GH-77609: Add recurse_symlinks argument to pathlib.Path.glob() (#11…

…7311)

Replace tri-state `follow_symlinks` with boolean `recurse_symlinks` argument. The new argument controls whether symlinks are followed when expanding recursive `**` wildcards. The possible argument values correspond as follows:

    follow_symlinks  recurse_symlinks
    ===============  ================
    False            N/A
    None             False
    True             True

We therefore drop support for not following symlinks when expanding non-recursive pattern parts; it wasn't requested in the original issue, and it's a feature not found in any shells.

This makes the API a easier to grok by eliminating `None` as an option.

No news blurb as `follow_symlinks` was new in 3.13.

Doc/library/pathlib.rst

@@ -985,7 +985,7 @@ call fails (for example because the path doesn't exist).
  .. versionadded:: 3.5
 
 
-.. method:: Path.glob(pattern, *, case_sensitive=None, follow_symlinks=None)
+.. method:: Path.glob(pattern, *, case_sensitive=None, recurse_symlinks=False)
 
  Glob the given relative *pattern* in the directory represented by this path,
  yielding all matching files (of any kind)::
@@ -1013,28 +1013,23 @@ call fails (for example because the path doesn't exist).
  typically, case-sensitive on POSIX, and case-insensitive on Windows.
  Set *case_sensitive* to ``True`` or ``False`` to override this behaviour.
 
- By default, or when the *follow_symlinks* keyword-only argument is set to
- ``None``, this method follows symlinks except when expanding "``**``"
- wildcards. Set *follow_symlinks* to ``True`` to always follow symlinks, or
- ``False`` to treat all symlinks as files.
-
- .. tip::
- Set *follow_symlinks* to ``True`` or ``False`` to improve performance
- of recursive globbing.
+ By default, or when the *recurse_symlinks* keyword-only argument is set to
+ ``False``, this method follows symlinks except when expanding "``**``"
+ wildcards. Set *recurse_symlinks* to ``True`` to always follow symlinks.
 
  .. audit-event:: pathlib.Path.glob self,pattern pathlib.Path.glob
 
  .. versionchanged:: 3.12
  The *case_sensitive* parameter was added.
 
  .. versionchanged:: 3.13
- The *follow_symlinks* parameter was added.
+ The *recurse_symlinks* parameter was added.
 
  .. versionchanged:: 3.13
  The *pattern* parameter accepts a :term:`path-like object`.
 
 
-.. method:: Path.rglob(pattern, *, case_sensitive=None, follow_symlinks=None)
+.. method:: Path.rglob(pattern, *, case_sensitive=None, recurse_symlinks=False)
 
  Glob the given relative *pattern* recursively. This is like calling
  :func:`Path.glob` with "``**/``" added in front of the *pattern*.
@@ -1048,7 +1043,7 @@ call fails (for example because the path doesn't exist).
  The *case_sensitive* parameter was added.
 
  .. versionchanged:: 3.13
- The *follow_symlinks* parameter was added.
+ The *recurse_symlinks* parameter was added.
 
  .. versionchanged:: 3.13
  The *pattern* parameter accepts a :term:`path-like object`.
@@ -1675,7 +1670,7 @@ The patterns accepted and results generated by :meth:`Path.glob` and
  passing ``recursive=True`` to :func:`glob.glob`.
 3. "``**``" pattern components do not follow symlinks by default in pathlib.
  This behaviour has no equivalent in :func:`glob.glob`, but you can pass
- ``follow_symlinks=True`` to :meth:`Path.glob` for compatible behaviour.
+ ``recurse_symlinks=True`` to :meth:`Path.glob` for compatible behaviour.
 4. Like all :class:`PurePath` and :class:`Path` objects, the values returned
  from :meth:`Path.glob` and :meth:`Path.rglob` don't include trailing
  slashes.

Doc/whatsnew/3.13.rst

@@ -559,12 +559,15 @@ pathlib
  implementation of :mod:`os.path` used for low-level path parsing and
  joining: either ``posixpath`` or ``ntpath``.
 
