GH-101357: Suppress OSError from pathlib.Path.exists() and is_*() (#118243)

Suppress all `OSError` exceptions from `pathlib.Path.exists()` and `is_*()`
rather than a selection of more common errors as we do presently. Also
adjust the implementations to call `os.path.exists()` etc, which are much
faster on Windows thanks to GH-101196.

Doc/library/pathlib.rst

@@ -873,7 +873,7 @@ Methods
 ^^^^^^^
 
 Concrete paths provide the following methods in addition to pure paths
-methods.  Many of these methods can raise an :exc:`OSError` if a system
+methods.  Some of these methods can raise an :exc:`OSError` if a system
 call fails (for example because the path doesn't exist).
 
 .. versionchanged:: 3.8
@@ -885,6 +885,15 @@ call fails (for example because the path doesn't exist).
    instead of raising an exception for paths that contain characters
    unrepresentable at the OS level.
 
+.. versionchanged:: 3.14
+
+   The methods given above now return ``False`` instead of raising any
+   :exc:`OSError` exception from the operating system. In previous versions,
+   some kinds of :exc:`OSError` exception are raised, and others suppressed.
+   The new behaviour is consistent with :func:`os.path.exists`,
+   :func:`os.path.isdir`, etc. Use :meth:`~Path.stat` to retrieve the file
+   status without suppressing exceptions.
+
 
 .. classmethod:: Path.cwd()
 
@@ -951,6 +960,8 @@ call fails (for example because the path doesn't exist).
 .. method:: Path.exists(*, follow_symlinks=True)
 
    Return ``True`` if the path points to an existing file or directory.
+   ``False`` will be returned if the path is invalid, inaccessible or missing.
+   Use :meth:`Path.stat` to distinguish between these cases.
 
    This method normally follows symlinks; to check if a symlink exists, add
    the argument ``follow_symlinks=False``.
@@ -1067,11 +1078,10 @@ call fails (for example because the path doesn't exist).
 
 .. method:: Path.is_dir(*, follow_symlinks=True)
 
-   Return ``True`` if the path points to a directory, ``False`` if it points
+   Return ``True`` if the path points to a directory. ``False`` will be
-   to another kind of file.
+   returned if the path is invalid, inaccessible or missing, or if it points
-
+   to something other than a directory. Use :meth:`Path.stat` to distinguish
-   ``False`` is also returned if the path doesn't exist or is a broken symlink;
+   between these cases.
-   other errors (such as permission errors) are propagated.
 
    This method normally follows symlinks; to exclude symlinks to directories,
    add the argument ``follow_symlinks=False``.
@@ -1082,11 +1092,10 @@ call fails (for example because the path doesn't exist).
 
 .. method:: Path.is_file(*, follow_symlinks=True)
 
-   Return ``True`` if the path points to a regular file, ``False`` if it
+   Return ``True`` if the path points to a regular file. ``False`` will be
-   points to another kind of file.
+   returned if the path is invalid, inaccessible or missing, or if it points
-
+   to something other than a regular file. Use :meth:`Path.stat` to
-   ``False`` is also returned if the path doesn't exist or is a broken symlink;
+   distinguish between these cases.
-   other errors (such as permission errors) are propagated.
 
    This method normally follows symlinks; to exclude symlinks, add the
    argument ``follow_symlinks=False``.
@@ -1122,46 +1131,42 @@ call fails (for example because the path doesn't exist).
 
 .. method:: Path.is_symlink()
 
-   Return ``True`` if the path points to a symbolic link, ``False`` otherwise.
+   Return ``True`` if the path points to a symbolic link, even if that symlink
-
+   is broken. ``False`` will be returned if the path is invalid, inaccessible
-   ``False`` is also returned if the path doesn't exist; other errors (such
+   or missing, or if it points to something other than a symbolic link. Use
-   as permission errors) are propagated.
+   :meth:`Path.stat` to distinguish between these cases.
 
 
 .. method:: Path.is_socket()
 
-   Return ``True`` if the path points to a Unix socket (or a symbolic link
+   Return ``True`` if the path points to a Unix socket. ``False`` will be
-   pointing to a Unix socket), ``False`` if it points to another kind of file.
+   returned if the path is invalid, inaccessible or missing, or if it points
-
+   to something other than a Unix socket. Use :meth:`Path.stat` to
-   ``False`` is also returned if the path doesn't exist or is a broken symlink;
+   distinguish between these cases.
-   other errors (such as permission errors) are propagated.
 
