typing-extensions shouldn't break black installation on Python 3.8 and 3.9

[MaybeThisIsRu]

Describe the bug

When pipenv tries to lock dependencies, the following sub-dependency error arises:

✘ Locking Failed! 
[ResolutionFailure]:   File "/home/ru/.local/lib/python3.9/site-packages/pipenv/resolver.py", line 741, in _main
[ResolutionFailure]:       resolve_packages(pre, clear, verbose, system, write, requirements_dir, packages, dev)
[ResolutionFailure]:   File "/home/ru/.local/lib/python3.9/site-packages/pipenv/resolver.py", line 702, in resolve_packages
[ResolutionFailure]:       results, resolver = resolve(
[ResolutionFailure]:   File "/home/ru/.local/lib/python3.9/site-packages/pipenv/resolver.py", line 684, in resolve
[ResolutionFailure]:       return resolve_deps(
[ResolutionFailure]:   File "/home/ru/.local/lib/python3.9/site-packages/pipenv/utils.py", line 1397, in resolve_deps
[ResolutionFailure]:       results, hashes, markers_lookup, resolver, skipped = actually_resolve_deps(
[ResolutionFailure]:   File "/home/ru/.local/lib/python3.9/site-packages/pipenv/utils.py", line 1110, in actually_resolve_deps
[ResolutionFailure]:       resolver.resolve()
[ResolutionFailure]:   File "/home/ru/.local/lib/python3.9/site-packages/pipenv/utils.py", line 835, in resolve
[ResolutionFailure]:       raise ResolutionFailure(message=str(e))
[pipenv.exceptions.ResolutionFailure]: Warning: Your dependencies could not be resolved. You likely have a mismatch in your sub-dependencies.
  First try clearing your dependency cache with $ pipenv lock --clear, then try the original command again.
 Alternatively, you can use $ pipenv install --skip-lock to bypass this mechanism, then run $ pipenv graph to inspect the situation.
  Hint: try $ pipenv lock --pre if it is a pre-release dependency.
ERROR: Could not find a version that matches typing-extensions>=3.10.0.0,~=3.7.4.2 (from black==21.9b0->-r /tmp/pipenvwy0b124trequirements/pipenv-jp_9ytoa-constraints.txt (line 5))
Tried: 3.6.2, 3.6.2, 3.6.2.1, 3.6.2.1, 3.6.5, 3.6.5, 3.6.6, 3.6.6, 3.7.2, 3.7.2, 3.7.4, 3.7.4, 3.7.4.1, 3.7.4.1, 3.7.4.2, 3.7.4.2, 3.7.4.3, 3.7.4.3, 3.10.0.0, 3.10.0.0, 3.10.0.1, 3.10.0.1, 3.10.0.2, 3.10.0.2
There are incompatible versions in the resolved dependencies:
  typing-extensions>=3.10.0.0 (from black==21.9b0->-r /tmp/pipenvwy0b124trequirements/pipenv-jp_9ytoa-constraints.txt (line 5))
  typing-extensions~=3.7.4.2 (from statham-schema==0.13.4->toshling==0.0.4->-r /tmp/pipenvwy0b124trequirements/pipenv-jp_9ytoa-constraints.txt (line 6))

To Reproduce

Ensure you have pipenv.

• mkdir sample-project && cd sample-project
• pipenv --python 3.9
• pipenv install toshling
• pipenv install --pre --dev black
• pipenv fails to lock.

Expected behavior

• pipenv locks successfully.

Environment (please complete the following information):

• Pop!_OS 20.04 LTS
• Python 3.9.7
• black 21.90b
• asdf v0.8.1-a1ef92a
• pipenv, version 2021.5.29

Additional context:

Looks like black recently had a PR #2460 for Python 3.10, which removes the earlier work on #1873. This likely leaves Python 3.8 and 3.9 in a pickle.

[MaybeThisIsRu]

Running black==21.7b0 for Python 3.9.7 at the moment, thanks to #2465 (comment). This works fine.

[JelleZijlstra]

Seems like the issue is that we require 3.10.0.0 and statham-schema requires 3.7.4.2. Could you instead ask the other library to update their dependency?

[ichard26]

FYI unless we want to drop the usage of TypeGuard in the codebase we can't really do anything as typing-extensions 3.10.0.0 is the first version to contain it. PR #2460 isn't related here as typing-extensions was already re-required for 3.8 / 3.9 via the Jupyter PR #2357.

[ichard26]

Given there hasn't been any further activity asking for us to undo our modern typing-extension requirements I'll be closing this issue as it has nothing actionable as of right now. I'll be happy to reopen if a stronger case is made to why we should remove the pin. Thanks for chiming in @hirusi!