Support pl.Expr.dt.quarter

[mroeschke]

Description

xref #23151

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 1fd7e48 and 332a86a.

📒 Files selected for processing (2)

• python/cudf_polars/cudf_polars/dsl/expressions/datetime.py
• python/cudf_polars/tests/expressions/test_datetime_basic.py

🚧 Files skipped from review as they are similar to previous changes (2)

• python/cudf_polars/tests/expressions/test_datetime_basic.py
• python/cudf_polars/cudf_polars/dsl/expressions/datetime.py

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📝 Walkthrough

Summary by CodeRabbit

• New Features
  • Added support for extracting the quarter from Date and Datetime values.
  • Works across supported datetime resolutions (ms/us/ns) and returns correct results for nullable inputs.
• Tests
  • Added GPU-backed test coverage to verify .dt.quarter() for Date and Datetime types, including null handling, by comparing results against expected output.

Walkthrough

Adds support for the Quarter temporal operation in TemporalFunction, including evaluation via extract_quarter and a new parametrized test covering Date and Datetime dtypes.

Changes

Quarter Temporal Function Support

Layer / File(s)	Summary
Quarter operation implementation and validation python/cudf_polars/cudf_polars/dsl/expressions/datetime.py, python/cudf_polars/tests/expressions/test_datetime_basic.py	Quarter is added to _valid_ops, evaluated through plc.datetime.extract_quarter with a cast to the target dtype, and covered by a new parametrized .dt.quarter() test across Date and Datetime inputs.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• rapidsai/cudf#18443: Both PRs extend TemporalFunction with new _valid_ops entries and do_evaluate branches for temporal operations, with corresponding tests in test_datetime_basic.py.
• rapidsai/cudf#23153: Both PRs add a new .dt.* operation to TemporalFunction and validate it with GPU tests in test_datetime_basic.py.
• rapidsai/cudf#23154: Both PRs update the same TemporalFunction datetime expression handling with a new temporal extraction path and test coverage.

Suggested reviewers: bdice, rjzamora

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly matches the main change: adding support for pl.Expr.dt.quarter.
Description check	✅ Passed	The description references the linked issue and is clearly about the same quarter-support change.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Matt711]

Can you keep #16481 updated as you go?

[mroeschke]

/merge