 
 .. method:: Path.is_fifo()
 
-   Return ``True`` if the path points to a FIFO (or a symbolic link
+   Return ``True`` if the path points to a FIFO. ``False`` will be returned if
-   pointing to a FIFO), ``False`` if it points to another kind of file.
+   the path is invalid, inaccessible or missing, or if it points to something
-
+   other than a FIFO. Use :meth:`Path.stat` to distinguish between these
-   ``False`` is also returned if the path doesn't exist or is a broken symlink;
+   cases.
-   other errors (such as permission errors) are propagated.
 
 
 .. method:: Path.is_block_device()
 
-   Return ``True`` if the path points to a block device (or a symbolic link
+   Return ``True`` if the path points to a block device. ``False`` will be
-   pointing to a block device), ``False`` if it points to another kind of file.
+   returned if the path is invalid, inaccessible or missing, or if it points
-
+   to something other than a block device. Use :meth:`Path.stat` to
-   ``False`` is also returned if the path doesn't exist or is a broken symlink;
+   distinguish between these cases.
-   other errors (such as permission errors) are propagated.
 
 
 .. method:: Path.is_char_device()
 
-   Return ``True`` if the path points to a character device (or a symbolic link
+   Return ``True`` if the path points to a character device. ``False`` will be
-   pointing to a character device), ``False`` if it points to another kind of file.
+   returned if the path is invalid, inaccessible or missing, or if it points
-
+   to something other than a character device. Use :meth:`Path.stat` to
-   ``False`` is also returned if the path doesn't exist or is a broken symlink;
+   distinguish between these cases.
-   other errors (such as permission errors) are propagated.
 
 
 .. method:: Path.iterdir()

Lib/glob.py

@@ -340,7 +340,7 @@ class _Globber:
 
     # Low-level methods
 
-    lstat = operator.methodcaller('lstat')
+    lexists = operator.methodcaller('exists', follow_symlinks=False)
     add_slash = operator.methodcaller('joinpath', '')
 
     @staticmethod
@@ -516,12 +516,8 @@ class _Globber:
             # Optimization: this path is already known to exist, e.g. because
             # it was returned from os.scandir(), so we skip calling lstat().
             yield path
-        else:
+        elif self.lexists(path):
-            try:
-                self.lstat(path)
             yield path
-            except OSError:
-                pass
 
     @classmethod
     def walk(cls, root, top_down, on_error, follow_symlinks):
@@ -562,7 +558,7 @@ class _Globber:
 
 
 class _StringGlobber(_Globber):
-    lstat = staticmethod(os.lstat)
+    lexists = staticmethod(os.path.lexists)
     scandir = staticmethod(os.scandir)
     parse_entry = operator.attrgetter('path')
     concat_path = operator.add

Lib/pathlib/_abc.py

@@ -13,32 +13,12 @@ resemble pathlib's PurePath and Path respectively.
 
 import functools
 from glob import _Globber, _no_recurse_symlinks
-from errno import ENOENT, ENOTDIR, EBADF, ELOOP, EINVAL
+from errno import ENOTDIR, ELOOP
 from stat import S_ISDIR, S_ISLNK, S_ISREG, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO
 
 
 __all__ = ["UnsupportedOperation"]
 
-#
-# Internals
-#
-
-_WINERROR_NOT_READY = 21  # drive exists but is not accessible
-_WINERROR_INVALID_NAME = 123  # fix for bpo-35306
-_WINERROR_CANT_RESOLVE_FILENAME = 1921  # broken symlink pointing to itself
-
-# EBADF - guard against macOS `stat` throwing EBADF
-_IGNORED_ERRNOS = (ENOENT, ENOTDIR, EBADF, ELOOP)
-
-_IGNORED_WINERRORS = (
-    _WINERROR_NOT_READY,
-    _WINERROR_INVALID_NAME,
-    _WINERROR_CANT_RESOLVE_FILENAME)
-
-def _ignore_error(exception):
-    return (getattr(exception, 'errno', None) in _IGNORED_ERRNOS or
-            getattr(exception, 'winerror', None) in _IGNORED_WINERRORS)
-
 
