thswlsqls opened a new issue, #8677: URL: https://github.com/apache/paimon/issues/8677
**Search before asking** - [x] I searched in the [issues](https://github.com/apache/paimon/issues) and found nothing similar. **Paimon version** master @ f7ec93b3c (2.0-SNAPSHOT) **Compute Engine** Engine-agnostic (core) — surfaces via any writer using the Lance file format. **Minimal reproduce step** Create a table with the `lance` file format containing a MULTISET column, e.g. `RowType.of(DataTypes.MULTISET(DataTypes.STRING()))`, then write to it. `LanceFileFormat.LanceRowTypeVisitor.visit(MultisetType)` (paimon-lance/src/main/java/org/apache/paimon/format/lance/LanceFileFormat.java) returns `null`, so schema validation passes. But the Lance write path goes through Arrow: `ArrowFieldTypeConversion.ArrowFieldTypeVisitor.visit(MultisetType)` throws `UnsupportedOperationException("Doesn't support MultisetType.")`. **What doesn't meet your expectations?** A MULTISET column passes `validateDataFields()` at schema-creation time but fails opaquely at first write. The sibling `visit(MapType)` in the same visitor already rejects MAP at validation time with a clear message. MULTISET should be rejected the same way. **Anything else?** N/A **Are you willing to submit a PR?** - [x] I'm willing to submit a PR! -- 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]
