[heleninboodler]

> The way you describe go's behavior is "takes snapshot of the underlying data", which usually means "deep copy container"

No, there is no mention of a "snapshot". You get a reference to the current backing array, which may or may not continue being used by the slice (depending on reallocations). You're pointing to the live slice backing array, and the values in it may change if someone else is manipulating the slice, up to the point where the slice backing array must be reallocated, at which point you'll continue pointing to the old backing array and be keeping it from getting GC'd.

[db48x]

And that’s really the problem with it. If you want to ensure that you have exclusive access to the element(s), then you have to explicitly copy them first or you get silent data corruption.

And if you want to ensure that multiple things have access to the elements, then you have to avoid reallocations or you get silent data loss.

No matter what you’re doing, a pointer to an element of an array or slice is usually the wrong thing in Go. The language would be better off without them.