Better error reporting with std::source_location

[achirkin]

Rewrite error message macros using C++20 std::source_location.
Using std::source_location gives two advantages over macros:

1. Give the enclosing function name with an exact instantiation types in addition to the line/file info.
2. Propagating the location explicitly from the call site to allow utility function report errors on behalf of the callers.

The point (2) has been a big pain point over the years of raft and cuvs development: small utility functions like raft::resource::sync_stream use RAFT_CUDA_TRY macro under the hood, so they report their internal source location on error. See the example below.

Before (not clear where the error comes from):

CUDA error encountered at: file=/home/achirkin/workspace/raft/cpp/include/raft/core/interruptible.hpp line=294: call='query_result', Reason=cudaErrorIllegalAddress:an illegal memory access was encountered
Obtained 6 stack frames
#1 in ./build/repro(+0xfd0d) [0x62b9a3ed9d0d]
#2 in ./build/repro(+0x11337) [0x62b9a3edb337]
#3 in ./build/repro(+0xc3fa) [0x62b9a3ed63fa]
#4 in /usr/lib/x86_64-linux-gnu/libc.so.6(+0x2a1ca) [0x7d03d6c1d1ca]
#5 in /usr/lib/x86_64-linux-gnu/libc.so.6: __libc_start_main +0x8b [0x7d03d6c1d28b]
#6 in ./build/repro(+0xc60e) [0x62b9a3ed660e]

After (exact line and function instance is visible immediately):

CUDA error encountered at: file=/home/achirkin/workspace/raft/example/main.cu line=12 function=void run_broken_kernel(raft::resources&) [with T = float]: call='cudaStreamQuery', Reason=cudaErrorIllegalAddress:an illegal memory access was encountered
Obtained 5 stack frames
#1 in ./build/repro(+0x10a6a) [0x5c16f83b2a6a]
#2 in ./build/repro(+0xc3ca) [0x5c16f83ae3ca]
#3 in /usr/lib/x86_64-linux-gnu/libc.so.6(+0x2a1ca) [0x7a860027d1ca]
#4 in /usr/lib/x86_64-linux-gnu/libc.so.6: __libc_start_main +0x8b [0x7a860027d28b]
#5 in ./build/repro(+0xc5de) [0x5c16f83ae5de]

Reproducer:

#include <raft/core/resource/cuda_stream.hpp>
#include <raft/core/resources.hpp>
#include <raft/util/kernel_launch.hpp>

template <typename T>
__global__ void broken_kernel(T* out) { *out = 42; }

template <typename T>
void run_broken_kernel(raft::resources& res)
{
  raft::launch_kernel(res, 1, 1, broken_kernel<T>, nullptr);
  raft::resource::sync_stream(res);
}

int main()
{
  raft::resources res;

  try {
    run_broken_kernel<float>(res);
  } catch (raft::exception const& e) {
    std::cout << e.what() << std::endl;
  }
}

Breaking Change

The PR adds default-value argument std::source_location loc = std::source_location::current() to a few existing public functions. This doesn't change how these function are called, but is technically a breaking change (e.g. passing something like raft::resource::sync_stream by its function pointer would have to be adjusted). I haven't found any affected use cases in the known downstream projects.

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• cpp/include/raft/util/cuda_rt_essentials.hpp

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• cpp/include/raft/util/cuda_rt_essentials.hpp

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---

📝 Walkthrough

Summary by CodeRabbit

• New Features

  • Error messages now include the originating file, line, and function for easier troubleshooting.
  • CUDA, synchronization, and interruption errors provide improved call-site context.
  • Added consistent CUDA error checking and printf-style format validation.

• Documentation

  • Updated developer guidance for source-location-aware error handling and deprecated error macros.

• Tests

  • Added coverage for formatted errors, caller attribution, CUDA failures, synchronization, and interruption handling.

Walkthrough

The change adds source-location-aware error formatting, centralizes CUDA error handling, propagates call-site locations through synchronization APIs, updates library error macros, and adds tests and developer guidance.

