Lazily import itertools

clin1234 · clin1234 · commit 97bde7505c8a · 2026-05-19T08:06:33.000-05:00
diff --git a/Lib/_pydecimal.py b/Lib/_pydecimal.py
@@ -6279,7 +6279,7 @@ def _group_lengths(grouping):
     #   (2) nonempty list of positive integers + [0]
     #   (3) list of positive integers + [locale.CHAR_MAX], or
 
-    from itertools import chain, repeat
+    lazy from itertools import chain, repeat
     if not grouping:
         return []
     elif grouping[-1] == 0 and len(grouping) >= 2:
diff --git a/Lib/_pylong.py b/Lib/_pylong.py
@@ -721,7 +721,7 @@ def inner(w):
         exp = compute_powers(w, 1, limit, need_hi=need_hi)
         assert exp.keys() == need
 
-    from itertools import chain
+    lazy from itertools import chain
     for need_hi in (False, True):
         for limit in (0, 1, 10, 100, 1_000, 10_000, 100_000):
             for w in chain(range(1, 100_000),
diff --git a/Lib/_pyrepl/_module_completer.py b/Lib/_pyrepl/_module_completer.py
@@ -11,7 +11,7 @@
 from io import StringIO
 from contextlib import contextmanager
 from dataclasses import dataclass
-from itertools import chain
+lazy from itertools import chain
 from tokenize import TokenInfo
 from .fancycompleter import safe_getattr
 
diff --git a/Lib/asyncio/tools.py b/Lib/asyncio/tools.py
@@ -1,7 +1,7 @@
 """Tools to analyze tasks running in asyncio programs."""
 
 from collections import defaultdict
-from itertools import count
+lazy from itertools import count
 from enum import Enum
 import sys
 from _remote_debugging import RemoteUnwinder, FrameInfo
diff --git a/Lib/calendar.py b/Lib/calendar.py
@@ -9,7 +9,7 @@
 import datetime
 from enum import IntEnum, global_enum
 import locale as _locale
-from itertools import repeat
+lazy from itertools import repeat
 
 __all__ = ["IllegalMonthError", "IllegalWeekdayError", "setfirstweekday",
            "firstweekday", "isleap", "leapdays", "weekday", "monthrange",
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
@@ -34,9 +34,9 @@
 
 lazy from copy import copy as _copy
 lazy from heapq import nlargest as _nlargest
-from itertools import chain as _chain
-from itertools import repeat as _repeat
-from itertools import starmap as _starmap
+lazy from itertools import chain as _chain
+lazy from itertools import repeat as _repeat
+lazy from itertools import starmap as _starmap
 from keyword import iskeyword as _iskeyword
 from operator import eq as _eq
 from operator import itemgetter as _itemgetter
diff --git a/Lib/concurrent/futures/_base.py b/Lib/concurrent/futures/_base.py
@@ -9,7 +9,7 @@
 import time
 import types
 import weakref
-from itertools import islice
+lazy from itertools import islice
 
 FIRST_COMPLETED = 'FIRST_COMPLETED'
 FIRST_EXCEPTION = 'FIRST_EXCEPTION'
diff --git a/Lib/ctypes/macholib/dyld.py b/Lib/ctypes/macholib/dyld.py
@@ -5,7 +5,7 @@
 import os
 from ctypes.macholib.framework import framework_info
 from ctypes.macholib.dylib import dylib_info
-from itertools import *
+lazy from itertools import *
 try:
     from _ctypes import _dyld_shared_cache_contains_path
 except ImportError:
diff --git a/Lib/filecmp.py b/Lib/filecmp.py
@@ -12,7 +12,7 @@
 
 import os
 import stat
-from itertools import filterfalse
+lazy from itertools import filterfalse
 from types import GenericAlias
 
 __all__ = ['clear_cache', 'cmp', 'dircmp', 'cmpfiles', 'DEFAULT_IGNORES']
diff --git a/Lib/idlelib/idle_test/test_sidebar.py b/Lib/idlelib/idle_test/test_sidebar.py
@@ -2,7 +2,7 @@
 from textwrap import dedent
 import sys
 
