friendlymatthew commented on code in PR #7921: URL: https://github.com/apache/arrow-rs/pull/7921#discussion_r2203048613
########## parquet-variant-compute/src/shredding.rs: ########## @@ -0,0 +1,349 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use arrow_schema::{ArrowError, DataType, Fields}; + +// Keywords defined by the shredding spec +pub const METADATA: &str = "metadata"; +pub const VALUE: &str = "value"; +pub const TYPED_VALUE: &str = "typed_value"; + +pub fn validate_value_and_typed_value( + fields: &Fields, + allow_both_null: bool, +) -> Result<(), ArrowError> { + let value_field_res = fields.iter().find(|f| f.name() == VALUE); + let typed_value_field_res = fields.iter().find(|f| f.name() == TYPED_VALUE); + + if !allow_both_null { + if let (None, None) = (value_field_res, typed_value_field_res) { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: StructArray must contain either `value` or `typed_value` fields or both.".to_string() + )); + } + } + + if let Some(value_field) = value_field_res { + // if !value_field.is_nullable() { + // return Err(ArrowError::InvalidArgumentError( + // "Expected value field to be nullable".to_string(), + // )); + // } + + if value_field.data_type() != &DataType::BinaryView { + return Err(ArrowError::NotYetImplemented(format!( + "VariantArray 'value' field must be BinaryView, got {}", + value_field.data_type() + ))); + } + } + + if let Some(typed_value_field) = fields.iter().find(|f| f.name() == TYPED_VALUE) { + // if !typed_value_field.is_nullable() { + // return Err(ArrowError::InvalidArgumentError( + // "Expected value field to be nullable".to_string(), + // )); + // } + + // this is directly mapped from the spec's parquet physical types + // note, there are more data types we can support + // but for the sake of simplicity, I chose the smallest subset + match typed_value_field.data_type() { + DataType::Boolean + | DataType::Int32 + | DataType::Int64 + | DataType::Float32 + | DataType::Float64 + | DataType::BinaryView => {} + DataType::Union(union_fields, _) => { + union_fields + .iter() + .map(|(_, f)| f.clone()) + .try_for_each(|f| { + let DataType::Struct(fields) = f.data_type().clone() else { + return Err(ArrowError::InvalidArgumentError( + "Expected struct".to_string(), + )); + }; + + validate_value_and_typed_value(&fields, false) + })?; + } + + foreign => { + return Err(ArrowError::NotYetImplemented(format!( + "Unsupported VariantArray 'typed_value' field, got {foreign}" + ))) + } + } + } + + Ok(()) +} + +/// Validates that the provided [`Fields`] conform to the Variant shredding specification. +/// +/// # Requirements +/// - Must contain a "metadata" field of type BinaryView +/// - Must contain at least one of "value" (optional BinaryView) or "typed_value" (optional with valid Parquet type) +/// - Both "value" and "typed_value" can only be null simultaneously for shredded object fields +pub fn validate_shredded_schema(fields: &Fields) -> Result<(), ArrowError> { + let metadata_field = fields + .iter() + .find(|f| f.name() == METADATA) + .ok_or_else(|| { + ArrowError::InvalidArgumentError( + "Invalid VariantArray: StructArray must contain a 'metadata' field".to_string(), + ) + })?; + + if metadata_field.is_nullable() { + return Err(ArrowError::InvalidArgumentError( + "Invalid VariantArray: metadata field can not be nullable".to_string(), + )); + } + + if metadata_field.data_type() != &DataType::BinaryView { + return Err(ArrowError::NotYetImplemented(format!( + "VariantArray 'metadata' field must be BinaryView, got {}", + metadata_field.data_type() + ))); + } + + validate_value_and_typed_value(fields, false)?; + + Ok(()) +} + +#[cfg(test)] +mod tests { + use super::*; + + use arrow_schema::{Field, UnionFields, UnionMode}; + + #[test] + fn test_regular_variant_schema() { + // a regular variant schema + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let value_field = Field::new("value", DataType::BinaryView, false); + + let schema = Fields::from(vec![metadata_field, value_field]); + + validate_shredded_schema(&schema).unwrap(); + } + + #[test] + fn test_regular_variant_schema_order_agnostic() { + // a regular variant schema + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let value_field = Field::new("value", DataType::BinaryView, false); + + let