Add LoadedDL.found_via

cuda_pathfinder/cuda/pathfinder/_dynamic_libs/load_dl_common.py

@@ -16,6 +16,7 @@ class LoadedDL:
     abs_path: Optional[str]
     was_already_loaded_from_elsewhere: bool
     _handle_uint: int  # Platform-agnostic unsigned pointer value
+    foundvia: Optional[str] = None
 
 
 def load_dependencies(libname: str, load_func: Callable[[str], LoadedDL]) -> None:

cuda_pathfinder/cuda/pathfinder/_dynamic_libs/load_dl_linux.py

@@ -138,7 +138,9 @@ def check_if_already_loaded_from_elsewhere(libname: str, _have_abs_path: bool) -
         except OSError:
             continue
         else:
-            return LoadedDL(abs_path_for_dynamic_library(libname, handle), True, handle._handle)
+            return LoadedDL(
+                abs_path_for_dynamic_library(libname, handle), True, handle._handle, "already-loaded-from-elsewhere"
+            )
     return None
 
 
@@ -170,7 +172,7 @@ def load_with_system_search(libname: str) -> Optional[LoadedDL]:
             abs_path = abs_path_for_dynamic_library(libname, handle)
             if abs_path is None:
                 raise RuntimeError(f"No expected symbol for {libname=!r}")
-            return LoadedDL(abs_path, False, handle._handle)
+            return LoadedDL(abs_path, False, handle._handle, "system-search")
     return None
 
 
@@ -193,7 +195,7 @@ def _work_around_known_bugs(libname: str, found_path: str) -> None:
                     ctypes.CDLL(dep_path, CDLL_MODE)
 
 
-def load_with_abs_path(libname: str, found_path: str) -> LoadedDL:
+def load_with_abs_path(libname: str, found_path: str, found_via: Optional[str] = None) -> LoadedDL:
     """Load a dynamic library from the given path.
 
     Args:
@@ -211,4 +213,4 @@ def load_with_abs_path(libname: str, found_path: str) -> LoadedDL:
         handle = _load_lib(libname, found_path)
     except OSError as e:
         raise RuntimeError(f"Failed to dlopen {found_path}: {e}") from e
-    return LoadedDL(found_path, False, handle._handle)
+    return LoadedDL(found_path, False, handle._handle, found_via)

cuda_pathfinder/cuda/pathfinder/_dynamic_libs/load_dl_windows.py

@@ -100,7 +100,10 @@ def abs_path_for_dynamic_library(libname: str, handle: ctypes.wintypes.HMODULE)
     return buffer.value
 
 
-def check_if_already_loaded_from_elsewhere(libname: str, have_abs_path: bool) -> Optional[LoadedDL]:
+def check_if_already_loaded_from_elsewhere(
+    libname: str,
+    have_abs_path: bool,
+) -> Optional[LoadedDL]:
     for dll_name in SUPPORTED_WINDOWS_DLLS.get(libname, ()):
         handle = kernel32.GetModuleHandleW(dll_name)
         if handle:
@@ -110,7 +113,7 @@ def check_if_already_loaded_from_elsewhere(libname: str, have_abs_path: bool) ->
                 # load_with_abs_path(). To make the side-effect more deterministic,
                 # activate it even if the library was already loaded from elsewhere.
                 add_dll_directory(abs_path)
-            return LoadedDL(abs_path, True, ctypes_handle_to_unsigned_int(handle))
+            return LoadedDL(abs_path, True, ctypes_handle_to_unsigned_int(handle), "already-loaded-from-elsewhere")
     return None
 
 
@@ -128,12 +131,12 @@ def load_with_system_search(libname: str) -> Optional[LoadedDL]:
         handle = kernel32.LoadLibraryExW(dll_name, None, 0)
         if handle:
             abs_path = abs_path_for_dynamic_library(libname, handle)
-            return LoadedDL(abs_path, False, ctypes_handle_to_unsigned_int(handle))
+            return LoadedDL(abs_path, False, ctypes_handle_to_unsigned_int(handle), "system-search")
 
     return None
 
 
-def load_with_abs_path(libname: str, found_path: str) -> LoadedDL:
+def load_with_abs_path(libname: str, found_path: str, found_via: Optional[str] = None) -> LoadedDL:
     """Load a dynamic library from the given path.
 
     Args:
@@ -156,4 +159,4 @@ def load_with_abs_path(libname: str, found_path: str) -> LoadedDL:
         error_code = ctypes.GetLastError()  # type: ignore[attr-defined]
         raise RuntimeError(f"Failed to load DLL at {found_path}: Windows error {error_code}")
 
-    return LoadedDL(found_path, False, ctypes_handle_to_unsigned_int(handle))
+    return LoadedDL(found_path, False, ctypes_handle_to_unsigned_int(handle), found_via)

cuda_pathfinder/cuda/pathfinder/_dynamic_libs/load_nvidia_dynamic_lib.py

@@ -26,8 +26,13 @@
 def _load_lib_no_cache(libname: str) -> LoadedDL:
     finder = _FindNvidiaDynamicLib(libname)
     abs_path = finder.try_site_packages()
+
     if abs_path is None:
         abs_path = finder.try_with_conda_prefix()
+        if abs_path is not None:
+            found_via = "conda"
+    else:
+        found_via = "site-packages"
 
     # If the library was already loaded by someone else, reproduce any OS-specific
     # side-effects we would have applied on a direct absolute-path load (e.g.,
@@ -49,8 +54,10 @@ def _load_lib_no_cache(libname: str) -> LoadedDL:
         abs_path = finder.try_with_cuda_home()
         if abs_path is None:
             finder.raise_not_found_error()
+        else:
+            found_via = "CUDA_HOME"
 
-    return load_with_abs_path(libname, abs_path)
+    return load_with_abs_path(libname, abs_path, found_via)
 
 
 @functools.cache

cuda_pathfinder/tests/child_load_nvidia_dynamic_lib_helper.py

@@ -43,6 +43,7 @@ def child_process_func(libname):
     if loaded_dl_fresh.was_already_loaded_from_elsewhere:
         raise RuntimeError("loaded_dl_fresh.was_already_loaded_from_elsewhere")
     validate_abs_path(loaded_dl_fresh.abs_path)
+    assert loaded_dl_fresh.foundvia is not None
 
     loaded_dl_from_cache = load_nvidia_dynamic_lib(libname)
     if loaded_dl_from_cache is not loaded_dl_fresh: