pip crashes on python 3.6.1 with "cannot import name 'NoReturn'"

[njsmith]

Description

From our CI logs:

[...]
Successfully installed pip-21.1 setuptools-56.0.0 wheel-0.36.2
+python -m pip --version
Traceback (most recent call last):
  File "/opt/python/3.6.1/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/opt/python/3.6.1/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/travis/virtualenv/python3.6.1/lib/python3.6/site-packages/pip/__main__.py", line 29, in <module>
    from pip._internal.cli.main import main as _main
  File "/home/travis/virtualenv/python3.6.1/lib/python3.6/site-packages/pip/_internal/cli/main.py", line 9, in <module>
    from pip._internal.cli.autocompletion import autocomplete
  File "/home/travis/virtualenv/python3.6.1/lib/python3.6/site-packages/pip/_internal/cli/autocompletion.py", line 10, in <module>
    from pip._internal.cli.main_parser import create_main_parser
  File "/home/travis/virtualenv/python3.6.1/lib/python3.6/site-packages/pip/_internal/cli/main_parser.py", line 8, in <module>
    from pip._internal.cli import cmdoptions
  File "/home/travis/virtualenv/python3.6.1/lib/python3.6/site-packages/pip/_internal/cli/cmdoptions.py", line 30, in <module>
    from pip._internal.utils.hashes import STRONG_HASHES
  File "/home/travis/virtualenv/python3.6.1/lib/python3.6/site-packages/pip/_internal/utils/hashes.py", line 2, in <module>
    from typing import TYPE_CHECKING, BinaryIO, Dict, Iterator, List, NoReturn
ImportError: cannot import name 'NoReturn'

Apparently typing.NoReturn was only added in 3.6.2.

I guess we'll probably just stop testing on 3.6.1, but here's a heads up anyway.

Expected behavior

No response

pip version

21.1

Python version

3.6.1

OS

linux

How to Reproduce

see above.

Output

see above.

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[pfmoore]

Thanks. This was already reported in #9831. Technically, we only support the latest patch release of any supported CPython version, but there's a fix in #9835 which has been merged. We're currently discussing a 21.1.1 release.

[pfmoore]

I'll close this as a duplicate.

[njsmith]

Ah whoops, I only checked open issues :-)