tests/test-journal-exists.t

test-lfs: add tests demonstrating the interaction with largefiles

Obviously the original series needs to be accepted first, but there are concerns
about how well these extensions will play together before proceeding.  It looks
like the answer is surprisingly well.  There are some merge surprises
(largefiles seems to combine the choice of "keep tracking as a large/normal
file" with taking the content of the large/normal file) and some existing diff
weirdness (largefiles diffs the standins, not the large file).  Converting the
repo to normal files seemlessly transitions to lfs on the fly.  I didn't test
going the other way, because I'm not sure why anyone would want to do that.

I flagged the lack of a repo requirement after converting, because some of the
unsubmitted changes I have add a requirement on commit, but this somehow misses
the convert case.

I flagged an issue where devel-warnings are emitted on convert, which is a
separate issue.

  $ 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' to clean up transaction)
  [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:

#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
  abort: Permission denied: $TESTTMP/foo/.hg/store/.00changelog.i-* (glob)
  [255]

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