[Python-checkins] bpo-39682: make `pathlib.Path` immutable by removing (undocumented) support for "closing" a path by using it as a context manager (GH-18846)
Barney Gale
webhook-mailer at python.org
Wed Apr 1 10:11:01 EDT 2020
https://github.com/python/cpython/commit/00002e6d8b0ccdb6e0d9e98a9a7f9c9edfdf1311
commit: 00002e6d8b0ccdb6e0d9e98a9a7f9c9edfdf1311
branch: master
author: Barney Gale <barney.gale at gmail.com>
committer: GitHub <noreply at github.com>
date: 2020-04-01T16:10:51+02:00
summary:
bpo-39682: make `pathlib.Path` immutable by removing (undocumented) support for "closing" a path by using it as a context manager (GH-18846)
Support for using a path as a context manager remains, and is now a no-op.
files:
A Misc/NEWS.d/next/Library/2020-03-08-11-00-01.bpo-39682.AxXZNz.rst
M Lib/pathlib.py
M Lib/test/test_pathlib.py
diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index 293462000c2a6..96b8b59530c72 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -1041,7 +1041,6 @@ class Path(PurePath):
"""
__slots__ = (
'_accessor',
- '_closed',
)
def __new__(cls, *args, **kwargs):
@@ -1058,7 +1057,6 @@ def _init(self,
# Private non-constructor arguments
template=None,
):
- self._closed = False
if template is not None:
self._accessor = template._accessor
else:
@@ -1071,15 +1069,18 @@ def _make_child_relpath(self, part):
return self._from_parsed_parts(self._drv, self._root, parts)
def __enter__(self):
- if self._closed:
- self._raise_closed()
return self
def __exit__(self, t, v, tb):
- self._closed = True
-
- def _raise_closed(self):
- raise ValueError("I/O operation on closed path")
+ # https://bugs.python.org/issue39682
+ # In previous versions of pathlib, this method marked this path as
+ # closed; subsequent attempts to perform I/O would raise an IOError.
+ # This functionality was never documented, and had the effect of
+ # making Path objects mutable, contrary to PEP 428. In Python 3.9 the
+ # _closed attribute was removed, and this method made a no-op.
+ # This method and __enter__()/__exit__() should be deprecated and
+ # removed in the future.
+ pass
def _opener(self, name, flags, mode=0o666):
# A stub for the opener argument to built-in open()
@@ -1090,8 +1091,6 @@ def _raw_open(self, flags, mode=0o777):
Open the file pointed by this path and return a file descriptor,
as os.open() does.
"""
- if self._closed:
- self._raise_closed()
return self._accessor.open(self, flags, mode)
# Public API
@@ -1125,15 +1124,11 @@ def iterdir(self):
"""Iterate over the files in this directory. Does not yield any
result for the special paths '.' and '..'.
"""
- if self._closed:
- self._raise_closed()
for name in self._accessor.listdir(self):
if name in {'.', '..'}:
# Yielding a path object for these makes little sense
continue
yield self._make_child_relpath(name)
- if self._closed:
- self._raise_closed()
def glob(self, pattern):
"""Iterate over this subtree and yield all existing files (of any
@@ -1170,8 +1165,6 @@ def absolute(self):
Use resolve() to get the canonical path to a file.
"""
# XXX untested yet!
- if self._closed:
- self._raise_closed()
if self.is_absolute():
return self
# FIXME this must defer to the specific flavour (and, under Windows,
@@ -1186,8 +1179,6 @@ def resolve(self, strict=False):
normalizing it (for example turning slashes into backslashes under
Windows).
"""
- if self._closed:
- self._raise_closed()
s = self._flavour.resolve(self, strict=strict)
if s is None:
# No symlink resolution => for consistency, raise an error if
@@ -1227,8 +1218,6 @@ def open(self, mode='r', buffering=-1, encoding=None,
Open the file pointed by this path and return a file object, as
the built-in open() function does.
"""
- if self._closed:
- self._raise_closed()
return io.open(self, mode, buffering, encoding, errors, newline,
opener=self._opener)
@@ -1278,8 +1267,6 @@ def touch(self, mode=0o666, exist_ok=True):
"""
Create this file with the given access mode, if it doesn't exist.
