Audit Wheel Dependencies

[tarang-jain]

Drops depends_on_nccl from the libraft wheel's build and runtime
requirement groups (py_rapids_build_libraft, py_run_libraft) in
dependencies.yaml.

More changes on 07/22/2026:
libraft and libraft-static dont need to depend on the complete libraft-headers (there are no multi-gpu targets etc). Further raft-dask seems like the only target that needs the cmake flag for nccl

Addresses #2977.

[coderabbitai]

📝 Walkthrough

Walkthrough

LibRAFT dependency groups, wheel build arguments, and conda recipes are updated. NCCL runtime wheel configuration is restricted to raft-dask, header-only package requirements are adopted, and obsolete dependency declarations are removed.

Changes

LibRAFT packaging updates

Layer / File(s)	Summary
Update LibRAFT dependency includes dependencies.yaml	LibRAFT dependency groups replace depends_on_nccl with depends_on_librmm and depends_on_rapids_logger.
Scope wheel build arguments ci/build_wheel.sh	The NCCL runtime wheel CMake argument is exported only when building raft-dask; the SPDX header is updated.
Update conda package requirements conda/recipes/libraft/recipe.yaml, conda/recipes/pylibraft/recipe.yaml	The libraft and libraft-static packages switch to exact libraft-headers-only requirements, remove cuda-profiler-api, and update the pylibraft recipe to remove libraft-headers.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: msarahan

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
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.
Title check	✅ Passed	The title matches the main theme of changing wheel and dependency requirements.
Description check	✅ Passed	The description is clearly related to the dependency and build-flag changes in the PR.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[bdice]

Why is this changed? What is the specific difference in host/run pinnings that you are aiming to produce?

[bdice]

Summary of the impact from AI:

libraft-headers depends on libraft-headers-only, so selecting it also installs the latter's cuda-version, librmm, and rapids-logger dependencies. Relative to that shared closure, libraft-headers additionally brings cuda-profiler-api, libcublas-dev, libcurand-dev, libcusolver-dev, libcusparse-dev, nccl >=2.19, and ucxx 0.52.\*.

Consequently, replacing libraft-headers with libraft-headers-only avoids the four CUDA development packages plus nccl and ucxx. The runtime CUDA libraries are not removed from libraft or libraft-static: both packages continue to directly require libcublas, libcurand, libcusolver, and libcusparse. cuda-profiler-api is also directly removed from those two packages in PR 3091, rather than being removed solely through the header-package substitution.

So basically this means that depending on libraft is no longer enough to build other libraries against libraft, because you don't have CUDA math library dev packages. This is a regression.

[tarang-jain]

My understanding is that the libraft package only contains a few source files in the raft_runtime directory:

add_library(
    raft_objs OBJECT
    src/raft_runtime/random/rmat_rectangular_generator_int64_double.cu
    src/raft_runtime/random/rmat_rectangular_generator_int64_float.cu
    src/raft_runtime/random/rmat_rectangular_generator_int_double.cu
    src/raft_runtime/random/rmat_rectangular_generator_int_float.cu
    src/raft_runtime/solver/lanczos_solver_int64_double.cu
    src/raft_runtime/solver/lanczos_solver_int64_float.cu
    src/raft_runtime/solver/lanczos_solver_int_double.cu
    src/raft_runtime/solver/lanczos_solver_int_float.cu
  )

I think any downstream package should depend on libraft-headers and not libraft

[tarang-jain]

the important question is -- what do we need the libraft pkg to represent -- only the compiled source files or all the packages required to include any header in this repo?

[tarang-jain]

Looking at the description here:
https://pypi.org/project/libraft-cu12/#:~:text=RAFT%20is%20a,GPU%20with%20Dask.

I think this PR is in the right direction -- libraft's shared library should be C++ only. I'll wait for others / PICs to weigh in.