https://github.com/python/cpython/commit/20d5b84f57a6f7e5a76109e483abe39d9f703d56
commit: 20d5b84f57a6f7e5a76109e483abe39d9f703d56
branch: main
author: Barney Gale <[email protected]>
committer: barneygale <[email protected]>
date: 2024-06-19T00:59:54Z
summary:
GH-73991: Add follow_symlinks argument to `pathlib.Path.copy()` (#120519)
Add support for not following symlinks in `pathlib.Path.copy()`.
On Windows we add the `COPY_FILE_COPY_SYMLINK` flag is following symlinks is
disabled. If the source is symlink to a directory, this call will fail with
`ERROR_ACCESS_DENIED`. In this case we add `COPY_FILE_DIRECTORY` to the flags
and retry. This can fail on old Windowses, which we note in the docs.
No news as `copy()` was only just added.
files:
M Doc/library/pathlib.rst
M Lib/pathlib/_abc.py
M Lib/pathlib/_local.py
M Lib/pathlib/_os.py
M Lib/test/test_pathlib/test_pathlib_abc.py
M Modules/_winapi.c
diff --git a/Doc/library/pathlib.rst b/Doc/library/pathlib.rst
index c8a3272d7bab4c..5bfcad0dadff6a 100644
--- a/Doc/library/pathlib.rst
+++ b/Doc/library/pathlib.rst
@@ -1432,17 +1432,26 @@ Creating files and directories
Copying, renaming and deleting
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-.. method:: Path.copy(target)
+.. method:: Path.copy(target, *, follow_symlinks=True)
Copy the contents of this file to the *target* file. If *target* specifies
a file that already exists, it will be replaced.
+ If *follow_symlinks* is false, and this file is a symbolic link, *target*
+ will be created as a symbolic link. If *follow_symlinks* is true and this
+ file is a symbolic link, *target* will be a copy of the symlink target.
+
.. note::
This method uses operating system functionality to copy file content
efficiently. The OS might also copy some metadata, such as file
permissions. After the copy is complete, users may wish to call
:meth:`Path.chmod` to set the permissions of the target file.
+ .. warning::
+ On old builds of Windows (before Windows 10 build 19041), this method
+ raises :exc:`OSError` when a symlink to a directory is encountered and
+ *follow_symlinks* is false.
+
.. versionadded:: 3.14
diff --git a/Lib/pathlib/_abc.py b/Lib/pathlib/_abc.py
index 586145ead384ea..f1f350a196091a 100644
--- a/Lib/pathlib/_abc.py
+++ b/Lib/pathlib/_abc.py
@@ -790,14 +790,19 @@ def mkdir(self, mode=0o777, parents=False,
exist_ok=False):
"""
raise UnsupportedOperation(self._unsupported_msg('mkdir()'))
- def copy(self, target):
+ def copy(self, target, follow_symlinks=True):
"""
- Copy the contents of this file to the given target.
+ Copy the contents of this file to the given target. If this file is a
+ symlink and follow_symlinks is false, a symlink will be created at the
+ target.
"""
if not isinstance(target, PathBase):
target = self.with_segments(target)
if self._samefile_safe(target):
raise OSError(f"{self!r} and {target!r} are the same file")
+ if not follow_symlinks and self.is_symlink():
+ target.symlink_to(self.readlink())
+ return
with self.open('rb') as source_f:
try:
with target.open('wb') as target_f:
diff --git a/Lib/pathlib/_local.py b/Lib/pathlib/_local.py
index cffed10dbd1207..0105ea3042422e 100644
--- a/Lib/pathlib/_local.py
+++ b/Lib/pathlib/_local.py
@@ -782,9 +782,11 @@ def mkdir(self, mode=0o777, parents=False, exist_ok=False):
raise
if copyfile:
- def copy(self, target):
+ def copy(self, target, follow_symlinks=True):
"""
- Copy the contents of this file to the given target.
+ Copy the contents of this file to the given target. If this file
is a
+ symlink and follow_symlinks is false, a symlink will be created at
the
+ target.
"""
try:
target = os.fspath(target)
@@ -792,9 +794,9 @@ def copy(self, target):
if isinstance(target, PathBase):
