$ hg init

  $ echo a > a

  $ hg ci -Am0

  adding a

  $ hg -q clone . foo

  $ touch .hg/store/journal

  $ echo foo > a

  $ hg ci -Am0

  abort: abandoned transaction found - run hg recover!

  [255]

  $ hg recover

  rolling back interrupted transaction

  checking changesets

  checking manifests

  crosschecking files in changesets and manifests

  checking files

  1 files, 1 changesets, 1 total revisions

Check that zero-size journals are correctly aborted:

  $ hg bundle -qa repo.hg

  $ chmod -w foo/.hg/store/00changelog.i

  $ hg -R foo unbundle repo.hg

  adding changesets

  abort: Permission denied: .*

  [255]

  $ if test -f foo/.hg/store/journal; then echo 'journal exists :-('; fi