Use functools.lru_cache to cache supported tags for wheels.

This is a suggestion by @abravalheri for my PR.
https://github.com/pypa/setuptools/pull/3805#issuecomment-1434361907

1 files changed, 9 insertions, 8 deletions

diff --git a/setuptools/wheel.py b/setuptools/wheel.py
index aab7ed05..ff29e2fb 100644
--- a/setuptools/wheel.py
+++ b/setuptools/wheel.py
@@ -2,6 +2,7 @@
 
 import email
 import itertools
+import functools
 import os
 import posixpath
 import re
@@ -27,7 +28,13 @@ WHEEL_NAME = re.compile(
 NAMESPACE_PACKAGE_INIT = \
     "__import__('pkg_resources').declare_namespace(__name__)\n"
 
-_supported_tags = None
+
+@functools.lru_cache(maxsize=None)
+def _get_supported_tags():
+    # We calculate the supported tags only once, otherwise calling
+    # this method on thousands of wheels takes seconds instead of
+    # milliseconds.
+    return set((t.interpreter, t.abi, t.platform) for t in sys_tags())
 
 
 def unpack(src_dir, dst_dir):
@@ -85,13 +92,7 @@ class Wheel:
 
     def is_compatible(self):
         '''Is the wheel compatible with the current platform?'''
-        global _supported_tags
-        if _supported_tags is None:
-            # We calculate the supported tags only once, otherwise calling
-            # this method on thousands of wheels takes seconds instead of
-            # milliseconds.
-            _supported_tags = set(
-                (t.interpreter, t.abi, t.platform) for t in sys_tags())
+        _supported_tags = _get_supported_tags()
         return next((True for t in self.tags() if t in _supported_tags), False)
 
     def egg_name(self):