Hash of enum from module gives inconsistent values run to run

[Sukera]

@sandsq

Specifically, the order they come out when I collect them is different run to run (this was the headache I was running into, since I was using shuffle! on the collection with a fixed rng seed but getting a different order each time).

Dicts in Julia don’t have an order; even without hash giving different values run to run, the order is not stable. You can use OrderedCollections if you need a collection with an order.

@sandsq

enums already get a Base.hash function for them?

There is a fallback definition, yes, which ultimately falls back to using objectid, which may give a different result due to the module the enum is in changing run to run.

Also, hashing Base.Enum values is a bit tricky, because under the hood they are primitive types.