bkietz opened a new issue, #44491: URL: https://github.com/apache/arrow/issues/44491
### Describe the enhancement requested In many situations, it'd be beneficial to have an error Status which was copyable without using the heap. For example, this is a frequent pain point with Result<T>. We want Result to be default constructible even if T isn't, so [a defaulted Result is an error](https://github.com/apache/arrow/blob/7a3c66ac8063bc2b2fe184cc02b1750565421f01/cpp/src/arrow/result.h#L114) but this requires heap allocating a Status::State which we immediately overwrite. Similarly, if the value or error is moved out of a Result we'd like to avoid managing the stored object and [wind up heap allocating a flag](https://github.com/apache/arrow/pull/44477). Allowing some Status objects to have static lifetime (for example, by tagging the `state_` pointer or adding `bool Status::State::is_static`) should not have an effect on the critical hot paths of [moving a status](https://github.com/apache/arrow/blob/7a3c66ac8063bc2b2fe184cc02b1750565421f01/cpp/src/arrow/status.h#L402) or [skipping deletion of ok status](https://github.com/apache/arrow/blob/7a3c66ac8063bc2b2fe184cc02b1750565421f01/cpp/src/arrow/status.h#L140). Copying will get slightly slower since we need to branch on `state_->is_static`, but that's already quite slow due to heap interaction. ### Component(s) C++ -- 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: issues-unsubscr...@arrow.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
