vbarua commented on code in PR #20953: URL: https://github.com/apache/datafusion/pull/20953#discussion_r2940599696
########## datafusion/substrait/src/logical_plan/consumer/expr/nested.rs: ########## @@ -0,0 +1,139 @@ +// 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 crate::logical_plan::consumer::SubstraitConsumer; +use datafusion::common::{DFSchema, not_impl_err, substrait_err}; +use datafusion::execution::FunctionRegistry; +use datafusion::logical_expr::Expr; +use substrait::proto::expression::Nested; +use substrait::proto::expression::nested::NestedType; + +/// Converts a Substrait [Nested] expression into a DataFusion [Expr]. +/// +/// Substrait Nested expressions represent complex type constructors (list, struct, map) +/// where elements are full expressions rather than just literals. This is used by +/// producers that emit `Nested { list: ... }` for array construction, as opposed to +/// `Literal { list: ... }` which only supports scalar values. +pub async fn from_nested( + consumer: &impl SubstraitConsumer, + nested: &Nested, + input_schema: &DFSchema, +) -> datafusion::common::Result<Expr> { + let Some(nested_type) = &nested.nested_type else { + return substrait_err!("Nested expression requires a nested_type"); + }; + + match nested_type { + NestedType::List(list) => { + let mut args = Vec::with_capacity(list.values.len()); + for value in &list.values { + args.push(consumer.consume_expression(value, input_schema).await?); + } + + let make_array_udf = consumer.get_function_registry().udf("make_array")?; + Ok(Expr::ScalarFunction( + datafusion::logical_expr::expr::ScalarFunction::new_udf( + make_array_udf, + args, + ), + )) + } + NestedType::Struct(_) => { + not_impl_err!("Nested struct expressions are not yet supported") + } + NestedType::Map(_) => { + not_impl_err!("Nested map expressions are not yet supported") + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::logical_plan::consumer::utils::tests::test_consumer; + use substrait::proto::expression::Literal; + use substrait::proto::expression::nested::List; + use substrait::proto::{self, Expression}; + + fn make_i64_literal(value: i64) -> Expression { + Expression { + rex_type: Some(proto::expression::RexType::Literal(Literal { + nullable: false, + type_variation_reference: 0, + literal_type: Some(proto::expression::literal::LiteralType::I64(value)), + })), + } + } + + #[tokio::test] + async fn nested_list_with_literals() -> datafusion::common::Result<()> { + let consumer = test_consumer(); + let schema = DFSchema::empty(); + let nested = Nested { + nullable: false, + type_variation_reference: 0, + nested_type: Some(NestedType::List(List { + values: vec![ + make_i64_literal(1), + make_i64_literal(2), + make_i64_literal(3), + ], + })), + }; + + let expr = from_nested(&consumer, &nested, &schema).await?; + assert_eq!( + format!("{expr}"), + "make_array(Int64(1), Int64(2), Int64(3))" + ); + + Ok(()) + } + + #[tokio::test] + async fn nested_list_empty() -> datafusion::common::Result<()> { + let consumer = test_consumer(); + let schema = DFSchema::empty(); + let nested = Nested { + nullable: true, + type_variation_reference: 0, + nested_type: Some(NestedType::List(List { values: vec![] })), + }; + + let expr = from_nested(&consumer, &nested, &schema).await?; + assert_eq!(format!("{expr}"), "make_array()"); + + Ok(()) + } + + #[tokio::test] + async fn nested_list_missing_type() -> datafusion::common::Result<()> { Review Comment: minor: Your naming in this test made me think it was about the _list_ missing a type, when actually it's about the `Nested` message not having `nested_type` set. ```suggestion async fn nested_missing_type() -> datafusion::common::Result<()> { ``` ########## datafusion/substrait/src/logical_plan/consumer/expr/nested.rs: ########## @@ -0,0 +1,139 @@ +// 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 crate::logical_plan::consumer::SubstraitConsumer; +use datafusion::common::{DFSchema, not_impl_err, substrait_err}; +use datafusion::execution::FunctionRegistry; +use