[BUG]: LocatedHeaderDir is mutable, so callers can poison the cached header-directory lookup

Bắt đầu từ định nghĩa LocatedHeaderDir và các điểm vào locate_nvidia_header_directory() và find_nvidia_header_directory(). So sánh phần triển khai với _static_libs/find_static_lib.py và _static_libs/find_bitcode_lib.py, sau đó chạy các bài kiểm thử cuda.pathfinder. Hoàn thành khi kết quả là bất biến và hashable mà không thay đổi hành vi tra cứu.

Component

cuda.pathfinder

What happened?

locate_nvidia_header_directory() is @functools.cache-backed and returns LocatedHeaderDir, which is a plain (mutable) dataclass. The cache hands every caller the same object, so a write to abs_path on a returned instance changes what every later lookup of that libname returns for the rest of the process, including through the find_nvidia_header_directory() wrapper.

LocatedHeaderDir is also the only one of the three public Located* return types that behaves this way: LocatedStaticLib (_static_libs/find_static_lib.py) and LocatedBitcodeLib (_static_libs/find_bitcode_lib.py) are both @dataclass(frozen=True). As a side effect of not being frozen, LocatedHeaderDir is also unhashable, so it cannot be put in a set or used as a dict key the way its two siblings can.

Reproduction

from cuda.pathfinder import locate_nvidia_header_directory, find_nvidia_header_directory

first = locate_nvidia_header_directory("cudart")
print(first.abs_path)                                # e.g. /usr/local/cuda/include

first.abs_path = "/somewhere/else"                   # caller "normalizes" the result in place

print(locate_nvidia_header_directory("cudart").abs_path)  # /somewhere/else
print(find_nvidia_header_directory("cudart"))             # /somewhere/else

>>> LocatedHeaderDir.__dataclass_params__.frozen, LocatedHeaderDir.__hash__ is not None
(False, False)
>>> LocatedStaticLib.__dataclass_params__.frozen, LocatedStaticLib.__hash__ is not None
(True, True)
>>> LocatedBitcodeLib.__dataclass_params__.frozen, LocatedBitcodeLib.__hash__ is not None
(True, True)

Suggested fix

Make LocatedHeaderDir @dataclass(frozen=True) so it matches the other two public Located* types. The __post_init__ path normalization then needs object.__setattr__. Nothing inside cuda_pathfinder or its tests mutates a LocatedHeaderDir, so this is contained to the public type's contract.