Hi, Recently, I revisited the code for array equality in Rust. While going through it, I observed some assumptions about how we conclude that two elements of an arrow array are equal, and when two arrays are equal.
The notion of equality is also used throughout the document e.g. when we offer examples using "unspecified", we are implicitly arguing that we should not care about that value when comparing arrays. It is also used when we use the wording "unique values" in the dictionary-encoded arrays. The notion of array equality is important when we want to verify interoperability between languages, where we often need to compare arrays (e.g. after a round-trip), as some implementations may change the data of the "unspecified" slots and e.g. offsets. More fundamentally, IMO the specification offers a physical representation (buffers, childs, offests, etc) of a logical asset (lists, structs, int8, int32), but currently does not say when two logical assets are considered equal. Would it make sense to systematize the notion of equality in the specification, to align the different implementations into when they should consider two arrays to be equal? Best, Jorge