datafusion::logical_expr::Expr; +use substrait::proto::expression::Nested; +use substrait::proto::expression::nested::NestedType; + +/// Converts a Substrait [Nested] expression into a DataFusion [Expr]. +/// +/// Substrait Nested expressions represent complex type constructors (list, struct, map) +/// where elements are full expressions rather than just literals. This is used by +/// producers that emit `Nested { list: ... }` for array construction, as opposed to +/// `Literal { list: ... }` which only supports scalar values. +pub async fn from_nested( + consumer: &impl SubstraitConsumer, + nested: &Nested, + input_schema: &DFSchema, +) -> datafusion::common::Result<Expr> { + let Some(nested_type) = &nested.nested_type else { + return substrait_err!("Nested expression requires a nested_type"); + }; + + match nested_type { + NestedType::List(list) => { + let mut args = Vec::with_capacity(list.values.len()); + for value in &list.values { + args.push(consumer.consume_expression(value, input_schema).await?); + } + + let make_array_udf = consumer.get_function_registry().udf("make_array")?; + Ok(Expr::ScalarFunction( + datafusion::logical_expr::expr::ScalarFunction::new_udf( + make_array_udf, + args, + ), + )) + } + NestedType::Struct(_) => { + not_impl_err!("Nested struct expressions are not yet supported") + } + NestedType::Map(_) => { + not_impl_err!("Nested map expressions are not yet supported") + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::logical_plan::consumer::utils::tests::test_consumer; + use substrait::proto::expression::Literal; + use substrait::proto::expression::nested::List; + use substrait::proto::{self, Expression}; + + fn make_i64_literal(value: i64) -> Expression { + Expression { + rex_type: Some(proto::expression::RexType::Literal(Literal { + nullable: false, + type_variation_reference: 0, + literal_type: Some(proto::expression::literal::LiteralType::I64(value)), + })), + } + } + + #[tokio::test] + async fn nested_list_with_literals() -> datafusion::common::Result<()> { + let consumer = test_consumer(); + let schema = DFSchema::empty(); + let nested = Nested { + nullable: false, + type_variation_reference: 0, + nested_type: Some(NestedType::List(List { + values: vec![ + make_i64_literal(1), + make_i64_literal(2), + make_i64_literal(3), + ], + })), + }; + + let expr = from_nested(&consumer, &nested, &schema).await?; + assert_eq!( + format!("{expr}"), + "make_array(Int64(1), Int64(2), Int64(3))" + ); + + Ok(()) + } + + #[tokio::test] + async fn nested_list_empty() -> datafusion::common::Result<()> { + let consumer = test_consumer(); + let schema = DFSchema::empty(); + let nested = Nested { + nullable: true, + type_variation_reference: 0, + nested_type: Some(NestedType::List(List { values: vec![] })), + }; + + let expr = from_nested(&consumer, &nested, &schema).await?; Review Comment: I think we might want to reject empty nested lists actual > // A homogeneously-typed list of one or more expressions that form the // list entries. To specify an empty list, use Literal.empty_list // (otherwise type information would be missing). [from](https://github.com/substrait-io/substrait/blob/150d86d10ce10384685513715c78d63a9a6c1e37/proto/substrait/algebra.proto#L1185-L1189) If the list is empty, we don't have a type for it's elements. I don't know how that works for Arrow, but that type is malformed in Substrait. ########## datafusion/substrait/tests/testdata/test_plans/nested_list_expressions.substrait.json: ########## @@ -0,0 +1,92 @@ +{ + "extensionUris": [ + { + "extensionUriAnchor": 1, + "uri": "https://github.com/substrait-io/substrait/blob/main/extensions/functions_arithmetic.yaml"; + } + ], + "extensions": [ + { + "extensionFunction": { + "extensionUriReference": 1, + "functionAnchor": 0, + "name": "add:i32_i32" + } Review Comment: You included a function in this plan, but it's never used. Did you intend to use it when constructing the list below? -- This is an automated message from the Apache Git Service. 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