-* Add *follow_symlinks* keyword-only argument to :meth:`pathlib.Path.glob`,
- :meth:`~pathlib.Path.rglob`, :meth:`~pathlib.Path.is_file`,
+* Add *recurse_symlinks* keyword-only argument to :meth:`pathlib.Path.glob`
+ and :meth:`~pathlib.Path.rglob`.
+ (Contributed by Barney Gale in :gh:`77609`).
+
+* Add *follow_symlinks* keyword-only argument to :meth:`~pathlib.Path.is_file`,
  :meth:`~pathlib.Path.is_dir`, :meth:`~pathlib.Path.owner`,
  :meth:`~pathlib.Path.group`.
- (Contributed by Barney Gale in :gh:`77609` and :gh:`105793`, and
- Kamil Turek in :gh:`107962`).
+ (Contributed by Barney Gale in :gh:`105793`, and Kamil Turek in
+ :gh:`107962`).
 
 * Return files and directories from :meth:`pathlib.Path.glob` and
  :meth:`~pathlib.Path.rglob` when given a pattern that ends with "``**``". In

Lib/pathlib/__init__.py

@@ -619,17 +619,17 @@ def _make_child_relpath(self, name):
  path._tail_cached = tail + [name]
  return path
 
- def glob(self, pattern, *, case_sensitive=None, follow_symlinks=None):
+ def glob(self, pattern, *, case_sensitive=None, recurse_symlinks=False):
  """Iterate over this subtree and yield all existing files (of any
  kind, including directories) matching the given relative pattern.
  """
  sys.audit("pathlib.Path.glob", self, pattern)
  if not isinstance(pattern, PurePath):
  pattern = self.with_segments(pattern)
  return _abc.PathBase.glob(
- self, pattern, case_sensitive=case_sensitive, follow_symlinks=follow_symlinks)
+ self, pattern, case_sensitive=case_sensitive, recurse_symlinks=recurse_symlinks)
 
- def rglob(self, pattern, *, case_sensitive=None, follow_symlinks=None):
+ def rglob(self, pattern, *, case_sensitive=None, recurse_symlinks=False):
  """Recursively yield all existing files (of any kind, including
  directories) matching the given relative pattern, anywhere in
  this subtree.
@@ -639,7 +639,7 @@ def rglob(self, pattern, *, case_sensitive=None, follow_symlinks=None):
  pattern = self.with_segments(pattern)
  pattern = '**' / pattern
  return _abc.PathBase.glob(
- self, pattern, case_sensitive=case_sensitive, follow_symlinks=follow_symlinks)
+ self, pattern, case_sensitive=case_sensitive, recurse_symlinks=recurse_symlinks)
 
  def walk(self, top_down=True, on_error=None, follow_symlinks=False):
  """Walk the directory tree from this directory, similar to os.walk()."""

Lib/pathlib/_abc.py

@@ -66,10 +66,8 @@ def _select_special(paths, part):
  yield path._make_child_relpath(part)
 
 
-def _select_children(parent_paths, dir_only, follow_symlinks, match):
+def _select_children(parent_paths, dir_only, match):
  """Yield direct children of given paths, filtering by name and type."""
- if follow_symlinks is None:
- follow_symlinks = True
  for parent_path in parent_paths:
  try:
  # We must close the scandir() object before proceeding to
@@ -82,7 +80,7 @@ def _select_children(parent_paths, dir_only, follow_symlinks, match):
  for entry in entries:
  if dir_only:
  try:
- if not entry.is_dir(follow_symlinks=follow_symlinks):
+ if not entry.is_dir():
  continue
  except OSError:
  continue
@@ -96,8 +94,6 @@ def _select_recursive(parent_paths, dir_only, follow_symlinks, match):
  """Yield given paths and all their children, recursively, filtering by
  string and type.
  """
- if follow_symlinks is None:
- follow_symlinks = False
  for parent_path in parent_paths:
  if match is not None:
  # If we're filtering paths through a regex, record the length of
@@ -789,7 +785,7 @@ def _make_child_direntry(self, entry):
  def _make_child_relpath(self, name):
  return self.joinpath(name)
 