-from itertools import chain
+lazy from itertools import chain
 import unittest
 import unittest.mock
 from test.support import requires, swap_attr
diff --git a/Lib/importlib/metadata/__init__.py b/Lib/importlib/metadata/__init__.py
@@ -26,7 +26,7 @@
 from contextlib import suppress
 from importlib import import_module
 from importlib.abc import MetaPathFinder
-from itertools import starmap
+lazy from itertools import starmap
 from typing import Any
 
 from . import _meta
diff --git a/Lib/importlib/metadata/_itertools.py b/Lib/importlib/metadata/_itertools.py
@@ -1,5 +1,5 @@
 from collections import defaultdict, deque
-from itertools import filterfalse
+lazy from itertools import filterfalse
 
 
 def unique_everseen(iterable, key=None):
@@ -99,7 +99,7 @@ class bucket:
     If you specify a *validator* function, selected buckets will instead be
     checked against it.
 
-        >>> from itertools import count
+        >>> lazy from itertools import count
         >>> it = count(1, 2)  # Infinite sequence of odd numbers
         >>> key = lambda x: x % 10  # Bucket by last digit
         >>> validator = lambda x: x in {1, 3, 5, 7, 9}  # Odd digits only
diff --git a/Lib/pathlib/__init__.py b/Lib/pathlib/__init__.py
@@ -12,7 +12,7 @@
 import posixpath
 import sys
 from errno import *
-from itertools import chain
+lazy from itertools import chain
 from stat import (
     S_IMODE, S_ISDIR, S_ISREG, S_ISLNK, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO,
 )
diff --git a/Lib/pickle.py b/Lib/pickle.py
@@ -25,7 +25,7 @@
 from types import FunctionType
 from copyreg import dispatch_table
 from copyreg import _extension_registry, _inverted_registry, _extension_cache
-from itertools import batched
+lazy from itertools import batched
 from functools import partial
 import sys
 from sys import maxsize
diff --git a/Lib/profiling/sampling/jsonl_collector.py b/Lib/profiling/sampling/jsonl_collector.py
@@ -71,7 +71,7 @@
 from collections import Counter
 import json
 import uuid
-from itertools import batched
+lazy from itertools import batched
 
 from .constants import PROFILING_MODE_NAMES
 from .collector import normalize_location
diff --git a/Lib/random.py b/Lib/random.py
@@ -57,7 +57,7 @@
 from os import urandom as _urandom
 from _collections_abc import Sequence as _Sequence
 from operator import index as _index
-from itertools import accumulate as _accumulate, repeat as _repeat
+lazy from itertools import accumulate as _accumulate, repeat as _repeat
 from bisect import bisect as _bisect
 import os as _os
 import _random
diff --git a/Lib/reprlib.py b/Lib/reprlib.py
@@ -3,7 +3,7 @@
 __all__ = ["Repr", "repr", "recursive_repr"]
 
 import builtins
-from itertools import islice
+lazy from itertools import islice
 from _thread import get_ident
 
 def recursive_repr(fillvalue='...'):
diff --git a/Lib/sched.py b/Lib/sched.py
@@ -26,7 +26,7 @@
 import time
 import heapq
 from collections import namedtuple
-from itertools import count
+lazy from itertools import count
 import threading
 from time import monotonic as _time
 
diff --git a/Lib/statistics.py b/Lib/statistics.py
@@ -136,7 +136,7 @@
 
 from fractions import Fraction
 from decimal import Decimal
-from itertools import compress, count, groupby, repeat
+lazy from itertools import compress, count, groupby, repeat
 from bisect import bisect_left, bisect_right
 from math import hypot, sqrt, fabs, exp, erfc, tau, log, fsum, sumprod
 from math import isfinite, isinf, pi, cos, sin, tan, cosh, asin, atan, acos
diff --git a/Lib/test/seq_tests.py b/Lib/test/seq_tests.py
@@ -82,7 +82,7 @@ def __iter__(self):
     def __next__(self):
         raise StopIteration
 
