DrChainsaw commented on issue #449: URL: https://github.com/apache/arrow-julia/issues/449#issuecomment-1577140314
After searching through the arrow repo after `arrow:extension` is seems like you might be right. [Here](https://github.com/apache/arrow/blob/f5a57292e5187b1a1640b04303e9f6b63135892a/cpp/src/arrow/extension_type.cc#L178) it is defined as a const in the cpp code for example and I could not find any trace of it being manipulated or changed anywhere (which would be a quite strange thing to do as well). The [c code](https://github.com/apache/arrow/blob/f5a57292e5187b1a1640b04303e9f6b63135892a/cpp/src/arrow/c/bridge.cc#L483) seems to accept the metadata as a vector of pairs through, so it would in theory allow for multiple identical keys, but python, java and Julia use dicts so there is no way to have it through any of them. It is a bit unclear to me what the ExtensionType stuff does in arrow and what one gets for buying in to it. However, most things points to it being a mechanism for your `foo` example. I close the issue now since my initial understanding of the extension metadata was incorrect and I don't think there is any action needed here. Just reopen or open another issue if there is a point about late conversion stuff (e.g. String <-> Symbol) not fitting into the definition of extensions. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
