etseidl commented on issue #7909: URL: https://github.com/apache/arrow-rs/issues/7909#issuecomment-3073814710
> What behavior would we want from a thrift parser? To avoid this problem, each generated enum would need to have some `UNKNOWN` / `UNSUPPORTED` variant. As I understand it, thrift is meant to be forward compatible, and `ColumnOrder` is definitely intended to be so. In C++, `union`s are modeled as a struct of structs along with a bitfield indicating which, if any, of the members are valid. If an unknown value is encountered, it simply returns an empty struct with all bit fields '0'. For `enum`, the rust thrift implementation was changed from a rust `enum` to a `struct` with a single `i32` for the discriminant, with constants defined for each known value. An unknown value `i` is returned as `EnumName(i)`, which removes the need for an `UNDEFINED` special value. We could take a similar approach for `union`. A struct with an "enum struct" discriminant, along with `Option<struct>` fields for each variant. An unknown `i` would then have `i` for the enum part and `None` for all members. Getters for the fields could test the discriminant and return `None` if it is incorrect for the field. > For `ColumnOrder` we could just ignore the statistics in that case, but I'm not sure whether in general this would just move the error to another place in the code. In the specific `ColumnOrder` case, its as-designed behavior is that when an unknown order is encountered, statistics for that column are to be ignored. This is not currently enforced in rust, but @adriangb and I attempted to address it in https://github.com/apache/datafusion/pull/15821. arrow-rs should likely also be changed to not populate statistics for columns with undefined orders. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
