Python 3.15 __lazy_modules__ (auto-applied w/ flake8-lazy --apply=set)

Author: Avasam

newsfragments/5257.feature.rst

@@ -0,0 +1 @@
+Speed up setuptools imports on Python 3.15+ by adding ``__lazy_modules__`` -- by :user:`Avasam`

pyproject.toml

@@ -116,6 +116,7 @@ check = [
 
 	# Deprecated rules must now be selected by exact rule code
 	"ruff >= 0.13.0; sys_platform != 'cygwin'",
+	"flake8-lazy", # Until Ruff gains support for automatically inserting and validating __lazy_modules__
 ]
 
 cover = [

ruff.toml

@@ -5,6 +5,7 @@ exclude = [
 ]
 
 [lint]
+external=["LZY"]
 extend-select = [
 	# upstream
 

setuptools/__init__.py

@@ -7,6 +7,17 @@
 
 from __future__ import annotations
 
+__lazy_modules__ = {
+    "collections",
+    "collections.abc",
+    "functools",
+    f"{__spec__.parent}.depends",
+    f"{__spec__.parent}.dist",
+    f"{__spec__.parent}.extension",
+    f"{__spec__.parent}.version",
+    f"{__spec__.parent}.warnings",
+}
+
 import functools
 import os
 import sys

setuptools/_core_metadata.py

@@ -6,6 +6,22 @@
 
 from __future__ import annotations
 
+__lazy_modules__ = {
+    "distutils",
+    "distutils.util",
+    "email",
+    "email.message",
+    "packaging",
+    "packaging.markers",
+    "packaging.requirements",
+    "packaging.utils",
+    "packaging.version",
+    "tempfile",
+    "textwrap",
+    f"{__spec__.parent}._static",
+    f"{__spec__.parent}.warnings",
+}
+
 import os
 import stat
 import textwrap

setuptools/_discovery.py

@@ -1,3 +1,5 @@
+__lazy_modules__ = {"functools", "operator", "packaging", "packaging.requirements"}
+
 import functools
 import operator
 

setuptools/_entry_points.py

@@ -1,3 +1,13 @@
+__lazy_modules__ = {
+    "itertools",
+    "jaraco",
+    "jaraco.text",
+    "more_itertools",
+    "operator",
+    f"{__spec__.parent}._itertools",
+    f"{__spec__.parent}.errors",
+}
+
 import functools
 import itertools
 import operator
@@ -6,7 +16,7 @@
 from jaraco.text import yield_lines
 from more_itertools import consume
 
-from ._importlib import metadata
+from ._importlib import metadata  # noqa: LZY102
 from ._itertools import ensure_unique
 from .errors import OptionError
 

setuptools/_imp.py

@@ -3,6 +3,8 @@
 from the deprecated imp module.
 """
 
+__lazy_modules__ = {"importlib", "importlib.machinery", "importlib.util", "tokenize"}
+
 import importlib.machinery
 import importlib.util
 import os

setuptools/_importlib.py

@@ -1,3 +1,5 @@
+__lazy_modules__ = {"importlib"}
+
 from importlib import (
     metadata,  # noqa: F401
     resources,  # noqa: F401

setuptools/_itertools.py

@@ -1,3 +1,5 @@
+__lazy_modules__ = {"more_itertools"}
+
 from more_itertools import consume  # noqa: F401