# Target is an instance of PathBase but not os.PathLike.
# Use generic implementation from PathBase.
- return PathBase.copy(self, target)
+ return PathBase.copy(self, target,
follow_symlinks=follow_symlinks)
raise
- copyfile(os.fspath(self), target)
+ copyfile(os.fspath(self), target, follow_symlinks)
def chmod(self, mode, *, follow_symlinks=True):
"""
diff --git a/Lib/pathlib/_os.py b/Lib/pathlib/_os.py
index 1771d54e4167c1..bbb019b6534503 100644
--- a/Lib/pathlib/_os.py
+++ b/Lib/pathlib/_os.py
@@ -4,6 +4,7 @@
from errno import EBADF, EOPNOTSUPP, ETXTBSY, EXDEV
import os
+import stat
import sys
try:
import fcntl
@@ -91,12 +92,32 @@ def copyfd(source_fd, target_fd):
copyfd = None
-if _winapi and hasattr(_winapi, 'CopyFile2'):
- def copyfile(source, target):
+if _winapi and hasattr(_winapi, 'CopyFile2') and hasattr(os.stat_result,
'st_file_attributes'):
+ def _is_dirlink(path):
+ try:
+ st = os.lstat(path)
+ except (OSError, ValueError):
+ return False
+ return (st.st_file_attributes & stat.FILE_ATTRIBUTE_DIRECTORY and
+ st.st_reparse_tag == stat.IO_REPARSE_TAG_SYMLINK)
+
+ def copyfile(source, target, follow_symlinks):
"""
Copy from one file to another using CopyFile2 (Windows only).
"""
- _winapi.CopyFile2(source, target, 0)
+ if follow_symlinks:
+ flags = 0
+ else:
+ flags = _winapi.COPY_FILE_COPY_SYMLINK
+ try:
+ _winapi.CopyFile2(source, target, flags)
+ return
+ except OSError as err:
+ # Check for ERROR_ACCESS_DENIED
+ if err.winerror != 5 or not _is_dirlink(source):
+ raise
+ flags |= _winapi.COPY_FILE_DIRECTORY
+ _winapi.CopyFile2(source, target, flags)
else:
copyfile = None
diff --git a/Lib/test/test_pathlib/test_pathlib_abc.py
b/Lib/test/test_pathlib/test_pathlib_abc.py
index 1c959056c16ca3..cd629c01871165 100644
--- a/Lib/test/test_pathlib/test_pathlib_abc.py
+++ b/Lib/test/test_pathlib/test_pathlib_abc.py
@@ -1743,7 +1743,7 @@ def test_copy_directory(self):
source.copy(target)
@needs_symlinks
- def test_copy_symlink(self):
+ def test_copy_symlink_follow_symlinks_true(self):
base = self.cls(self.base)
source = base / 'linkA'
target = base / 'copyA'
@@ -1752,6 +1752,26 @@ def test_copy_symlink(self):
self.assertFalse(target.is_symlink())
self.assertEqual(source.read_text(), target.read_text())
+ @needs_symlinks
+ def test_copy_symlink_follow_symlinks_false(self):
+ base = self.cls(self.base)
+ source = base / 'linkA'
+ target = base / 'copyA'
+ source.copy(target, follow_symlinks=False)
+ self.assertTrue(target.exists())
+ self.assertTrue(target.is_symlink())
+ self.assertEqual(source.readlink(), target.readlink())
+
+ @needs_symlinks
+ def test_copy_directory_symlink_follow_symlinks_false(self):
+ base = self.cls(self.base)
+ source = base / 'linkB'
+ target = base / 'copyA'
+ source.copy(target, follow_symlinks=False)
+ self.assertTrue(target.exists())
+ self.assertTrue(target.is_symlink())
+ self.assertEqual(source.readlink(), target.readlink())
+
def test_copy_to_existing_file(self):
base = self.cls(self.base)
source = base / 'fileA'
@@ -1780,6 +1800,19 @@ def test_copy_to_existing_symlink(self):
self.assertFalse(real_target.is_symlink())
self.assertEqual(source.read_text(), real_target.read_text())
+ @needs_symlinks
+ def test_copy_to_existing_symlink_follow_symlinks_false(self):
+ base = self.cls(self.base)
+ source = base / 'dirB' / 'fileB'
+ target = base / 'linkA'
+ real_target = base / 'fileA'
+ source.copy(target, follow_symlinks=False)
+ self.assertTrue(target.exists())
+ self.assertTrue(target.is_symlink())
+ self.assertTrue(real_target.exists())
+ self.assertFalse(real_target.is_symlink())
+ self.assertEqual(source.read_text(), real_target.read_text())
+
def test_copy_empty(self):
base = self.cls(self.base)
source = base / 'empty'
diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 8794d568e92a36..c90d6c5a9ef3ef 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -3166,6 +3166,11 @@ static int winapi_exec(PyObject *m)
#define COPY_FILE_REQUEST_COMPRESSED_TRAFFIC 0x10000000
#endif
WINAPI_CONSTANT(F_DWORD, COPY_FILE_REQUEST_COMPRESSED_TRAFFIC);
+#ifndef COPY_FILE_DIRECTORY
+ // Only defined in newer WinSDKs
+ #define COPY_FILE_DIRECTORY 0x00000080
+#endif
+ WINAPI_CONSTANT(F_DWORD, COPY_FILE_DIRECTORY);
WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_CHUNK_STARTED);
WINAPI_CONSTANT(F_DWORD, COPYFILE2_CALLBACK_CHUNK_FINISHED);
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