- def glob(self, pattern, *, case_sensitive=None, follow_symlinks=True):
+ def glob(self, pattern, *, case_sensitive=None, recurse_symlinks=True):
  """Iterate over this subtree and yield all existing files (of any
  kind, including directories) matching the given relative pattern.
  """
@@ -818,7 +814,7 @@ def glob(self, pattern, *, case_sensitive=None, follow_symlinks=True):
  # Consume following non-special components, provided we're
  # treating symlinks consistently. Each component is joined
  # onto 'part', which is used to generate an re.Pattern object.
- if follow_symlinks is not None:
+ if recurse_symlinks:
  while stack and stack[-1] not in specials:
  part += sep + stack.pop()
 
@@ -827,7 +823,7 @@ def glob(self, pattern, *, case_sensitive=None, follow_symlinks=True):
  match = _compile_pattern(part, sep, case_sensitive) if part != '**' else None
 
  # Recursively walk directories, filtering by type and regex.
- paths = _select_recursive(paths, bool(stack), follow_symlinks, match)
+ paths = _select_recursive(paths, bool(stack), recurse_symlinks, match)
 
  # De-duplicate if we've already seen a '**' component.
  if deduplicate_paths:
@@ -843,18 +839,18 @@ def glob(self, pattern, *, case_sensitive=None, follow_symlinks=True):
  match = _compile_pattern(part, sep, case_sensitive) if part != '*' else None
 
  # Iterate over directories' children filtering by type and regex.
- paths = _select_children(paths, bool(stack), follow_symlinks, match)
+ paths = _select_children(paths, bool(stack), match)
  return paths
 
- def rglob(self, pattern, *, case_sensitive=None, follow_symlinks=True):
+ def rglob(self, pattern, *, case_sensitive=None, recurse_symlinks=True):
  """Recursively yield all existing files (of any kind, including
  directories) matching the given relative pattern, anywhere in
  this subtree.
  """
  if not isinstance(pattern, PurePathBase):
  pattern = self.with_segments(pattern)
  pattern = '**' / pattern
- return self.glob(pattern, case_sensitive=case_sensitive, follow_symlinks=follow_symlinks)
+ return self.glob(pattern, case_sensitive=case_sensitive, recurse_symlinks=recurse_symlinks)
 
  def walk(self, top_down=True, on_error=None, follow_symlinks=False):
  """Walk the directory tree from this directory, similar to os.walk()."""

Lib/test/test_pathlib/test_pathlib_abc.py

@@ -1776,9 +1776,9 @@ def _check(path, pattern, case_sensitive, expected):
  _check(path, "dirb/file*", False, ["dirB/fileB"])
 
  @needs_symlinks
- def test_glob_follow_symlinks_common(self):
+ def test_glob_recurse_symlinks_common(self):
  def _check(path, glob, expected):
- actual = {path for path in path.glob(glob, follow_symlinks=True)
+ actual = {path for path in path.glob(glob, recurse_symlinks=True)
  if path.parts.count("linkD") <= 1} # exclude symlink loop.
  self.assertEqual(actual, { P(self.base, q) for q in expected })
  P = self.cls
@@ -1812,39 +1812,9 @@ def _check(path, glob, expected):
  _check(p, "*/dirD/**", ["dirC/dirD/", "dirC/dirD/fileD"])
  _check(p, "*/dirD/**/", ["dirC/dirD/"])
 
