jupyter-server fails to find anyio>=2.0.2

[NF6X (Mark J. Blair)]

When I try to use jupyter-lab-3.8 from py38-jupyterlab @3.0.4_0, it fails with:

> pkg_resources.DistributionNotFound: The 'anyio>=2.0.2' distribution was not found and is required by jupyter-server

despite py38-anyio @2.0.2_0 being installed.

[NF6X (Mark J. Blair)]

The full traceback printed is:

Traceback (most recent call last):
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 567, in _build_master
    ws.require(__requires__)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 884, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 775, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (anyio 0.0.0 (/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages), Requirement.parse('anyio>=2.0.2'), {'jupyter-server'})

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/local/bin/jupyter-lab-3.8", line 33, in <module>
    sys.exit(load_entry_point('jupyterlab==3.0.4', 'console_scripts', 'jupyter-lab')())
  File "/opt/local/bin/jupyter-lab-3.8", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/importlib/metadata.py", line 77, in load
    module = import_module(match.group('module'))
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab/__init__.py", line 7, in <module>
    from .labapp import LabApp
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab/labapp.py", line 16, in <module>
    from jupyterlab_server import slugify, WORKSPACE_EXTENSION
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab_server/__init__.py", line 4, in <module>
    from .app import LabServerApp
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab_server/app.py", line 16, in <module>
    from .handlers import add_handlers, LabConfig
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab_server/handlers.py", line 24, in <module>
    from .translations_handler import TranslationsHandler
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab_server/translations_handler.py", line 16, in <module>
    from .translation_utils import get_language_pack, get_language_packs, is_valid_locale, translator
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/jupyterlab_server/translation_utils.py", line 15, in <module>
    import pkg_resources
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 3239, in <module>
    def _initialize_master_working_set():
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 3222, in _call_aside
    f(*args, **kwargs)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 3251, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 569, in _build_master
    return cls._build_from_requirements(__requires__)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 582, in _build_from_requirements
    dists = ws.resolve(reqs, Environment())
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pkg_resources/__init__.py", line 770, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'anyio>=2.0.2' distribution was not found and is required by jupyter-server

[reneeotten (Renee Otten)]

In d1332239664a694c18858a0ab447f9f21b4f27fd/macports-ports (master):

py-anyio: fix to set correct version

Closes: #62066