Hash equality with regular sets?

[martinklepsch]

Undecided if hashes of regular sets should match with hashes of cc-sets. Need to better understand consequences.

[jstepien]

On the JVM side of things, according to Oracle's docs:

If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.

The implementation indicates that a custom comparator set is Object.equals to a set with same contents:

  Object
  (equals [this that]
    (cond (identical? this that)     true
          (= (-> this seq set) that) true
          :else false))

In this light I suspect that their hashes should be equal.

[martinklepsch]

Thanks for the hint, sounds right 👍

That said the hashCode and hasheq + hash caching stuff isn't done properly yet I think. I don't fully understand all this stuff yet (also with regards to ClojureScript). If you want to contribute in that direction I'd be happy about your help 😃