Migrate stream APIs from rmm::cuda_stream_view to cuda::stream_ref

[bdice]

Summary

Track the coordinated migration of stream APIs and call sites from rmm::cuda_stream_view to CCCL's cuda::stream_ref. This propagates cuda::stream_ref through RMM containers and memory resources, RAFT resource and handle APIs, downstream C++ interfaces, Python/Cython bindings, benchmarks, tests, and documentation.

This updates cuDF C++ and Cython stream accessors, building on the default-stream work merged in #23770. It continues work from #23636.

Depends on rapidsai/rmm#2372.

Tracked in rapidsai/build-planning#318.

Migrations

• Pass cuda::stream_ref through stream pools, resource accessors, conditionals, and downstream APIs without converting to rmm::cuda_stream_view
• Use cuda::stream_ref constructions for default/legacy/per-thread streams
  • rmm::cuda_stream_default ➡️ cuda::stream_ref{cudaStream_t{cudaStreamDefault}}
  • rmm::cuda_stream_legacy ➡️ cuda::stream_ref{cudaStreamLegacy}
  • rmm::cuda_stream_per_thread ➡️ cuda::stream_ref{cudaStreamPerThread}
• Use .get() when calling an API that requires a raw cudaStream_t, including CUDA runtime, library, CUB, and legacy API boundaries (previously rmm::cuda_stream_view used value())
• Use .sync() when synchronizing a cuda::stream_ref (previously rmm::cuda_stream_view used synchronize())
• Update Cython declarations and call sites to pass stream references directly where supported

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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📒 Files selected for processing (3)

• cpp/libcudf_streaming/src/bloom_filter.cpp
• cpp/tests/scalar/scalar_test.cpp
• python/pylibcudf/pylibcudf/io/parquet_io_utils.pyx

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📝 Summary

Summary by CodeRabbit

• Bug Fixes
  • Updated CUDA stream handling across GPU-accelerated operations, including joins, sorting, aggregation, text processing, string operations, and file I/O.
  • Improved compatibility with current CUDA stream interfaces across C++, Python, and Java integrations.
  • Preserved existing public APIs, validation, processing behavior, and results while improving stream interoperability.

Walkthrough

Changes

The pull request replaces deprecated CUDA stream headers and accessors across C++, Java native code, and Python Cython bindings. It also passes stream views directly in streaming helpers and updates Parquet remapping to use cuda::stream_ref.

CUDA stream migration

Layer / File(s)	Summary
Native stream contracts cpp/include/cudf/..., cpp/src/..., cpp/tests/..., java/src/main/native/...	CUDA stream includes now use <cuda/stream>. The Parquet dictionary remapping function now accepts cuda::stream_ref.
Python stream access python/cudf_streaming/..., python/pylibcudf/...	Cython bindings replace .value() with .get() and pass stream views directly where supported. Operation behavior and public signatures remain unchanged.

Estimated code review effort: 2 (Simple) | ~15 minutes

Merge Risk: ⚪ Minimal · up to bb9fc

This update completes stream-reference API compatibility at the affected native, test, and Parquet binding call sites without changing intended stream behavior. No concrete merge-blocking risk remains.

Possibly related PRs

• NVIDIA/cudf#23727: Migrates related CUDA stream headers, types, and accessors.

Suggested labels: improvement, non-breaking

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 15 files. (1 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the primary change: migrating stream APIs from rmm::cuda_stream_view to cuda::stream_ref.
Description check	✅ Passed	The description directly explains the stream API migration and covers the updated C++ and Cython call sites shown in the changeset.
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.

Full details: Docstring Coverage

Explanation

Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 15 files. (1 skipped: 1 unsupported.)

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✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests

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