Remove _driver_ver from _linker.pyx; use _use_nvjitlink_backend as guard

Initialize _use_nvjitlink_backend to None so it can serve as its own
"already decided" sentinel, eliminating the redundant _driver_ver variable
and the driver_version() call that was only used to set it.

Made-with: Cursor

Author: Andy-Jost

cuda_core/cuda/core/_linker.pyx

@@ -39,7 +39,6 @@ from cuda.core._utils.cuda_utils import (
     driver,
     is_sequence,
 )
-from cuda.core._utils.version import driver_version
 
 ctypedef const char* const_char_ptr
 ctypedef void* void_ptr
@@ -620,9 +619,8 @@ cdef inline void Linker_annotate_error_log(Linker self, object e):
 
 # TODO: revisit this treatment for py313t builds
 _driver = None  # populated if nvJitLink cannot be used
-_driver_ver = None
 _inited = False
-_use_nvjitlink_backend = False  # set by _decide_nvjitlink_or_driver()
+_use_nvjitlink_backend = None  # set by _decide_nvjitlink_or_driver()
 
 # Input type mappings populated by _lazy_init() with C-level enum ints.
 _nvjitlink_input_types = None
@@ -637,12 +635,10 @@ def _nvjitlink_has_version_symbol(nvjitlink) -> bool:
 # Note: this function is reused in the tests
 def _decide_nvjitlink_or_driver() -> bool:
     """Return True if falling back to the cuLink* driver APIs."""
-    global _driver_ver, _driver, _use_nvjitlink_backend
-    if _driver_ver is not None:
+    global _driver, _use_nvjitlink_backend
+    if _use_nvjitlink_backend is not None:
         return not _use_nvjitlink_backend
 
-    _driver_ver = driver_version()[:2]
-
     warn_txt_common = (
         "the driver APIs will be used instead, which do not support"
         " minor version compatibility or linking LTO IRs."
@@ -667,6 +663,7 @@ def _decide_nvjitlink_or_driver() -> bool:
         )
 
     warn(warn_txt, stacklevel=2, category=RuntimeWarning)
+    _use_nvjitlink_backend = False
     _driver = driver
     return True
 

cuda_core/tests/test_optional_dependency_imports.py

@@ -12,23 +12,20 @@ def restore_optional_import_state():
     saved_nvvm_module = _program._nvvm_module
     saved_nvvm_attempted = _program._nvvm_import_attempted
     saved_driver = _linker._driver
-    saved_driver_ver = _linker._driver_ver
     saved_inited = _linker._inited
     saved_use_nvjitlink = _linker._use_nvjitlink_backend
 
     _program._nvvm_module = None
     _program._nvvm_import_attempted = False
     _linker._driver = None
-    _linker._driver_ver = None
     _linker._inited = False
-    _linker._use_nvjitlink_backend = False
+    _linker._use_nvjitlink_backend = None
 
     yield
 
     _program._nvvm_module = saved_nvvm_module
     _program._nvvm_import_attempted = saved_nvvm_attempted
     _linker._driver = saved_driver
-    _linker._driver_ver = saved_driver_ver
     _linker._inited = saved_inited
     _linker._use_nvjitlink_backend = saved_use_nvjitlink
 
@@ -79,8 +76,6 @@ def fake__optional_cuda_import(modname, probe_function=None):
 
 
 def test_decide_nvjitlink_or_driver_reraises_nested_module_not_found(monkeypatch):
-    monkeypatch.setattr(_linker, "driver_version", lambda: (13, 0, 0))
-
     def fake__optional_cuda_import(modname, probe_function=None):
         assert modname == "cuda.bindings.nvjitlink"
         assert probe_function is not None
@@ -96,8 +91,6 @@ def fake__optional_cuda_import(modname, probe_function=None):
 
 
 def test_decide_nvjitlink_or_driver_falls_back_when_module_missing(monkeypatch):
-    monkeypatch.setattr(_linker, "driver_version", lambda: (13, 0, 0))
-
     def fake__optional_cuda_import(modname, probe_function=None):
         assert modname == "cuda.bindings.nvjitlink"
         assert probe_function is not None