Fix handling of symlinks to directories on Windows.

python · barneygale · Jun 14, 2024 · May 14, 2024 · May 15, 2024 · May 15, 2024
commit c683c2dfa72330801fa35de355020f1fa7807126
@@ -16,12 +16,9 @@
     import grp
 except ImportError:
     grp = None
-try:
-    import _winapi
-except ImportError:
-    _winapi = None
 
 from ._abc import UnsupportedOperation, PurePathBase, PathBase
+from ._os import copyfile
 
 
 __all__ = [
@@ -784,7 +781,7 @@ def mkdir(self, mode=0o777, parents=False, exist_ok=False):
             if not exist_ok or not self.is_dir():
                 raise
 
-    if hasattr(_winapi, 'CopyFile2'):
+    if copyfile:
         def copy(self, target, follow_symlinks=True):
             """
             Copy the contents of this file to the given target. If this file is a
@@ -799,9 +796,7 @@ def copy(self, target, follow_symlinks=True):
                     # Use generic implementation from PathBase.
                     return PathBase.copy(self, target, follow_symlinks=follow_symlinks)
                 raise
-
-            flags = 0 if follow_symlinks else _winapi.COPY_FILE_COPY_SYMLINK
-            _winapi.CopyFile2(os.fspath(self), target, flags)
+            copyfile(os.fspath(self), target, follow_symlinks)
 
     def chmod(self, mode, *, follow_symlinks=True):
         """

@@ -4,6 +4,7 @@
 
 from errno import EBADF, EOPNOTSUPP, ETXTBSY, EXDEV
 import os
+import stat
 import sys
 try:
     import fcntl
@@ -13,6 +14,10 @@
     import posix
 except ImportError:
     posix = None
+try:
+    import _winapi
+except ImportError:
+    _winapi = None
 
 
 def get_copy_blocksize(infd):
@@ -87,6 +92,35 @@ def copyfd(source_fd, target_fd):
     copyfd = None
 
 
+if _winapi and hasattr(_winapi, 'CopyFile2'):
+    def is_dirlink(path):
+        try:
+            st = os.lstat(path)
+        except OSError:
+            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).
+        """
+        if follow_symlinks:
+            flags = 0
+        else:
+            flags = _winapi.COPY_FILE_COPY_SYMLINK
+            try:
+                _winapi.CopyFile2(source, target, flags)
+            except OSError as err:
+                # Check for ERROR_ACCESS_DENIED
+                if err.winerror != 5 or not is_dirlink(source):
+                    raise err
+            flags |= _winapi.COPY_FILE_DIRECTORY
+        _winapi.CopyFile2(source, target, flags)
+else:
+    copyfile = None
+
+
 def copyfileobj(source_f, target_f):
     """
     Copy data from file-like object source_f to file-like object target_f.