$ cat >> $HGRCPATH <<EOF

  > [web]

  > push_ssl = false

  > allow_push = *

  > [phases]

  > publish=False

  > [alias]

  > odiff=diff --rev 'limit(obsparents(.),1)' --rev .

  > [extensions]

  > hgext.graphlog=

  > EOF

  $ mkcommit() {

  >    echo "$1" > "$1"

  >    hg add "$1"

  >    hg ci -m "add $1"

  > }

create commit

  $ hg init repo

  $ cd repo

  $ mkcommit a

  $ mkcommit b

  $ hg up -q 0

  $ mkcommit c

  created new head

forge old style relation files

  $ hg log -r 2 --template='{node} ' > .hg/obsolete-relations

  $ hg log -r 1 --template='{node}' >> .hg/obsolete-relations

enable the extensions

  $ echo "obsolete=$(echo $(dirname $TESTDIR))/hgext/obsolete.py" >> $HGRCPATH

  $ hg glog

  abort: old format of obsolete marker detected!

  run `hg debugconvertobsolete` once.

  [255]

  $ hg debugconvertobsolete --traceback

  1 obsolete marker converted

  $ hg glog

  @  changeset:   2:d67cd0334eee

  |  tag:         tip

  |  parent:      0:1f0dee641bb7

  |  user:        test

  |  date:        Thu Jan 01 00:00:00 1970 +0000

  |  summary:     add c

  |

  o  changeset:   0:1f0dee641bb7

     user:        test

     date:        Thu Jan 01 00:00:00 1970 +0000

     summary:     add a

  $ hg debugconvertobsolete

  nothing to do

  0 obsolete marker converted