[BUG] Setuptools crashes when implementing find_distributions in a custom Finder in python 3.8 #3319
Description
setuptools version
setuptools==62.2.0
Python version
3.8
OS
Ubuntu 20.04
Additional environment information
No response
Description
When implementing find_distributions on a custom Finder, setuptools crashes because it expects the returned PathDistribution instances to have attributes only present in its vendored importlib_metadata but not in python 3.8's importlib.metadata.
See https://github.com/konstin/setuptools-reproducer:
virtualenv -p 3.8 .venv
.venv/bin/pip install -r requirements.txt # pinned versions of setuptools and virtualenv
.venv/bin/python main.pyimport sys
from importlib.abc import MetaPathFinder
from importlib.machinery import PathFinder, ModuleSpec
from importlib.metadata import DistributionFinder, PathDistribution
from importlib.util import spec_from_file_location
from pathlib import Path
from typing import Iterable, Optional
class CustomFinder(PathFinder, MetaPathFinder):
"""As example, we load tqdm from a custom location"""
tqdm_folder = Path(__file__).parent.joinpath("tqdm_folder")
def find_spec(self, fullname, path=None, target=None) -> Optional[ModuleSpec]:
if fullname == "tqdm":
init_py = self.tqdm_folder.joinpath("tqdm").joinpath("__init__.py")
return spec_from_file_location(fullname, init_py)
def find_distributions(
self, context: DistributionFinder.Context = ...
) -> Iterable[PathDistribution]:
dist_info = self.tqdm_folder.joinpath("tqdm_folder").joinpath(
"tqdm-4.64.0.dist-info"
)
# Here, we return a normal python3.8 importlib.metadata.PathDistribution
return iter([PathDistribution(dist_info)])
sys.meta_path.append(CustomFinder())
# this works - we successfully made tqdm importable
# noinspection PyUnresolvedReferences
import tqdm
print(tqdm.__version__)
# this doesn't
# noinspection PyUnresolvedReferences
import virtualenv
print(virtualenv.__version__)Latest main is also affected
Expected behavior
setuptools accepts importlib.metadata.PathDistribution instances.
How to Reproduce
See https://github.com/konstin/setuptools-reproducer reproduce.sh
Output
Traceback (most recent call last):
File "main.py", line 39, in <module>
import virtualenv
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/__init__.py", line 3, in <module>
from .run import cli_run, session_via_cli
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/run/__init__.py", line 14, in <module>
from .plugin.creators import CreatorSelector
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/run/plugin/creators.py", line 6, in <module>
from virtualenv.create.via_global_ref.builtin.builtin_way import VirtualenvBuiltin
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/create/via_global_ref/builtin/builtin_way.py", line 7, in <module>
from virtualenv.create.creator import Creator
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/create/creator.py", line 15, in <module>
from virtualenv.discovery.cached_py_info import LogCmd
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/discovery/cached_py_info.py", line 23, in <module>
_CACHE[Path(sys.executable)] = PythonInfo()
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/discovery/py_info.py", line 86, in __init__
self.distutils_install = {u(k): u(v) for k, v in self._distutils_install().items()}
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/virtualenv/discovery/py_info.py", line 152, in _distutils_install
d = dist.Distribution({"script_args": "--no-user-cfg"}) # conf files not parsed so they do not hijack paths
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/setuptools/dist.py", line 470, in __init__
for ep in metadata.entry_points(group='distutils.setup_keywords'):
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/setuptools/_vendor/importlib_metadata/__init__.py", line 999, in entry_points
return SelectableGroups.load(eps).select(**params)
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/setuptools/_vendor/importlib_metadata/__init__.py", line 449, in load
ordered = sorted(eps, key=by_group)
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/setuptools/_vendor/importlib_metadata/__init__.py", line 996, in <genexpr>
eps = itertools.chain.from_iterable(
File "/home/konsti/setuptools-reproducer/.venv/lib/python3.8/site-packages/setuptools/_vendor/importlib_metadata/_itertools.py", line 16, in unique_everseen
k = key(element)
AttributeError: 'PathDistribution' object has no attribute '_normalized_name'