- @needs_symlinks
- def test_glob_no_follow_symlinks_common(self):
- def _check(path, glob, expected):
- actual = {path for path in path.glob(glob, follow_symlinks=False)}
- self.assertEqual(actual, { P(self.base, q) for q in expected })
- P = self.cls
- p = P(self.base)
- _check(p, "fileB", [])
- _check(p, "dir*/file*", ["dirB/fileB", "dirC/fileC"])
- _check(p, "*A", ["dirA", "fileA", "linkA"])
- _check(p, "*B/*", ["dirB/fileB", "dirB/linkD"])
- _check(p, "*/fileB", ["dirB/fileB"])
- _check(p, "*/", ["dirA/", "dirB/", "dirC/", "dirE/"])
- _check(p, "dir*/*/..", ["dirC/dirD/.."])
- _check(p, "dir*/**", [
- "dirA/", "dirA/linkC",
- "dirB/", "dirB/fileB", "dirB/linkD",
- "dirC/", "dirC/fileC", "dirC/dirD", "dirC/dirD/fileD", "dirC/novel.txt",
- "dirE/"])
- _check(p, "dir*/**/", ["dirA/", "dirB/", "dirC/", "dirC/dirD/", "dirE/"])
- _check(p, "dir*/**/..", ["dirA/..", "dirB/..", "dirC/..", "dirC/dirD/..", "dirE/.."])
- _check(p, "dir*/*/**", ["dirC/dirD/", "dirC/dirD/fileD"])
- _check(p, "dir*/*/**/", ["dirC/dirD/"])
- _check(p, "dir*/*/**/..", ["dirC/dirD/.."])
- _check(p, "dir*/**/fileC", ["dirC/fileC"])
- _check(p, "dir*/*/../dirD/**", ["dirC/dirD/../dirD/", "dirC/dirD/../dirD/fileD"])
- _check(p, "dir*/*/../dirD/**/", ["dirC/dirD/../dirD/"])
- _check(p, "*/dirD/**", ["dirC/dirD/", "dirC/dirD/fileD"])
- _check(p, "*/dirD/**/", ["dirC/dirD/"])
-
- def test_rglob_follow_symlinks_none(self):
+ def test_rglob_recurse_symlinks_false(self):
  def _check(path, glob, expected):
- actual = set(path.rglob(glob, follow_symlinks=None))
+ actual = set(path.rglob(glob, recurse_symlinks=False))
  self.assertEqual(actual, { P(self.base, q) for q in expected })
  P = self.cls
  p = P(self.base)
@@ -1901,9 +1871,9 @@ def test_rglob_windows(self):
  self.assertEqual(set(map(str, p.rglob("FILEd"))), {f"{p}\\dirD\\fileD"})
 
  @needs_symlinks
- def test_rglob_follow_symlinks_common(self):
+ def test_rglob_recurse_symlinks_common(self):
  def _check(path, glob, expected):
- actual = {path for path in path.rglob(glob, follow_symlinks=True)
+ actual = {path for path in path.rglob(glob, recurse_symlinks=True)
  if path.parts.count("linkD") <= 1} # exclude symlink loop.
  self.assertEqual(actual, { P(self.base, q) for q in expected })
  P = self.cls
@@ -1932,37 +1902,12 @@ def _check(path, glob, expected):
  _check(p, "*.txt", ["dirC/novel.txt"])
  _check(p, "*.*", ["dirC/novel.txt"])
 
- @needs_symlinks
- def test_rglob_no_follow_symlinks_common(self):
- def _check(path, glob, expected):
- actual = {path for path in path.rglob(glob, follow_symlinks=False)}
- self.assertEqual(actual, { P(self.base, q) for q in expected })
- P = self.cls
- p = P(self.base)
- _check(p, "fileB", ["dirB/fileB"])
- _check(p, "*/fileA", [])
- _check(p, "*/fileB", ["dirB/fileB"])
- _check(p, "file*", ["fileA", "dirB/fileB", "dirC/fileC", "dirC/dirD/fileD", ])
- _check(p, "*/", ["dirA/", "dirB/", "dirC/", "dirC/dirD/", "dirE/"])
- _check(p, "", ["", "dirA/", "dirB/", "dirC/", "dirE/", "dirC/dirD/"])
-
- p = P(self.base, "dirC")
- _check(p, "*", ["dirC/fileC", "dirC/novel.txt",
- "dirC/dirD", "dirC/dirD/fileD"])
- _check(p, "file*", ["dirC/fileC", "dirC/dirD/fileD"])
- _check(p, "*/*", ["dirC/dirD/fileD"])
- _check(p, "*/", ["dirC/dirD/"])
- _check(p, "", ["dirC/", "dirC/dirD/"])
- # gh-91616, a re module regression
- _check(p, "*.txt", ["dirC/novel.txt"])
- _check(p, "*.*", ["dirC/novel.txt"])
-
  @needs_symlinks
  def test_rglob_symlink_loop(self):
  # Don't get fooled by symlink loops (Issue #26012).
  P = self.cls
  p = P(self.base)
- given = set(p.rglob('*', follow_symlinks=None))
+ given = set(p.rglob('*', recurse_symlinks=False))
  expect = {'brokenLink',
  'dirA', 'dirA/linkC',
  'dirB', 'dirB/fileB', 'dirB/linkD',