[BUG]: LinkerOptions(numba_debug=True) is silently dropped

[rparolin]

Type of Bug

Silent incorrect behavior (no error raised)

Component

cuda.core

Describe the bug

LinkerOptions.numba_debug (cuda_core/cuda/core/_linker.pyx:309) is declared as a public field but is never emitted by either backend. Neither _prepare_nvjitlink_options nor _prepare_driver_options references it, so setting it has no effect and no error.

This is not merely a dead field. _translate_program_options (cuda_core/cuda/core/_program.pyx:745) actively forwards numba_debug from ProgramOptions into LinkerOptions:

return LinkerOptions(
    ...
    no_cache=options.no_cache,
    numba_debug = options.numba_debug
)

That translation runs on the code_type == "ptx" path of Program, so Program(ptx, "ptx", ProgramOptions(numba_debug=True)) also drops the option. It is a silent drop on a live code path, which conflicts with the repository's "no silent failures" guidance: an option the user explicitly set should either take effect or raise, not vanish.

Introduced in #2158 (792ab3c9fea), the same change that added numba_debug to ProgramOptions. The NVVM half of that feature was separately broken and is fixed in #2639; this linker half is untouched by that PR.

How to Reproduce

from cuda.core import LinkerOptions

o = LinkerOptions(arch="sm_80", debug=True, numba_debug=True)
print(o.numba_debug)                              # True
print(o._prepare_nvjitlink_options(as_bytes=True))

True
[b'-arch=sm_80', b'-g']

The field is True, but no corresponding option is emitted. grep -n numba cuda_core/cuda/core/_linker.pyx returns only the field declaration.

Expected behavior

One of:

1. Emit the option on the paths that support it, matching the ProgramOptions NVVM fix in fix(cuda.core): emit -numba-debug with a single dash for NVVM #2639, or
2. Raise if numba_debug is set on a backend that cannot honor it, consistent with how _prepare_nvvm_options_impl raises CUDAError for options the NVVM backend does not support, or
3. Remove the field if it was never meant to be plumbed through the linker, and stop _translate_program_options from forwarding it.

Whichever is chosen, a user-set option should not disappear without a diagnostic.

Operating System

Linux, CUDA 13.3 (reproduced against main)