$ cat << EOF > buggylocking.py

  > """A small extension that acquire locks in the wrong order

  > """

  > 

  > from mercurial import cmdutil

  > 

  > cmdtable = {}

  > command = cmdutil.command(cmdtable)

  > 

  > @command('buggylocking', [], '')

  > def buggylocking(ui, repo):

  >     lo = repo.lock()

  >     wl = repo.wlock()

  > EOF

  $ cat << EOF >> $HGRCPATH

  > [extensions]

  > buggylocking=$TESTTMP/buggylocking.py

  > [devel]

  > all=1

  > EOF

  $ hg init lock-checker

  $ cd lock-checker

  $ hg buggylocking

  "lock" taken before "wlock"

  $ cat << EOF >> $HGRCPATH

  > [devel]

  > all=0

  > check-locks=1

  > EOF

  $ hg buggylocking

  "lock" taken before "wlock"

  $ hg buggylocking --traceback

  "lock" taken before "wlock"

   at:

   */hg:* in <module> (glob)

   */mercurial/dispatch.py:* in run (glob)

   */mercurial/dispatch.py:* in dispatch (glob)

   */mercurial/dispatch.py:* in _runcatch (glob)

   */mercurial/dispatch.py:* in _dispatch (glob)

   */mercurial/dispatch.py:* in runcommand (glob)

   */mercurial/dispatch.py:* in _runcommand (glob)

   */mercurial/dispatch.py:* in checkargs (glob)

   */mercurial/dispatch.py:* in <lambda> (glob)

   */mercurial/util.py:* in check (glob)

   $TESTTMP/buggylocking.py:* in buggylocking (glob)

  $ cd ..