 @functools.cache
 def _is_case_sensitive(parser):
@@ -450,12 +430,7 @@ class PathBase(PurePathBase):
         """
         try:
             self.stat(follow_symlinks=follow_symlinks)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
         return True
 
@@ -465,14 +440,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISDIR(self.stat(follow_symlinks=follow_symlinks).st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist or is a broken symlink
-            # (see http://web.archive.org/web/20200623061726/https://bitbucket.org/pitrou/pathlib/issues/12/ )
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def is_file(self, *, follow_symlinks=True):
@@ -482,14 +450,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISREG(self.stat(follow_symlinks=follow_symlinks).st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist or is a broken symlink
-            # (see http://web.archive.org/web/20200623061726/https://bitbucket.org/pitrou/pathlib/issues/12/ )
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def is_mount(self):
@@ -518,13 +479,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISLNK(self.lstat().st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def is_junction(self):
@@ -542,14 +497,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISBLK(self.stat().st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist or is a broken symlink
-            # (see http://web.archive.org/web/20200623061726/https://bitbucket.org/pitrou/pathlib/issues/12/ )
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def is_char_device(self):
@@ -558,14 +506,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISCHR(self.stat().st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist or is a broken symlink
-            # (see http://web.archive.org/web/20200623061726/https://bitbucket.org/pitrou/pathlib/issues/12/ )
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def is_fifo(self):
@@ -574,14 +515,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISFIFO(self.stat().st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist or is a broken symlink
-            # (see http://web.archive.org/web/20200623061726/https://bitbucket.org/pitrou/pathlib/issues/12/ )
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def is_socket(self):
@@ -590,14 +524,7 @@ class PathBase(PurePathBase):
         """
         try:
             return S_ISSOCK(self.stat().st_mode)
-        except OSError as e:
+        except (OSError, ValueError):
-            if not _ignore_error(e):
-                raise
-            # Path doesn't exist or is a broken symlink
-            # (see http://web.archive.org/web/20200623061726/https://bitbucket.org/pitrou/pathlib/issues/12/ )
-            return False
-        except ValueError:
-            # Non-encodable path
             return False
 
     def samefile(self, other_path):

Lib/pathlib/_local.py

@@ -502,12 +502,46 @@ class Path(PathBase, PurePath):
         """
         return os.stat(self, follow_symlinks=follow_symlinks)
 
+    def exists(self, *, follow_symlinks=True):
+        """
+        Whether this path exists.
+
+        This method normally follows symlinks; to check whether a symlink exists,
+        add the argument follow_symlinks=False.
+        """
+        if follow_symlinks:
+            return os.path.exists(self)
+        return os.path.lexists(self)
+
+    def is_dir(self, *, follow_symlinks=True):
+        """
+        Whether this path is a directory.
+        """
+        if follow_symlinks:
+            return os.path.isdir(self)
+        return PathBase.is_dir(self, follow_symlinks=follow_symlinks)
+
+    def is_file(self, *, follow_symlinks=True):
+        """
+        Whether this path is a regular file (also True for symlinks pointing
+        to regular files).
+        """
+        if follow_symlinks:
+            return os.path.isfile(self)
+        return PathBase.is_file(self, follow_symlinks=follow_symlinks)
+
     def is_mount(self):
         """
         Check if this path is a mount point
         """
         return os.path.ismount(self)
 
+    def is_symlink(self):
+        """
+        Whether this path is a symbolic link.
+        """
+        return os.path.islink(self)
+
     def is_junction(self):
         """
         Whether this path is a junction.

Misc/NEWS.d/next/Library/2024-05-08-19-47-34.gh-issue-101357.e4R_9x.rst

@@ -0,0 +1,5 @@
+Suppress all :exc:`OSError` exceptions from :meth:`pathlib.Path.exists` and
+``is_*()`` methods, rather than a selection of more common errors. The new
+behaviour is consistent with :func:`os.path.exists`, :func:`os.path.isdir`,
+etc. Use :meth:`Path.stat` to retrieve the file status without suppressing
+exceptions.