Changes

Error reporting and source-location propagation

Layer / File(s)	Summary
Error formatting contracts and macros cpp/include/raft/core/error.hpp, cpp/include/raft/core/detail/macros.hpp	Adds raft::format_error_message, source-location formatting, printf-format annotations, and direct use by RAFT_EXPECTS and RAFT_FAIL. SET_ERROR_MSG now delegates to a deprecated formatter.
CUDA and library error integration cpp/include/raft/util/cuda_rt_essentials.hpp, cpp/include/raft/util/kernel_launch.hpp, cpp/include/raft/common/nccl_macros.hpp, cpp/include/raft/core/*blas_macros.hpp, cpp/include/raft/core/cusolver_macros.hpp, cpp/include/raft/core/cusparse_macros.hpp	Adds raft::check_cuda_error, uses it for kernel launch errors, and updates NCCL, cuBLAS, cuSOLVER, and cuSPARSE error macros to format messages with source locations.
Synchronization source-location propagation cpp/include/raft/core/device_resources.hpp, cpp/include/raft/core/interruptible.hpp, cpp/include/raft/core/resource/*.hpp, cpp/include/raft/core/stream_view.hpp	Adds optional std::source_location parameters and forwards them through stream, event, resource, and interruptible synchronization paths.
Validation and developer guidance cpp/tests/core/error.cpp, cpp/tests/core/interruptible.cu, cpp/tests/util/cudart_utils.cpp, cpp/tests/CMakeLists.txt, docs/source/developer_guide.md	Adds message and caller-attribution tests, includes the new test source in both test targets, and documents source-location forwarding and SET_ERROR_MSG deprecation.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: 🟡 Moderate · up to 30a44

This PR improves CUDA error locations and caller context, but the current head still risks buffer under-allocation during error formatting, compatibility breaks for existing callback or function-pointer users, and hidden CUDA cleanup failures with retained graph resources. Merge should wait for fixes or explicit owner acceptance.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 36.00% 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
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 clearly and concisely describes the primary change: improved error reporting using C++20 std::source_location.
Description check	✅ Passed	The description directly explains the std::source_location changes, benefits, affected utilities, examples, and compatibility considerations.

✨ Finishing Touches

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• Create PR with unit tests

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Actionable comments posted: 3

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Inline comments:
In `@cpp/include/raft/core/error.hpp`:
- Around line 68-74: Update try_vformat_error_message to compute all buffer-size
additions with checked std::size_t arithmetic before allocation, returning false
on overflow. Catch std::vector and std::string allocation failures and preserve
the no-throw return contract; ensure every caller performs va_end on both
success and failure paths, including exception paths.

In `@cpp/include/raft/core/interruptible.hpp`:
- Around line 79-100: Preserve the existing callable types by removing defaulted
source_location parameters from the public overloads. In
cpp/include/raft/core/interruptible.hpp lines 79-100 and 120-123, retain the
existing synchronize and yield signatures and add separate location-aware APIs;
apply the same pattern to resource::sync_stream and resource::sync_stream_view
in cpp/include/raft/core/resource/cuda_stream.hpp lines 89-107, and
stream_view::interruptible_synchronize in cpp/include/raft/core/stream_view.hpp
lines 81-85. Apply the equivalent split to device_resources::sync_stream,
keeping existing overload behavior while providing explicit location forwarding.

Apply the same fix in `@cpp/include/raft/core/device_resources.hpp` around lines
121 - 135: Covers the affected device_resources and resource synchronization
overloads.

In `@cpp/tests/core/interruptible.cu`:
- Around line 109-115: Update ~capturing_stream() to inspect the result of
cudaStreamEndCapture: explicitly accept cudaErrorStreamCaptureInvalidated with a
null graph, destroy graph only when capture ends successfully, and route any
other CUDA error through no-throw RAFT error handling instead of clearing it
with cudaGetLastError().

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Configuration used: Path: .coderabbit.yaml

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📥 Commits

Reviewing files that changed from the base of the PR and between c864265 and 010ff14.

📒 Files selected for processing (18)

• cpp/include/raft/common/nccl_macros.hpp
• cpp/include/raft/core/cublas_macros.hpp
• cpp/include/raft/core/cusolver_macros.hpp
• cpp/include/raft/core/cusparse_macros.hpp
• cpp/include/raft/core/detail/macros.hpp
• cpp/include/raft/core/device_resources.hpp
• cpp/include/raft/core/error.hpp
• cpp/include/raft/core/interruptible.hpp
• cpp/include/raft/core/resource/cuda_stream.hpp
• cpp/include/raft/core/resource/stream_view.hpp
• cpp/include/raft/core/stream_view.hpp
• cpp/include/raft/util/cuda_rt_essentials.hpp
• cpp/include/raft/util/kernel_launch.hpp
• cpp/tests/CMakeLists.txt
• cpp/tests/core/error.cpp
• cpp/tests/core/interruptible.cu
• cpp/tests/util/cudart_utils.cpp
• docs/source/developer_guide.md

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[achirkin]

/merge