Hey everyone, The REST spec <https://github.com/apache/iceberg/blob/6319712b612b724fedbc5bed41942ac3426ffe48/open-api/rest-catalog-open-api.yaml#L225> currently uses *%1F* as the UTF-8 encoded namespace separator for multi-part namespaces. This causes issues <https://github.com/apache/iceberg/issues/10338>, since it's a control character <https://www.compart.com/en/unicode/category/Cc> and the Servlet spec <https://jakarta.ee/specifications/servlet/6.0/jakarta-servlet-spec-6.0.html#uri-path-canonicalization> can reject such characters.
I'm proposing to replace *%1F* with a different character that isn't problematic (such as *%2E*) and also add some backwards compatible namespace decoding logic to *RESTUtil* so that older clients sending *%1F* can still do so. PS: I also investigated why *%1F* doesn't fail in *TestRESTCatalog* and it's because we're using Jetty 9.x and the javax.servlet API 4.0 (instead of 6.x). I'll open a separate PR to upgrade Jetty and use jakarta.servlet API 6.x, which will reproduce the issue with *%1F* being used as the namespace separator. Eduard