"""
- if self._closed:
- self._raise_closed()
if exist_ok:
# First try to bump modification time
# Implementation note: GNU touch uses the UTIME_NOW option of
@@ -1301,8 +1288,6 @@ def mkdir(self, mode=0o777, parents=False, exist_ok=False):
"""
Create a new directory at this given path.
"""
- if self._closed:
- self._raise_closed()
try:
self._accessor.mkdir(self, mode)
except FileNotFoundError:
@@ -1320,8 +1305,6 @@ def chmod(self, mode):
"""
Change the permissions of the path, like os.chmod().
"""
- if self._closed:
- self._raise_closed()
self._accessor.chmod(self, mode)
def lchmod(self, mode):
@@ -1329,8 +1312,6 @@ def lchmod(self, mode):
Like chmod(), except if the path points to a symlink, the symlink's
permissions are changed, rather than its target's.
"""
- if self._closed:
- self._raise_closed()
self._accessor.lchmod(self, mode)
def unlink(self, missing_ok=False):
@@ -1338,8 +1319,6 @@ def unlink(self, missing_ok=False):
Remove this file or link.
If the path is a directory, use rmdir() instead.
"""
- if self._closed:
- self._raise_closed()
try:
self._accessor.unlink(self)
except FileNotFoundError:
@@ -1350,8 +1329,6 @@ def rmdir(self):
"""
Remove this directory. The directory must be empty.
"""
- if self._closed:
- self._raise_closed()
self._accessor.rmdir(self)
def lstat(self):
@@ -1359,16 +1336,12 @@ def lstat(self):
Like stat(), except if the path points to a symlink, the symlink's
status information is returned, rather than its target's.
"""
- if self._closed:
- self._raise_closed()
return self._accessor.lstat(self)
def link_to(self, target):
"""
Create a hard link pointing to a path named target.
"""
- if self._closed:
- self._raise_closed()
self._accessor.link_to(self, target)
def rename(self, target):
@@ -1376,8 +1349,6 @@ def rename(self, target):
Rename this path to the given path,
and return a new Path instance pointing to the given path.
"""
- if self._closed:
- self._raise_closed()
self._accessor.rename(self, target)
return self.__class__(target)
@@ -1387,8 +1358,6 @@ def replace(self, target):
destination if it exists, and return a new Path instance
pointing to the given path.
"""
- if self._closed:
- self._raise_closed()
self._accessor.replace(self, target)
return self.__class__(target)
@@ -1397,8 +1366,6 @@ def symlink_to(self, target, target_is_directory=False):
Make this path a symlink pointing to the given path.
Note the order of arguments (self, target) is the reverse of os.symlink's.
"""
- if self._closed:
- self._raise_closed()
self._accessor.symlink(target, self, target_is_directory)
# Convenience functions for querying the stat results
diff --git a/Lib/test/test_pathlib.py b/Lib/test/test_pathlib.py
index 5b362a0ff3d9b..8b19cffba37e9 100644
--- a/Lib/test/test_pathlib.py
+++ b/Lib/test/test_pathlib.py
@@ -1720,13 +1720,15 @@ def test_with(self):
next(it2)
with p:
pass
- # I/O operation on closed path.
- self.assertRaises(ValueError, next, it)
- self.assertRaises(ValueError, next, it2)
- self.assertRaises(ValueError, p.open)
- self.assertRaises(ValueError, p.resolve)
- self.assertRaises(ValueError, p.absolute)
- self.assertRaises(ValueError, p.__enter__)
+ # Using a path as a context manager is a no-op, thus the following
+ # operations should still succeed after the context manage exits.
+ next(it)
+ next(it2)
+ p.exists()
+ p.resolve()
+ p.absolute()
+ with p:
+ pass
def test_chmod(self):
p = self.cls(BASE) / 'fileA'
diff --git a/Misc/NEWS.d/next/Library/2020-03-08-11-00-01.bpo-39682.AxXZNz.rst b/Misc/NEWS.d/next/Library/2020-03-08-11-00-01.bpo-39682.AxXZNz.rst
new file mode 100644
index 0000000000000..d71a32132af9d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-03-08-11-00-01.bpo-39682.AxXZNz.rst
@@ -0,0 +1,3 @@
+Remove undocumented support for *closing* a `pathlib.Path` object via its
+context manager. The context manager magic methods remain, but they are now a
+no-op, making `Path` objects immutable.
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