Use forward_property for property forwarding in resource_ref wrappers

[bdice]

Description

Replace the hand-rolled friend get_property templates in cccl_resource_ref and cccl_async_resource_ref with inheritance from cuda::forward_property. This delegates property forwarding to CCCL's own machinery, which correctly handles dynamic_accessibility_property (NVIDIA/cccl#7727) and any future properties without ambiguity.

Each wrapper now exposes upstream_resource() returning the inner ResourceType, as required by forward_property for stateful properties.

Tests add minimal forward_property adaptors using RMM resource refs as upstream, exercising the exact scenario that causes the ambiguity.

Note: this is a temporary solution for the main branch -- resolving #2323 / #2325 will remove this code on the staging branch while I continue working on CCCL MR migrations.

Closes #2322.

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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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 1bef459 and 8cedbad.

📒 Files selected for processing (2)

• cpp/include/rmm/detail/cccl_adaptors.hpp
• cpp/tests/mr/resource_ref_conversion_tests.cpp

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📝 Walkthrough

Summary by CodeRabbit

• Refactor

  • Updated internal resource reference classes to improve property forwarding capabilities and better align with CUDA memory resource standards.
  • Simplified property delegation mechanisms through modernized accessor patterns to enhance code maintainability and clarity.

• Tests

  • Added comprehensive validation tests for resource reference type erasure, property forwarding behavior, and async/sync resource adaptor patterns.

Walkthrough

The PR refactors property forwarding in two CCCL adaptor classes (cccl_resource_ref and cccl_async_resource_ref) by replacing friend get_property templates with public inheritance from cuda::forward_property and introducing upstream_resource() accessor methods.

Changes

Cohort / File(s)	Summary
CCCL Adaptor Property Forwarding cpp/include/rmm/detail/cccl_adaptors.hpp	Updated cccl_resource_ref and cccl_async_resource_ref to inherit from cuda::forward_property<> and removed friend get_property templates in favor of upstream_resource() const accessor methods returning ResourceType const&.
Property Forwarding Validation Tests cpp/tests/mr/resource_ref_conversion_tests.cpp	Added forwarding adaptor structs wrapping RMM resource refs, validated cuda::forward_property concept compliance via static_assert, and introduced three test cases for type-erasure and property access through the forwarding chain.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related issues

• Ambiguous get_property overload with CCCL's dynamic_accessibility_property #2322 — This PR directly resolves the ambiguous get_property overload with CCCL's dynamic_accessibility_property by replacing the unconstrained friend template with cuda::forward_property inheritance.

Possibly related PRs

• Remove rmm::detail::polyfill in favor of CCCL concepts, require CCCL >=3.3 #2283 — Modified the same header file (cpp/include/rmm/detail/cccl_adaptors.hpp) to remove polyfill includes.

Suggested labels

non-breaking, improvement

Suggested reviewers

• harrism
• rongou
• ttnghia

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 22.73% which is insufficient. The required threshold is 80.00%.	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 'Use forward_property for property forwarding in resource_ref wrappers' accurately summarizes the main change: replacing hand-rolled friend get_property templates with cuda::forward_property inheritance.
Description check	✅ Passed	The description clearly explains the motivation (resolving ambiguity with CCCL's dynamic_accessibility_property), the implementation approach (inheritance from cuda::forward_property, adding upstream_resource()), and references the related issue (#2322).
Linked Issues check	✅ Passed	The PR directly addresses issue #2322 by replacing unconstrained friend get_property templates with cuda::forward_property inheritance and adding upstream_resource() accessors, which eliminates the ambiguity in property overload resolution.
Out of Scope Changes check	✅ Passed	Changes are focused and in-scope: modifications to cccl_resource_ref and cccl_async_resource_ref in cccl_adaptors.hpp, and test additions using forward_property adaptors to validate the solution, all directly supporting the stated objective.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[bdice]

/merge