Restore the working directory after nested Path contexts

newsfragments/+reentrant-context.bugfix.rst

@@ -0,0 +1 @@
+Nested use of the same ``Path`` as a context manager now restores the original working directory.

path/__init__.py

@@ -243,12 +243,14 @@ def __rtruediv__(self, rel: str) -> Self:
         return self._next_class(self.module.join(rel, self))
 
     def __enter__(self) -> Self:
-        self._old_dir = self.cwd()
+        old_dir = self.cwd()
         os.chdir(self)
+        self._old_dirs = getattr(self, '_old_dirs', [])
+        self._old_dirs.append(old_dir)
         return self
 
     def __exit__(self, *_) -> None:
-        os.chdir(self._old_dir)
+        os.chdir(self._old_dirs.pop())
 
     @classmethod
     def cwd(cls):

tests/test_path.py

@@ -471,6 +471,22 @@ def test_context_manager(self, tmpdir):
             assert os.getcwd() == os.path.realpath(subdir)
         assert os.getcwd() == old_dir
 
+    @pytest.mark.parametrize('raise_inside', [False, True])
+    def test_reentrant_context_manager(self, tmpdir, raise_inside):
+        directory = Path(tmpdir)
+        old_dir = os.getcwd()
+        try:
+            with directory:
+                with contextlib.suppress(ValueError):
+                    with directory:
+                        assert Path.cwd() == directory.realpath()
+                        if raise_inside:
+                            raise ValueError('inner context')
+                assert Path.cwd() == directory.realpath()
+            assert os.getcwd() == old_dir
+        finally:
+            os.chdir(old_dir)
+
     def test_touch(self, tmpdir):
         # NOTE: This test takes a long time to run (~10 seconds).
         # It sleeps several seconds because on Windows, the resolution