keyword: mimic cmdutil.bail_if_changed even more At the check before overwriting with kwexpand, kwshrink: - abort when in middle of merge - give terser abort message

keyword: use dirstate.parents to obtain current first parent This should be quicker than changectx().node()

keyword: monkeypatch dispatch._runcommand instead of _parse We want the current command, and hooking into this method makes it more transparent what we are doing.