short file history including a merge.

     3   $ hg init t

     4   $ cd t

     5   $ echo a > a

     6   $ hg ci -qAm t1 -d '0 0'

     7   $ echo a >> a

     8   $ hg ci -m t2 -d '1 0'

     9   $ hg up -qC 0

    10   $ echo b >> a

    11   $ hg ci -m t3 -d '2 0'

    12   created new head

    13   $ HGMERGE=true hg merge -q

    14   $ hg ci -m merge -d '3 0'

    15 

    16   $ hg debugindexdot .hg/store/data/a.i

    17   digraph G {

    18   	-1 -> 0

    19   	0 -> 1

    20   	0 -> 2

    21   	2 -> 3

    22   	1 -> 3

    23   }