GH-127381: pathlib ABCs: remove `PathBase.unlink()` and `rmdir()` (#127736)

Virtual filesystems don't always make a distinction between deleting files
and empty directories, and sometimes support deleting non-empty directories
in a single operation. Here we remove `PathBase.unlink()` and `rmdir()`,
leaving `_delete()` as the sole deletion method, now made abstract. I hope
to drop the underscore prefix later on.

2 files changed, 18 insertions, 41 deletions

diff --git a/Lib/pathlib/_abc.py b/Lib/pathlib/_abc.py
index 820970f..309eab2 100644
--- a/Lib/pathlib/_abc.py
+++ b/Lib/pathlib/_abc.py
@@ -840,6 +840,12 @@ class PathBase(PurePathBase):
                          dirs_exist_ok=dirs_exist_ok,
                          preserve_metadata=preserve_metadata)
 
+    def _delete(self):
+        """
+        Delete this file or directory (including all sub-directories).
+        """
+        raise UnsupportedOperation(self._unsupported_msg('_delete()'))
+
     def move(self, target):
         """
         Recursively move this file or directory tree to the given destination.
@@ -874,43 +880,6 @@ class PathBase(PurePathBase):
         """
         self.chmod(mode, follow_symlinks=False)
 
-    def unlink(self, missing_ok=False):
-        """
-        Remove this file or link.
-        If the path is a directory, use rmdir() instead.
-        """
-        raise UnsupportedOperation(self._unsupported_msg('unlink()'))
-
-    def rmdir(self):
-        """
-        Remove this directory.  The directory must be empty.
-        """
-        raise UnsupportedOperation(self._unsupported_msg('rmdir()'))
-
-    def _delete(self):
-        """
-        Delete this file or directory (including all sub-directories).
-        """
-        if self.is_symlink() or self.is_junction():
-            self.unlink()
-        elif self.is_dir():
-            self._rmtree()
-        else:
-            self.unlink()
-
-    def _rmtree(self):
-        def on_error(err):
-            raise err
-        results = self.walk(
-            on_error=on_error,
-            top_down=False,  # So we rmdir() empty directories.
-            follow_symlinks=False)
-        for dirpath, _, filenames in results:
-            for filename in filenames:
-                filepath = dirpath / filename
-                filepath.unlink()
-            dirpath.rmdir()
-
     def owner(self, *, follow_symlinks=True):
         """
         Return the login name of the file owner.
diff --git a/Lib/pathlib/_local.py b/Lib/pathlib/_local.py
index 250bc12..f87069c 100644
--- a/Lib/pathlib/_local.py
+++ b/Lib/pathlib/_local.py
@@ -846,10 +846,18 @@ class Path(PathBase, PurePath):
         """
         os.rmdir(self)
 
-    def _rmtree(self):
-        # Lazy import to improve module import time
-        import shutil
-        shutil.rmtree(self)
+    def _delete(self):
+        """
+        Delete this file or directory (including all sub-directories).
+        """
+        if self.is_symlink() or self.is_junction():
+            self.unlink()
+        elif self.is_dir():
+            # Lazy import to improve module import time
+            import shutil
+            shutil.rmtree(self)
+        else:
+            self.unlink()
 
     def rename(self, target):
         """