Some code that's not working right

aoc2019-18-1.go

// this is the node thing for getting from the start position to the last key
type path struct {
  name     string
  node     *tile
  steps    int
  parent   *path
  children []path

  keysFound []string

  final bool

  mapNow grid
}

// traverse takes a root node ( the '@' node ) and creates a graph
// the graph won't be even or whatever the term is for each branch being the
// same length because it'll stop adding nodes whenever there are no 'gettable'
// keys left from where it ends up
func traverse(in path) path {
  if in.final {
    return in
  }

  tmpGrid := in.mapNow.getCopy() /// make a copy
  keys := tmpGrid.getableKeys(in.node)
  
  // for all those keys
  for _, k := range keys {
    ng := tmpGrid.getCopy() /// do it again to be safe -- apparently messing up
    // because when we do a second loop for [e d] it's not getting the right map
    d := ng.tileToTileSteps(in.node, k)

    kn := k.key
    kf := []string{kn}
    if len(in.keysFound) > 0 {
      kf = append(kf, in.keysFound...)
    }

    ng2 := ng.removeKey(kn) // another copy
    keysLeft := ng2.keys()
    gettableKeys := ng2.getableKeys(k)
    
    k.key = ""

    np := path{
      name:      kn,
      node:      k,
      parent:    &in,
      steps:     in.steps + d,
      children:  []path{},
      mapNow:    ng2.getCopy(), // do it again again, to be super safe?
      final:     len(keysLeft) <= 0,
      keysFound: kf,
    }

    if len(keysLeft) > 0 && len(gettableKeys) > 0 {
      np = traverse(np)
    }

    in.children = append(in.children, np)
  }

  return in
}

// should be creating a copy of the map/grid/whatever, but maybe isn't???
func (g grid) getCopy() grid {
  out := make(grid)
  for n, t := range g {
    nei := map[string]edge{}
    for nn, e := range t.neighbours {
      nei[nn] = e
    }

    nt := &tile{
      id:         t.id,
      key:        t.key,
      door:       t.door,
      coord:      t.coord,
      neighbours: nei,
    }

    out[n] = nt
  }
  return out
}