Deprecation warning for setuptools.command._install

setuptools/command/install.py

@@ -4,7 +4,7 @@
 import inspect
 import platform
 from collections.abc import Callable
-from typing import Any, ClassVar, cast
+from typing import TYPE_CHECKING, Any, ClassVar, cast
 
 import setuptools
 
@@ -15,9 +15,22 @@
 import distutils.command.install as orig
 from distutils.errors import DistutilsArgError
 
-# Prior to numpy 1.9, NumPy relies on the '_install' name, so provide it for
-# now. See https://github.com/pypa/setuptools/issues/199/
-_install = orig.install
+if TYPE_CHECKING:
+    # This is only used for a type-cast, don't import at runtime or it'll cause deprecation warnings
+    from .easy_install import easy_install as easy_install_cls
+else:
+    easy_install_cls = None
+
+
+def __getattr__(name: str):  # pragma: no cover
+    if name == "_install":
+        SetuptoolsDeprecationWarning.emit(
+            "`setuptools.command._install` was an internal implementation detail "
+            + "that was left in for numpy<1.9 support.",
+            due_date=(2025, 5, 2),  # Originally added on 2024-11-01
+        )
+        return orig.install
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
 
 
 class install(orig.install):
@@ -131,7 +144,9 @@ def _called_from_setup(run_frame):
         return False
 
     def do_egg_install(self) -> None:
-        easy_install = self.distribution.get_command_class('easy_install')
+        easy_install = cast(
+            type[easy_install_cls], self.distribution.get_command_class('easy_install')
+        )
 
         cmd = easy_install(
             self.distribution,