For example:

$ EDITOR=true git cl description
Traceback (most recent call last):
  File "/s/depot_tools/git_cl.py", line 5347, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/s/depot_tools/git_cl.py", line 5329, in main
    return dispatcher.execute(OptionParser(), argv)
  File "/s/depot_tools/subcommand.py", line 252, in execute
    return command(parser, args[1:])
  File "/s/depot_tools/git_cl.py", line 4026, in CMDdescription
    cl.UpdateDescription(description.description, force=options.force)
  File "/s/depot_tools/git_cl.py", line 1475, in UpdateDescription
    self._codereview_impl.UpdateDescriptionRemote(description, force=force)
  File "/s/depot_tools/git_cl.py", line 2465, in UpdateDescriptionRemote
    description, notify='NONE')
  File "/s/depot_tools/gerrit_util.py", line 626, in SetCommitMessage
    raise e
gerrit_util.GerritError: Conflict: New commit message cannot be same as existing commit message

Expected behavior is that it should just exit 0 :)