GH-129064: deprecate sysconfig.expand_makefile_vars

Lib/sysconfig/__init__.py

@@ -716,6 +716,15 @@ def expand_makefile_vars(s, vars):
     variable expansions; if 'vars' is the output of 'parse_makefile()',
     you're fine.  Returns a variable-expanded version of 's'.
     """
+
+    import warnings
+    warnings.warn(
+        'sysconfig.expand_makefile_vars is deprecated and will be removed in '
+        'Python 3.16. Use sysconfig.get_paths(vars=...) instead.',
+        DeprecationWarning,
+        stacklevel=2,
+    )
+
     import re
 
     _findvar1_rx = r"\$\(([A-Za-z][A-Za-z0-9_]*)\)"

Lib/test/test_sysconfig.py

@@ -711,5 +711,24 @@ def test_parse_makefile(self):
         })
 
 
+class DeprecationTests(unittest.TestCase):
+    def deprecated(self, removal_version, deprecation_msg=None, attribute_msg=None):
+        if sys.version_info >= removal_version:
+            return self.assertRaises(AttributeError, msg=attribute_msg)
+        else:
+            return self.assertWarns(DeprecationWarning, msg=deprecation_msg)
+
+    def test_expand_makefile_vars(self):
+        with self.deprecated(
+            removal_version=(3, 16),
+            deprecation_msg=(
+                'sysconfig.expand_makefile_vars is deprecated and will be removed in '
+                'Python 3.16. Use sysconfig.get_paths(vars=...) instead.',
+            ),
+            attribute_msg="module 'sysconfig' has no attribute 'expand_makefile_vars'",
+        ):
+            sysconfig.expand_makefile_vars('', {})
+
+
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Library/2025-01-20-16-02-38.gh-issue-129064.JXasgJ.rst

@@ -0,0 +1,2 @@
+Deprecate :func:`sysconfig.expand_makefile_vars`, in favor of using
+:func:`sysconfig.get_paths` with the ``vars`` argument.