nl_tokens: Fetches the given branch s tree from its SHA and __resets any WorkingState for it__
pl_tokens: function fetchTree ( repoState , driver , branch ) { // Fetch a working tree for this branch return WorkingUtils . fetch ( driver , branch ) . <mask> ( ( newWorkingState ) => { return updateWorkingState ( repoState , branch , newWorkingState ) ; } ) ; }