-from itertools import chain
+lazy from itertools import chain
 def itermulti(seqn):
     'Test multiple tiers of iterators'
     return chain(map(lambda x:x, iterfunc(IterGen(Sequence(seqn)))))
diff --git a/Lib/test/test_asyncio/test_sock_lowlevel.py b/Lib/test/test_asyncio/test_sock_lowlevel.py
@@ -4,7 +4,7 @@
 import unittest
 
 from asyncio import proactor_events
-from itertools import cycle, islice
+lazy from itertools import cycle, islice
 from unittest.mock import Mock
 from test.test_asyncio import utils as test_utils
 from test import support
diff --git a/Lib/test/test_bdb.py b/Lib/test/test_bdb.py
@@ -56,7 +56,7 @@
 import importlib
 import linecache
 from contextlib import contextmanager
-from itertools import islice, repeat
+lazy from itertools import islice, repeat
 from test.support import import_helper
 from test.support import os_helper
 from test.support import patch_list
diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
@@ -18,7 +18,7 @@
 from test import support
 from test.support import os_helper
 import inspect
-from itertools import permutations, product
+lazy from itertools import permutations, product
 from random import randrange, sample, choice
 import warnings
 import sys, array, io, os
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
@@ -26,7 +26,7 @@
 from contextlib import ExitStack
 from functools import partial
 from inspect import CO_COROUTINE
-from itertools import product
+lazy from itertools import product
 from textwrap import dedent
 from types import AsyncGeneratorType, FunctionType, CellType
 from operator import neg
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
@@ -8,7 +8,7 @@
 import operator
 import pickle
 from random import choice, randrange
-from itertools import product, chain, combinations
+lazy from itertools import product, chain, combinations
 import string
 import sys
 from test import support
diff --git a/Lib/test/test_csv.py b/Lib/test/test_csv.py
@@ -12,7 +12,7 @@
 from test import support
 from test.support import cpython_only, import_helper, check_disallow_instantiation
 from test.support.import_helper import ensure_lazy_imports
-from itertools import permutations
+lazy from itertools import permutations
 from textwrap import dedent
 from collections import OrderedDict
 
diff --git a/Lib/test/test_ctypes/test_numbers.py b/Lib/test/test_ctypes/test_numbers.py
@@ -3,7 +3,7 @@
 import struct
 import sys
 import unittest
-from itertools import combinations
+lazy from itertools import combinations
 from operator import truth
 from ctypes import (byref, sizeof, alignment,
                     c_char, c_byte, c_ubyte, c_short, c_ushort, c_int, c_uint,
diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
@@ -9,7 +9,7 @@
 import textwrap
 
 from io import StringIO, BytesIO
-from itertools import chain
+lazy from itertools import chain
 from random import choice
 from threading import Thread
 from unittest.mock import patch
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
@@ -8,7 +8,7 @@
 import weakref
 import errno
 from codecs import BOM_UTF8
-from itertools import product
+lazy from itertools import product
 from textwrap import dedent
 
 from test.support import (captured_stderr, check_impl_detail,
diff --git a/Lib/test/test_free_threading/test_itertools.py b/Lib/test/test_free_threading/test_itertools.py
@@ -1,5 +1,5 @@
 import unittest
-from itertools import accumulate, batched, chain, combinations_with_replacement, cycle, permutations, zip_longest
+lazy from itertools import accumulate, batched, chain, combinations_with_replacement, cycle, permutations, zip_longest
 from test.support import threading_helper
 
 
diff --git a/Lib/test/test_free_threading/test_itertools_combinatoric.py b/Lib/test/test_free_threading/test_itertools_combinatoric.py
@@ -1,6 +1,6 @@
 import unittest
 from threading import Thread, Barrier
-from itertools import combinations, product
+lazy from itertools import combinations, product
 from test.support import threading_helper
 
 
diff --git a/Lib/test/test_free_threading/test_str.py b/Lib/test/test_free_threading/test_str.py
@@ -2,7 +2,7 @@
 import threading
 import unittest
 
-from itertools import cycle
+lazy from itertools import cycle
 from threading import Barrier, Event, Thread
 from unittest import TestCase
 
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
@@ -4,7 +4,7 @@
 import collections
 import collections.abc
 import copy
-from itertools import permutations
+lazy from itertools import permutations
 import pickle
 from random import choice
 import re
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
@@ -1655,7 +1655,7 @@ def b():
 Thanks to itertools.tee, it is now clear "how to get the internal uses of
 m235 to share a single generator".
 
