Add TableSchema helper to encapsulate file schema + partition fields

[adriangb]

Hoping this helps with #14993

[Copilot]

Pull Request Overview

This PR introduces a TableSchema helper struct to better encapsulate file schema and partition field information within FileScanConfig. The refactoring consolidates the previously separate file_schema and table_partition_cols fields into a single table_schema field of type TableSchema, which manages both components and provides accessor methods.

Key changes:

• Introduced TableSchema struct in datafusion/common/src/dfschema.rs to encapsulate file schema, partition columns, and the combined table schema
• Refactored FileScanConfig to use TableSchema instead of separate file_schema and table_partition_cols fields
• Updated all references throughout the codebase to use accessor methods (file_schema(), table_partition_cols())

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
datafusion/common/src/dfschema.rs	Adds new TableSchema struct with file schema, partition columns, and combined table schema
datafusion/common/src/lib.rs	Exports TableSchema from the dfschema module
datafusion/datasource/src/file_scan_config.rs	Refactors FileScanConfig to use TableSchema and adds accessor methods
datafusion/datasource/src/file_stream.rs	Updates field access to use table_partition_cols() method
datafusion/datasource-parquet/src/source.rs	Updates field access to use file_schema() and table_partition_cols() methods
datafusion/proto/src/physical_plan/to_proto.rs	Updates field access to use accessor methods
datafusion-testing	Updates subproject commit reference

Comments suppressed due to low confidence (1)

datafusion/datasource/src/file_scan_config.rs:1

• [nitpick] The new TableSchema struct and its purpose should be documented in the module-level documentation to help users understand when and how to use it versus directly working with schemas.

// Licensed to the Apache Software Foundation (ASF) under one

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[alamb]

Did you mean to update the pin in datafusion-testing? I suspect this was not intended

[alamb]

Thanks @adriangb -- I think this is a significant improvement 🙏

I think we need to fix the datafusion-testing pin before merging this PR, otherwise the rest of the comments aren't necessary in my mind

I do think moving this structure into datafusion-datasource would align it better with its use

[alamb]

This is a good structure

It seems pretty specific to the DataSource code, so I suggest putting it in the datasource module. Maybe alongside FileScanConfig in datafusion/datasource/src/file_scan_config.rs or its own module datafusion/datasource/src/table_schema.rs