Port Pipenv pythonfinder behavior upstream

news/3855.feature.rst

@@ -0,0 +1 @@
+Add ``Finder(pyenv_only=True)`` to restrict discovery to pyenv-managed Python installations.

news/4898.bugfix.rst

@@ -0,0 +1 @@
+Treat any ``Path.exists()`` ``OSError`` as an inaccessible path during discovery, allowing FUSE and network mount failures to be skipped cleanly.

src/pythonfinder/pythonfinder.py

@@ -32,6 +32,7 @@ def __init__(
         global_search: bool = True,
         ignore_unsupported: bool = True,
         sort_by_path: bool = False,
+        pyenv_only: bool = False,
     ):
         """
         Initialize a new Finder.
@@ -41,54 +42,63 @@ def __init__(
             system: Whether to include the system Python.
             global_search: Whether to search in the system PATH.
             ignore_unsupported: Whether to ignore unsupported Python versions.
+            pyenv_only: Whether to restrict searches to pyenv-managed Pythons.
         """
         self.path = path
         self.system = system
         self.global_search = global_search
         self.ignore_unsupported = ignore_unsupported
         self.sort_by_path = sort_by_path
+        self.pyenv_only = pyenv_only
 
         # Initialize finders
-        self.system_finder = SystemFinder(
-            paths=[path] if path else None,
-            global_search=global_search,
-            system=system,
-            ignore_unsupported=ignore_unsupported,
-        )
-
         self.pyenv_finder = PyenvFinder(
             ignore_unsupported=ignore_unsupported,
         )
 
-        self.asdf_finder = AsdfFinder(
-            ignore_unsupported=ignore_unsupported,
-        )
-
-        # Initialize Windows-specific finders if on Windows
-        self.py_launcher_finder = None
-        self.windows_finder = None
-        if os.name == "nt":
-            self.py_launcher_finder = PyLauncherFinder(
+        if pyenv_only:
+            self.system_finder = None
+            self.asdf_finder = None
+            self.py_launcher_finder = None
+            self.windows_finder = None
+            self.finders: list[BaseFinder] = [self.pyenv_finder]
+        else:
+            self.system_finder = SystemFinder(
+                paths=[path] if path else None,
+                global_search=global_search,
+                system=system,
                 ignore_unsupported=ignore_unsupported,
             )
-            self.windows_finder = WindowsRegistryFinder(
+
+            self.asdf_finder = AsdfFinder(
                 ignore_unsupported=ignore_unsupported,
             )
 
-        # List of all finders
-        self.finders: list[BaseFinder] = [
-            self.pyenv_finder,
-            self.asdf_finder,
-        ]
-
-        # Add Windows-specific finders if on Windows
-        if self.py_launcher_finder:
-            self.finders.append(self.py_launcher_finder)
-        if self.windows_finder:
-            self.finders.append(self.windows_finder)
-
-        # Add system finder last
-        self.finders.append(self.system_finder)
+            # Initialize Windows-specific finders if on Windows
+            self.py_launcher_finder = None
+            self.windows_finder = None
+            if os.name == "nt":
+                self.py_launcher_finder = PyLauncherFinder(
+                    ignore_unsupported=ignore_unsupported,
+                )
+                self.windows_finder = WindowsRegistryFinder(
+                    ignore_unsupported=ignore_unsupported,
+                )
+
+            # List of all finders
+            self.finders: list[BaseFinder] = [
+                self.pyenv_finder,
+                self.asdf_finder,
+            ]
+
+            # Add Windows-specific finders if on Windows
+            if self.py_launcher_finder:
+                self.finders.append(self.py_launcher_finder)
+            if self.windows_finder:
+                self.finders.append(self.windows_finder)
+
+            # Add system finder last
+            self.finders.append(self.system_finder)
 
     def which(self, executable: str) -> Path | None:
         """

src/pythonfinder/utils/path_utils.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import errno
 import os
 import re
 from pathlib import Path
@@ -230,6 +229,11 @@ def exists_and_is_accessible(path: Path) -> bool:
     """
     Check if a path exists and is accessible.
 
+    Catches all ``OSError`` subclasses (including ``PermissionError``) and
+    returns ``False`` so that network mounts, FUSE filesystems, and other
+    special paths that raise unexpected error codes are silently skipped
+    instead of propagating an unhandled exception.
+
     Args:
         path: The path to check.
 
@@ -238,14 +242,8 @@ def exists_and_is_accessible(path: Path) -> bool:
     """
     try:
         return path.exists()
-    except PermissionError as error:
-        if error.errno == errno.EACCES or getattr(error, "winerror", None) == 5:
-            return False
-        raise
-    except OSError as error:
-        if error.errno == errno.EACCES or getattr(error, "winerror", None) == 5:
-            return False
-        raise
+    except OSError:
+        return False
 
 
 def is_in_path(path: str | Path, parent_path: str | Path) -> bool:

tests/test_finder.py

@@ -34,6 +34,19 @@ def test_finder_initialization():
         assert finder.windows_finder is not None
 
 
+def test_finder_pyenv_only_initialization():
+    """Test that pyenv_only restricts the finder list to pyenv."""
+    finder = Finder(system=True, global_search=True, pyenv_only=True)
+
+    assert finder.pyenv_only is True
+    assert finder.pyenv_finder is not None
+    assert finder.system_finder is None
+    assert finder.asdf_finder is None
+    assert finder.py_launcher_finder is None
+    assert finder.windows_finder is None
+    assert finder.finders == [finder.pyenv_finder]
+
+
 def test_which_method():
     """Test the which method to find an executable."""
     finder = Finder(system=True, global_search=True)

tests/test_path_utils.py

@@ -4,8 +4,6 @@
 from pathlib import Path
 from unittest import mock
 
-import pytest
-
 from pythonfinder.utils.path_utils import (
     ensure_path,
     exists_and_is_accessible,
@@ -234,12 +232,10 @@ def test_exists_and_is_accessible():
     ):
         assert not exists_and_is_accessible(Path("/usr/bin/python"))
 
-    # Test with other error
-    with pytest.raises(PermissionError):
-        with mock.patch(
-            "pathlib.Path.exists", side_effect=PermissionError(1, "Other error")
-        ):
-            exists_and_is_accessible(Path("/usr/bin/python"))
+    with mock.patch(
+        "pathlib.Path.exists", side_effect=PermissionError(1, "Other error")
+    ):
+        assert not exists_and_is_accessible(Path("/usr/bin/python"))
 
     class WindowsAccessDenied(OSError):
         def __init__(self):
@@ -250,9 +246,8 @@ def __init__(self):
     with mock.patch("pathlib.Path.exists", side_effect=WindowsAccessDenied()):
         assert not exists_and_is_accessible(Path("/usr/bin/python"))
 
-    with pytest.raises(OSError):
-        with mock.patch("pathlib.Path.exists", side_effect=OSError(1, "Other error")):
-            exists_and_is_accessible(Path("/usr/bin/python"))
+    with mock.patch("pathlib.Path.exists", side_effect=OSError(1, "Other error")):
+        assert not exists_and_is_accessible(Path("/usr/bin/python"))
 
 
 def test_is_in_path():