Support inferring schemas from Python dataclasses

[Abacn]

Fix #22085

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Summary of Changes

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This pull request enhances Apache Beam's type hinting capabilities by introducing comprehensive support for Python dataclasses. It enables the system to recognize, convert, and infer schemas from dataclasses, integrating them seamlessly into Beam's data processing model, similar to how NamedTuples are handled.

Highlights

• Dataclass Recognition: A new utility function, match_is_dataclass, was added to accurately identify Python dataclass types within the type hinting system.
• Type Conversion Integration: The convert_to_beam_type mechanism was updated to include dataclass recognition, allowing Beam to properly process and convert dataclass types.
• RowType Constraint Generation: The RowTypeConstraint.from_user_type method was extended to correctly extract fields and their types from dataclasses, facilitating the generation of Beam schemas.
• Schema Inference Update: The schema_from_element_type function was modified to infer schemas directly from dataclasses, providing consistent behavior with existing NamedTuple support.
• Comprehensive Testing: New unit tests were introduced to validate the roundtrip conversion of dataclasses to Beam schemas and to ensure their correct schema inference.

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Changelog

• sdks/python/apache_beam/typehints/native_type_compatibility.py
  • Imported the dataclasses module.
  • Added a new function match_is_dataclass to check if a type is a dataclass.
  • Updated convert_to_beam_type to include a _TypeMapEntry for dataclasses.
• sdks/python/apache_beam/typehints/row_type.py
  • Imported match_is_dataclass from native_type_compatibility.
  • Extended the from_user_type static method to handle dataclass types, extracting their fields and types to construct RowTypeConstraint instances.
• sdks/python/apache_beam/typehints/schemas.py
  • Imported match_is_dataclass from native_type_compatibility.
  • Modified schema_from_element_type to infer schemas from dataclasses, alongside named tuples.
• sdks/python/apache_beam/typehints/schemas_test.py
  • Imported the dataclasses module.
  • Added test_dataclass_roundtrip to verify the conversion of dataclasses to RowTypeConstraint and schema generation.
  • Added test_trivial_example_dataclass to test the schema inference for a basic dataclass structure.

Activity

• Addressed issue [Feature Request]: Support for inferring schemas from Python dataclasses #22085.
• Included a standard contribution checklist in the pull request description.

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