Test that raising an exception in the release function doesn't cause the lock to choke

  $ cat > testlock.py << EOF

  > from mercurial import cmdutil, error, util

  > 

  > cmdtable = {}

  > command = cmdutil.command(cmdtable)

  > 

  > def acquiretestlock(repo, releaseexc):

  >     def unlock():

  >         if releaseexc:

  >             raise util.Abort('expected release exception')

  >     l = repo._lock(repo.vfs, 'testlock', False, unlock, None, 'test lock')

  >     return l

  > 

  > @command('testlockexc')

  > def testlockexc(ui, repo):

  >     testlock = acquiretestlock(repo, True)

  >     try:

  >         testlock.release()

  >     finally:

  >         try:

  >             testlock = acquiretestlock(repo, False)

  >         except error.LockHeld:

  >             raise util.Abort('lockfile on disk even after releasing!')

  >         testlock.release()

  > EOF

  $ cat >> $HGRCPATH << EOF

  > [extensions]

  > testlock=$TESTTMP/testlock.py

  > EOF

  $ hg -R b testlockexc

  abort: expected release exception

  [255]