alamb opened a new issue, #8296: URL: https://github.com/apache/arrow-rs/issues/8296
**Describe the bug** As part of testing integration with the parquet crate in https://github.com/apache/arrow-rs/pull/8133 I found that trying to write a VariantArray directly to `parquet` panics **To Reproduce** ``` // Use the VariantArrayBuilder to build a VariantArray let mut builder = VariantArrayBuilder::new(3); // row 1: {"name": "Alice"} let mut variant_builder = builder.variant_builder(); variant_builder.new_object().with_field("name", "Alice").finish()?; variant_builder.finish(); let array = builder.build(); // TODO support writing VariantArray directly // at the moment it panics when trying to downcast to a struct array let array: ArrayRef = Arc::new(array); // create a RecordBatch with the VariantArray let batch = RecordBatch::try_from_iter(vec![("data", array)])?; // write the RecordBatch to a Parquet file let file = std::fs::File::create("variant.parquet")?; let mut writer = ArrowWriter::try_new(file, batch.schema(), None)?; writer.write(&batch)?; writer.close()?; ``` This results in this panic ``` struct array thread 'main' panicked at arrow-array/src/cast.rs:904:30: struct array stack backtrace: 0: __rustc::rust_begin_unwind at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/std/src/panicking.rs:697:5 1: core::panicking::panic_fmt at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/core/src/panicking.rs:75:14 2: core::panicking::panic_display at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/core/src/panicking.rs:268:5 3: core::option::expect_failed at /rustc/29483883eed69d5fb4db01964cdf2af4d86e9cb2/library/core/src/option.rs:2081:5 4: core::option::Option<T>::expect at /Users/andrewlamb/.rustup/toolchains/1.89-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/option.rs:960:21 5: arrow_array::cast::AsArray::as_struct at /Users/andrewlamb/Software/arrow-rs/arrow-array/src/cast.rs:904:30 6: parquet::arrow::arrow_writer::levels::LevelInfoBuilder::try_new at ./src/arrow/arrow_writer/levels.rs:162:35 7: parquet::arrow::arrow_writer::levels::calculate_array_levels at ./src/arrow/arrow_writer/levels.rs:55:23 8: parquet::arrow::arrow_writer::compute_leaves at ./src/arrow/arrow_writer/mod.rs:625:18 9: parquet::arrow::arrow_writer::ArrowRowGroupWriter::write at ./src/arrow/arrow_writer/mod.rs:839:25 10: parquet::arrow::arrow_writer::ArrowWriter<W>::write ``` **Expected behavior** We should be able to write a VariantArray directly without such an error **Additional context** <!-- Add any other context about the problem here. --> -- 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.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
