Import errors with loo long entry in sys.path or PYTHONPATH in Windows

Bug report

Bug description:

Having too long entries in sys.path or PYTHONPATH in Windows will cause different errors in imports. This was first reported on #122170, where there is some useful discussion.

> $Env:PYTHONPATH="a" * 33000
> py -3.13
Exception ignored in running getpath:
Traceback (most recent call last):
  File "<frozen getpath>", line 668, in <module>
OSError: failed to make path absolute
Fatal Python error: error evaluating path
Python runtime state: core initialized

Current thread 0x00005a8c (most recent call first):
  <no Python frame>

>>> import sys
>>> sys.path.insert(0, "a" * 33000)
>>> import email
Traceback (most recent call last):
  File "<frozen importlib._bootstrap_external>", line 1512, in _path_importer_cache
KeyError: 'aaaaaaaaaaaaaaaaaaaaaaaa[...]aaaaaaaaaa'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<python-input-6>", line 1, in <module>
    import email
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1322, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 1262, in _find_spec
  File "<frozen importlib._bootstrap_external>", line 1555, in find_spec
  File "<frozen importlib._bootstrap_external>", line 1527, in _get_spec
  File "<frozen importlib._bootstrap_external>", line 1514, in _path_importer_cache
  File "<frozen importlib._bootstrap_external>", line 1490, in _path_hooks
  File "<frozen importlib._bootstrap_external>", line 1714, in path_hook_for_FileFinder
  File "<frozen importlib._bootstrap_external>", line 173, in _path_isdir
  File "<frozen importlib._bootstrap_external>", line 158, in _path_is_mode_type
  File "<frozen importlib._bootstrap_external>", line 152, in _path_stat
ValueError: stat: path too long for Windows

CPython versions tested on:

3.13, CPython main branch

Operating systems tested on:

Windows

Linked PRs

• gh-122389

Bắt đầu với các trường hợp tái hiện đường dẫn dài trong issue và kiểm tra các vị trí traceback của frozen getpath và importlib._bootstrap_external trên Windows. Xem lại issue #122170 và PR được liên kết gh-122389 để biết hướng triển khai hiện có. Được coi là hoàn tất khi các mục PYTHONPATH và sys.path dài không còn gây ra các lỗi khởi động hoặc import đã báo cáo.