https://github.com/python/cpython/commit/1092cfb20179ac7dd6a2c3c6f8a57ecc1732c777
commit: 1092cfb20179ac7dd6a2c3c6f8a57ecc1732c777
branch: main
author: Barney Gale <[email protected]>
committer: barneygale <[email protected]>
date: 2024-01-09T19:50:23Z
summary:
GH-113528: Deoptimise `pathlib._abc.PathBase.resolve()` (#113782)
Replace use of `_from_parsed_parts()` with `with_segments()` in
`resolve()`.
No effect on `Path.resolve()`, which uses `os.path.realpath()`.
files:
M Lib/pathlib/_abc.py
diff --git a/Lib/pathlib/_abc.py b/Lib/pathlib/_abc.py
index 0e442ae4809c36..caa84fc40559f7 100644
--- a/Lib/pathlib/_abc.py
+++ b/Lib/pathlib/_abc.py
@@ -406,6 +406,23 @@ def __rtruediv__(self, key):
except TypeError:
return NotImplemented
+ @property
+ def _stack(self):
+ """
+ Split the path into a 2-tuple (anchor, parts), where *anchor* is the
+ uppermost parent of the path (equivalent to path.parents[-1]), and
+ *parts* is a reversed list of parts following the anchor.
+ """
+ split = self.pathmod.split
+ path = str(self)
+ parent, name = split(path)
+ names = []
+ while path != parent:
+ names.append(name)
+ path = parent
+ parent, name = split(path)
+ return path, names
+
@property
def parent(self):
"""The logical parent of the path."""
@@ -911,16 +928,6 @@ def readlink(self):
self._unsupported("readlink")
readlink._supported = False
- def _split_stack(self):
- """
- Split the path into a 2-tuple (anchor, parts), where *anchor* is the
- uppermost parent of the path (equivalent to path.parents[-1]), and
- *parts* is a reversed list of parts following the anchor.
- """
- if not self._tail:
- return self, []
- return self._from_parsed_parts(self.drive, self.root, []),
self._tail[::-1]
-
def resolve(self, strict=False):
"""
Make the path absolute, resolving all symlinks on the way and also
@@ -928,11 +935,15 @@ def resolve(self, strict=False):
"""
if self._resolving:
return self
- path, parts = self._split_stack()
+ path_root, parts = self._stack
+ path = self.with_segments(path_root)
try:
path = path.absolute()
except UnsupportedOperation:
- pass
+ path_tail = []
+ else:
+ path_root, path_tail = path._stack
+ path_tail.reverse()
# If the user has *not* overridden the `readlink()` method, then
symlinks are unsupported
# and (in non-strict mode) we can improve performance by not calling
`stat()`.
@@ -940,31 +951,37 @@ def resolve(self, strict=False):
link_count = 0
while parts:
part = parts.pop()
+ if not part or part == '.':
+ continue
if part == '..':
- if not path._tail:
- if path.root:
+ if not path_tail:
+ if path_root:
# Delete '..' segment immediately following root
continue
- elif path._tail[-1] != '..':
+ elif path_tail[-1] != '..':
# Delete '..' segment and its predecessor
- path = path.parent
+ path_tail.pop()
continue
- next_path = path._make_child_relpath(part)
+ path_tail.append(part)
if querying and part != '..':
- next_path._resolving = True
+ path = self.with_segments(path_root +
self.pathmod.sep.join(path_tail))
+ path._resolving = True
try:
- st = next_path.stat(follow_symlinks=False)
+ st = path.stat(follow_symlinks=False)
if S_ISLNK(st.st_mode):
# Like Linux and macOS, raise OSError(errno.ELOOP) if
too many symlinks are
# encountered during resolution.
link_count += 1
if link_count >= self._max_symlinks:
raise OSError(ELOOP, "Too many symbolic links in
path", str(self))
- target, target_parts =
next_path.readlink()._split_stack()
+ target_root, target_parts = path.readlink()._stack
# If the symlink target is absolute (like
'/etc/hosts'), set the current
# path to its uppermost parent (like '/').
- if target.root:
- path = target
+ if target_root:
+ path_root = target_root
+ path_tail.clear()
+ else:
+ path_tail.pop()
# Add the symlink target's reversed tail parts (like
['hosts', 'etc']) to
# the stack of unresolved path parts.
parts.extend(target_parts)
@@ -976,9 +993,7 @@ def resolve(self, strict=False):
raise
else:
querying = False
- next_path._resolving = False
- path = next_path
- return path
+ return self.with_segments(path_root + self.pathmod.sep.join(path_tail))
def symlink_to(self, target, target_is_directory=False):
"""
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