tests/test-journal-exists.t

branchcache: do not accept "empty update"

This currently does not happens and it will be simpler that is remains that way.
If all update do something, we will be able to simply declare, in a later
changesets, that all update to result in a dirty branchcache.

  $ hg init repo
  $ cd repo
  $ 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' to clean up transaction)
  [255]

  $ hg recover
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)

recover, explicit verify

  $ touch .hg/store/journal
  $ hg ci -Am0
  abort: abandoned transaction found
  (run 'hg recover' to clean up transaction)
  [255]
  $ hg recover --verify  -q

recover, no verify

  $ touch .hg/store/journal
  $ hg ci -Am0
  abort: abandoned transaction found
  (run 'hg recover' to clean up transaction)
  [255]
  $ hg recover --no-verify
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)


Check that zero-size journals are correctly aborted:

#if unix-permissions no-root
  $ hg bundle -qa repo.hg
  $ chmod -w foo/.hg/store/00changelog.i

  $ hg -R foo unbundle repo.hg
  adding changesets
  transaction abort!
  rollback completed
  abort: $EACCES$: '$TESTTMP/repo/foo/.hg/store/.00changelog.i-*' (glob)
  [255]

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