$ fastobs="$TESTDIR"/../hgext/hgfastobs.py

  $ echo 'from mercurial import obsolete ; obsolete._enabled = True' > enableobs.py

  $ cat >> $HGRCPATH <<EOF

  > [obsolete]

  > syncstrategy = boxfill

  > [extensions]

  > EOF

  $ echo "enable-obsolete = $PWD/enableobs.py" >> $HGRCPATH

  $ echo "fastobs = $fastobs" >> $HGRCPATH

  $ hg init alice

  $ hg init bob

  $ hg init trent

  $ cd alice

  $ echo a > a

  $ hg addr && hg ci -m 'add a'

  adding a

  $ echo aa >> a

  $ hg ci -m 'edit a'

  $ echo aa > a

  $ hg ci --amend -m 'edit a'

  $ hg debugobsolete

  e772e827cd64564621e7e5af15c9f848e3b92c8e efa8cd969bc37e6a1330c29f4234fe9e9be681b3 0 {'date': '* 0', 'user': 'test'} (glob)

  5ccfcbc00f2a19cd7affedce5ff087e68e67c6cc 0 {'date': '* 0', 'user': 'test'} (glob)

  $ hg push ../trent

  pushing to ../trent

  searching for changes

  adding changesets

  adding manifests

  adding file changes

  added 2 changesets with 2 changes to 1 files

  boxpush: about to transmit 2 obsolete markers (2 markers total)

  $ cd ../bob

  $ hg pull ../trent

  pulling from ../trent

  requesting all changes

  adding changesets

  adding manifests

  adding file changes

  added 2 changesets with 2 changes to 1 files

  (run 'hg update' to get a working copy)

  $ hg debugobsolete | sort

  5ccfcbc00f2a19cd7affedce5ff087e68e67c6cc 0 {'date': '* 0', 'user': 'test'} (glob)

  e772e827cd64564621e7e5af15c9f848e3b92c8e efa8cd969bc37e6a1330c29f4234fe9e9be681b3 0 {'date': '* 0', 'user': 'test'} (glob)