What would appropriate caution be when using unsafeDelete?

[xaviershay]

Docs for unsafeDelete state:

This is not an atomic operation, however. Use with caution!

What would be an appropriate level of caution? External synchronization?

Is the risk that another operation would get a stale read, or could this potentially corrupt the data structure?

Thanks!

[mcschroeder]

External synchronization would definitely be appropriate.

The risk of unsafeDelete is merely loss of atomicity and isolation. Since it acts outside of STM, concurrent transactions might experience phantom reads and so on. But not data corruption—at least not on the level of the data structure itself; from the point of view of your application logic there might of course be trouble!

[xaviershay]

thank you, most helpful. FWIW I'm looking to use it in a game server: https://github.com/xaviershay/legendary-bench/blob/1fa7c40f444751855d228d38c8930fada87a6d4e/api/src/Api.hs#L51

(This is mostly academic - once I add real persistence it won't be an issue.)