Use add_dll_directory as a context manager

pytensor/link/c/cmodule.py

@@ -21,7 +21,7 @@ import textwrap
 import time
 import warnings
 from collections.abc import Callable
-from functools import cache
+from contextlib import AbstractContextManager, nullcontext
 from io import BytesIO, StringIO
 from typing import TYPE_CHECKING, Protocol, cast
 
@@ -272,15 +272,15 @@ def _get_ext_suffix():
     return dist_suffix
 
 
-@cache  # See explanation in docstring.
-def add_gcc_dll_directory() -> None:
+def add_gcc_dll_directory() -> AbstractContextManager[None]:
     """On Windows, detect and add the location of gcc to the DLL search directory.
 
     On non-Windows platforms this is a noop.
 
-    The @cache decorator ensures that this function only executes once to avoid
-    redundant entries. See <https://github.com/pymc-devs/pytensor/pull/678>.
+    Returns a context manager to be used with `with`. The entry is removed when the
+    context manager is closed. See <https://github.com/pymc-devs/pytensor/pull/678>.
     """
+    cm: AbstractContextManager[None] = nullcontext()
     if (sys.platform == "win32") & (hasattr(os, "add_dll_directory")):
         gcc_path = shutil.which("gcc")
         if gcc_path is not None:
@@ -288,7 +288,8 @@ def add_gcc_dll_directory() -> None:
             # the ignore[attr-defined] on non-Windows platforms.
             # For Windows we need ignore[unused-ignore] since the ignore
             # is unnecessary with that platform.
-            os.add_dll_directory(os.path.dirname(gcc_path))  # type: ignore[attr-defined,unused-ignore]
+            cm = os.add_dll_directory(os.path.dirname(gcc_path))  # type: ignore[attr-defined,unused-ignore]
+    return cm
 
 
 def dlimport(fullpath, suffix=None):
@@ -340,7 +341,7 @@ def dlimport(fullpath, suffix=None):
     _logger.debug(f"module_name {module_name}")
 
     sys.path[0:0] = [workdir]  # insert workdir at beginning (temporarily)
-    add_gcc_dll_directory()
+    with add_gcc_dll_directory():
         global import_time
         try:
             importlib.invalidate_caches()