findepi commented on code in PR #14519: URL: https://github.com/apache/datafusion/pull/14519#discussion_r1944351361
########## datafusion/core/src/schema_equivalence.rs: ########## @@ -0,0 +1,84 @@ +// 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::{DataType, Field, Fields, Schema}; + +/// Verifies whether the original planned schema can be satisfied with data +/// adhering to the candidate schema. In practice, this is equality check on the +/// schemas except that original schema can have nullable fields where candidate +/// is constrained to not provide null data. +pub(crate) fn schema_satisfied_by(original: &Schema, candidate: &Schema) -> bool { + original.metadata() == candidate.metadata() + && fields_satisfied_by(original.fields(), candidate.fields()) +} + +/// See [`schema_satisfied_by`] for the contract. +fn fields_satisfied_by(original: &Fields, candidate: &Fields) -> bool { + original.len() == candidate.len() + && original + .iter() + .zip(candidate) Review Comment: i don't think it's legal. eg If we promised SELECT to return a,b,c we cannot return b,a,c order -- 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...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
