GetAll：键和实体保证顺序相同吗？

Question

I've been using this to load entities and still have the keys available:

type Post struct {
    Title    string
    Created  time.Time
    // ...
    key      *datastore.Key
}

func All(c appengine.Context) (*[]Post, error) {
    var p []Post
    q := datastore.NewQuery("Post").Order("-Created")
    k, err := q.GetAll(c, &p)
    if err != nil {
        return nil, err
    }
    for i := 0; i < len(p); i++ {
        p[i].key = k[i]
    }
    return &p, nil
}

Then it occurred to me to wonder if I could always trust that k would be in the same order as p (that is, k[0] is always the key for p[0])? If I understand it correctly the appengine-go source suggests that it would, since both slices are build using append. It certainly seems to work.

Is what I'm doing safe? Is there a better way?

Answer 1

Yes, the keys returned by GetAll will be in the same order as the values appended to dst.