From 2e88e7c22d0d71681cef13ac89e706882cae1fb5 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 7 Dec 2023 21:05:12 +0100
Subject: [PATCH] BUG: reset_index not preserving object dtype for string
 option (#56160)

* BUG: reset_index not preserving object dtype for string option

* Fixup

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

(cherry picked from commit 5e0df27fadfeb29e76336b527f4c01cd2f575136)
---
 doc/source/whatsnew/v2.1.4.rst                  | 2 ++
 pandas/core/series.py                           | 2 +-
 pandas/tests/series/methods/test_reset_index.py | 9 +++++++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v2.1.4.rst b/doc/source/whatsnew/v2.1.4.rst
index 26fd23d80208c..13df35a1477d0 100644
--- a/doc/source/whatsnew/v2.1.4.rst
+++ b/doc/source/whatsnew/v2.1.4.rst
@@ -31,6 +31,8 @@ Bug fixes
 - Fixed bug in :meth:`DataFrame.to_hdf` raising when columns have ``StringDtype`` (:issue:`55088`)
 - Fixed bug in :meth:`Index.insert` casting object-dtype to PyArrow backed strings when ``infer_string`` option is set (:issue:`55638`)
 - Fixed bug in :meth:`Series.__ne__` resulting in False for comparison between ``NA`` and string value for ``dtype="string[pyarrow_numpy]"`` (:issue:`56122`)
+- Fixed bug in :meth:`Series.mode` not keeping object dtype when ``infer_string`` is set (:issue:`56183`)
+- Fixed bug in :meth:`Series.reset_index` not preserving object dtype when ``infer_string`` is set (:issue:`56160`)
 - Fixed bug in :meth:`Series.str.split` and :meth:`Series.str.rsplit` when ``pat=None`` for :class:`ArrowDtype` with ``pyarrow.string`` (:issue:`56271`)
 - Fixed bug in :meth:`Series.str.translate` losing object dtype when string option is set (:issue:`56152`)
 -
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 7b22d89bfe22d..3218d15d8782a 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1652,7 +1652,7 @@ def reset_index(
                 return new_ser.__finalize__(self, method="reset_index")
             else:
                 return self._constructor(
-                    self._values.copy(), index=new_index, copy=False
+                    self._values.copy(), index=new_index, copy=False, dtype=self.dtype
                 ).__finalize__(self, method="reset_index")
         elif inplace:
             raise TypeError(
diff --git a/pandas/tests/series/methods/test_reset_index.py b/pandas/tests/series/methods/test_reset_index.py
index db36221d8f510..272c6663a8dbd 100644
--- a/pandas/tests/series/methods/test_reset_index.py
+++ b/pandas/tests/series/methods/test_reset_index.py
@@ -11,6 +11,7 @@
     RangeIndex,
     Series,
     date_range,
+    option_context,
 )
 import pandas._testing as tm
 
@@ -155,6 +156,14 @@ def test_reset_index_inplace_and_drop_ignore_name(self):
         expected = Series(range(2), name="old")
         tm.assert_series_equal(ser, expected)
 
+    def test_reset_index_drop_infer_string(self):
+        # GH#56160
+        pytest.importorskip("pyarrow")
+        ser = Series(["a", "b", "c"], dtype=object)
+        with option_context("future.infer_string", True):
+            result = ser.reset_index(drop=True)
+        tm.assert_series_equal(result, ser)
+
 
 @pytest.mark.parametrize(
     "array, dtype",