->>> from itertools import tee
+>>> lazy from itertools import tee
 >>> def m235():
 ...     def _m235():
 ...         yield 1
diff --git a/Lib/test/test_genericalias.py b/Lib/test/test_genericalias.py
@@ -25,7 +25,7 @@
 from difflib import SequenceMatcher
 from filecmp import dircmp
 from fileinput import FileInput
-from itertools import chain
+lazy from itertools import chain
 from http.cookies import Morsel
 try:
     from multiprocessing.managers import ValueProxy, DictProxy, ListProxy
diff --git a/Lib/test/test_heapq.py b/Lib/test/test_heapq.py
@@ -497,7 +497,7 @@ def __iter__(self):
     def __next__(self):
         raise StopIteration
 
-from itertools import chain
+lazy from itertools import chain
 def L(seqn):
     'Test multiple tiers of iterators'
     return chain(map(lambda x:x, R(Ig(G(seqn)))))
diff --git a/Lib/test/test_io/test_bufferedio.py b/Lib/test/test_io/test_bufferedio.py
@@ -8,7 +8,7 @@
 import warnings
 import weakref
 from collections import deque, UserList
-from itertools import cycle, count
+lazy from itertools import cycle, count
 from test import support
 from test.support import check_sanitizer, os_helper, threading_helper
 from .utils import byteslike, CTestCase, PyTestCase
diff --git a/Lib/test/test_iterlen.py b/Lib/test/test_iterlen.py
@@ -42,7 +42,7 @@
 """
 
 import unittest
-from itertools import repeat
+lazy from itertools import repeat
 from collections import deque
 from operator import length_hint
 
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
@@ -3,7 +3,7 @@
 import itertools
 from test import support
 from test.support import threading_helper, script_helper
-from itertools import *
+lazy from itertools import *
 import weakref
 from decimal import Decimal
 from fractions import Fraction
@@ -1514,7 +1514,7 @@ def test_pairwise_result_gc(self):
 
     @support.cpython_only
     def test_immutable_types(self):
-        from itertools import _grouper, _tee, _tee_dataobject
+        lazy from itertools import _grouper, _tee, _tee_dataobject
         dataset = (
             accumulate,
             batched,
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
@@ -1503,7 +1503,7 @@ def run(func, *args):
     def test_sumprod_extended_precision_accuracy(self):
         import operator
         from fractions import Fraction
-        from itertools import starmap
+        lazy from itertools import starmap
         from collections import namedtuple
         from math import log2, exp2, fabs
         from random import choices, uniform, shuffle
diff --git a/Lib/test/test_memoryview.py b/Lib/test/test_memoryview.py
@@ -15,7 +15,7 @@
 import pickle
 import struct
 
-from itertools import product
+lazy from itertools import product
 from test import support
 from test.support import import_helper, threading_helper
 
diff --git a/Lib/test/test_peepholer.py b/Lib/test/test_peepholer.py
@@ -1,7 +1,7 @@
 import ast
 import dis
 import gc
-from itertools import combinations, product
+lazy from itertools import combinations, product
 import opcode
 import sys
 import textwrap
diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py
diff --git a/Lib/test/test_sort.py b/Lib/test/test_sort.py
diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
diff --git a/Lib/test/test_tuple.py b/Lib/test/test_tuple.py
diff --git a/Lib/test/test_unittest/test_assertions.py b/Lib/test/test_unittest/test_assertions.py
diff --git a/Lib/test/test_uuid.py b/Lib/test/test_uuid.py
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
diff --git a/Lib/test/test_zipfile/_path/_itertools.py b/Lib/test/test_zipfile/_path/_itertools.py
diff --git a/Lib/threading.py b/Lib/threading.py
diff --git a/Tools/c-analyzer/distutils/_msvccompiler.py b/Tools/c-analyzer/distutils/_msvccompiler.py
diff --git a/Tools/msi/csv_to_wxs.py b/Tools/msi/csv_to_wxs.py
