feat(python): support row indices in VortexFile.to_arrow

[joseph-isaacs]

Summary

VortexFile.to_arrow cannot select row indices even though scan and prepare support them. Add the indices argument to the Python API and binding, using the same scan builder and strictly increasing, non-null index validation.

Changes

New cases cover empty and sparse selections, nullable strings, requested ordinary-string schemas, scan-equivalent batching, filtering, limits, and invalid indices. The existing restriction on combined filters and limits is preserved. Existing tests remain unchanged.

API Changes

Adds the optional keyword argument indices: vortex.Array | None to VortexFile.to_arrow(). Indices must be strictly increasing and non-null, matching scan() and prepare().

Validation

• python -m pytest vortex-python/test/test_file_arrow_indices.py vortex-python/test/test_file.py -q — 21 passed.

[codspeed]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ 1 benchmark measured no execution time

Nothing ran under measurement, usually because the compiler removed the code under test. This result is not comparable, so it counts as unchanged.

Preventing compiler optimizations

✅ 2187 untouched benchmarks
⏩ 518 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚠️	Simulation	density_sweep_dense_runs[0.9]	< 1 ns	< 1 ns	N/A

---

_{Comparing ji/python-arrow-row-indices (b11910e) with develop (ceeeff7)²}

Footnotes

1. 518 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on develop (e6668f5) during the generation of this report, so ceeeff7 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[robert3005]

you're missing types

ANN201 Missing return type annotation for public function `indexed_file`
  --> vortex-python/test/test_file_arrow_indices.py:14:5
   |
13 | @pytest.fixture
14 | def indexed_file(tmp_path: Path):
   |     ^^^^^^^^^^^^
15 |     table = pa.table(
16 |         {
   |
help: Add return type annotation