InvalidPythonVersion with dangling symlink via Finder.find_all_python_versions

[blueyed]

Given a dangling symlink in a $PATH entry you will get an error:

t.py:

from pythonfinder import Finder

finder = Finder()
print(finder.find_all_python_versions())

% python t.py
Traceback (most recent call last):
  File "…/Vcs/pythonfinder/t.py", line 4, in <module>
    print(finder.find_all_python_versions())
  File "…/Vcs/pythonfinder/src/pythonfinder/pythonfinder.py", line 322, in find_all_python_versions
    versions = self.system_path.find_all_python_versions(
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 547, in find_all_python_versions
    values = list(self.get_pythons(sub_finder))
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 505, in get_pythons
    pythons = [entry for entry in self._get_all_pythons(finder)]
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 505, in <listcomp>
    pythons = [entry for entry in self._get_all_pythons(finder)]
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 498, in _get_all_pythons
    for python in self._filter_paths(finder):
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 490, in _filter_paths
    python_versions = finder(path)
  File "…/Vcs/pythonfinder/src/pythonfinder/models/mixins.py", line 330, in find_all_python_versions
    unnested = [sub_finder(path) for path in expand_paths(self)]
  File "…/Vcs/pythonfinder/src/pythonfinder/models/mixins.py", line 330, in <listcomp>
    unnested = [sub_finder(path) for path in expand_paths(self)]
  File "…/Vcs/pythonfinder/src/pythonfinder/utils.py", line 433, in expand_paths
    for p in path.children.values():
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 751, in children
    for child_key, child_val in self._gen_children():
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 742, in _gen_children
    entry = PathEntry.create(path=child, **pass_args)  # type: ignore
  File "…/Vcs/pythonfinder/src/pythonfinder/models/path.py", line 782, in create
    raise InvalidPythonVersion("Python interpreter does not exist: {}".format(target))
pythonfinder.exceptions.InvalidPythonVersion: Python interpreter does not exist: /home/user/bin/calm

It appears that a check for a non-existent file / danging symlink should happen in the calling code already maybe: https://github.com/sarugaku/pythonfinder/blob/dfac150ffeaccbcb3c2867c5429b38b568d85a8d/src/pythonfinder/models/path.py#L732-L742 But then it is also not clear to me how/if that is related to the PathEntry being a root entry in the first place, i.e. take this hint with a lot of salt.. ;)

(btw: this also happens with Finder.find_python_version as with the example in the README (https://github.com/sarugaku/pythonfinder/blob/dfac150ffeaccbcb3c2867c5429b38b568d85a8d/README.rst#usage).)