[fbsync] Fix for windows and python 3.8 call to add_dll_directory (#6742

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Reviewed By: NicolasHug

Differential Revision: D40427472

fbshipit-source-id: bbcd971213459005e03ea2b0f9e7ff797b7eb228

torchvision/extension.py

@@ -21,12 +21,16 @@ def _has_ops():
     # To find cuda related dlls we need to make sure the
     # conda environment/bin path is configured Please take a look:
     # https://stackoverflow.com/questions/59330863/cant-import-dll-module-in-python
+    # Please note: if some path can't be added using add_dll_directory we simply ignore this path
     if os.name == "nt" and sys.version_info >= (3, 8) and sys.version_info < (3, 9):
         env_path = os.environ["PATH"]
         path_arr = env_path.split(";")
         for path in path_arr:
             if os.path.exists(path):
-                os.add_dll_directory(path)  # type: ignore[attr-defined]
+                try:
+                    os.add_dll_directory(path)  # type: ignore[attr-defined]
+                except Exception:
+                    pass
 
     lib_path = _get_extension_path("_C")
     torch.ops.load_library(lib_path)