schema = Fields::from(vec![value_field, metadata_field]); // note the order switch + + validate_shredded_schema(&schema).unwrap(); + } + + #[test] + fn test_regular_variant_schema_allow_other_columns() { + // a regular variant schema + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let value_field = Field::new("value", DataType::BinaryView, false); + + let trace_field = Field::new("trace_id", DataType::Utf8View, false); + let created_at_field = Field::new("created_at", DataType::Date64, false); + + let schema = Fields::from(vec![ + metadata_field, + trace_field, + created_at_field, + value_field, + ]); + + validate_shredded_schema(&schema).unwrap(); + } + + #[test] + fn test_regular_variant_schema_missing_metadata() { + let value_field = Field::new("value", DataType::BinaryView, false); + let schema = Fields::from(vec![value_field]); + + let err = validate_shredded_schema(&schema).unwrap_err(); + + assert_eq!( + err.to_string(), + "Invalid argument error: Invalid VariantArray: StructArray must contain a 'metadata' field" + ); + } + + #[test] + fn test_regular_variant_schema_nullable_metadata() { + let metadata_field = Field::new("metadata", DataType::BinaryView, true); + let value_field = Field::new("value", DataType::BinaryView, false); + + let schema = Fields::from(vec![metadata_field, value_field]); + + let err = validate_shredded_schema(&schema).unwrap_err(); + + assert_eq!( + err.to_string(), + "Invalid argument error: Invalid VariantArray: metadata field can not be nullable" + ); + } + + #[test] + fn test_regular_variant_schema_allow_nullable_value() { + // a regular variant schema + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let value_field = Field::new("value", DataType::BinaryView, true); + + let schema = Fields::from(vec![metadata_field, value_field]); + + validate_shredded_schema(&schema).unwrap(); + } + + #[test] + fn test_shredded_variant_schema() { + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let typed_value_field = Field::new("typed_value", DataType::Int64, false); + let schema = Fields::from(vec![metadata_field, typed_value_field]); + + validate_shredded_schema(&schema).unwrap(); + } + + #[test] + fn test_partially_shredded_variant_schema() { + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let value_field = Field::new("value", DataType::BinaryView, false); + let typed_value_field = Field::new("typed_value", DataType::Int64, false); + let schema = Fields::from(vec![metadata_field, value_field, typed_value_field]); + + validate_shredded_schema(&schema).unwrap(); + } + + #[test] + fn test_partially_shredded_variant_list_schema() { + /* + optional group tags (VARIANT) { + required binary metadata; + optional binary value; + optional group typed_value (LIST) { # must be optional to allow a null list + repeated group list { + required group element { # shredded element + optional binary value; + optional binary typed_value (STRING); + } + required group element { # shredded element + optional binary value; + optional int64 typed_value ; + } + } + } + } + */ + + let metadata_field = Field::new("metadata", DataType::BinaryView, false); + let value_field = Field::new("value", DataType::BinaryView, false); + + // Define union fields for different element types + let string_element = { + let value_field = Field::new("value", DataType::BinaryView, true); + let typed_value = Field::new("typed_value", DataType::BinaryView, true); + DataType::Struct(Fields::from(vec![value_field, typed_value])) + }; + + let int_element = { + let value_field = Field::new("value", DataType::BinaryView, true); + let typed_value = Field::new("typed_value", DataType::Int64, true); + DataType::Struct(Fields::from(vec![value_field, typed_value])) + }; + + // Create union of different element types + let union_fields = UnionFields::new( + vec![0, 1], + vec![ + Field::new("string_element", string_element, true), + Field::new("int_element", int_element, true), + ], + ); Review Comment: I don't love this, the field names are weird. However, we need a way to support a heterogenous list of `Fields`. I'm curious if there is a nicer way to represent a group. -- 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 For queries about this service, please contact Infrastructure at: us...@infra.apache.org
