gh-117865: Speedup import of inspect module (#144756)

Co-authored-by: Alex Waygood <alex.waygood@gmail.com>

Lib/inspect.py

@@ -153,9 +153,9 @@
 import itertools
 import linecache
 import os
-import re
+lazy import re
 import sys
-import tokenize
+lazy import tokenize
 import token
 import types
 import functools
@@ -163,9 +163,9 @@
 from keyword import iskeyword
 from operator import attrgetter
 from collections import namedtuple, OrderedDict
-from weakref import ref as make_weakref
+from _weakref import ref as make_weakref
 
-# Create constants for the compiler flags in Include/code.h
+# Create constants for the compiler flags in Include/cpython/code.h
 # We try to get them from dis to avoid duplication
 mod_dict = globals()
 for k, v in dis.COMPILER_FLAG_NAMES.items():

Lib/test/test_inspect/test_inspect.py

@@ -173,6 +173,15 @@ def __get__(self, instance, owner):
         return self.func.__get__(instance, owner)
 
 
+class TestImportTime(unittest.TestCase):
+
+    @cpython_only
+    def test_lazy_import(self):
+        import_helper.ensure_lazy_imports(
+            "inspect", {"re", "tokenize"}
+        )
+
+
 class TestPredicates(IsTestBase):
 
     def test_excluding_predicates(self):

Misc/NEWS.d/next/Library/2026-02-12-17-56-17.gh-issue-117865.jE1ema.rst

@@ -0,0 +1 @@
+Reduce the import time of :mod:`inspect` module by ~20%.