From 86700a7f048f3e8f837928155548cfcf142c7018 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Wed, 29 Nov 2023 23:25:04 +0100
Subject: [PATCH 01/12] DEPR: Deprecate dtype inference on pandas objects

---
 doc/source/whatsnew/v2.2.0.rst                  |  1 +
 pandas/core/frame.py                            | 15 +++++++++++++++
 pandas/core/indexes/base.py                     | 15 ++++++++++++++-
 pandas/core/series.py                           | 15 +++++++++++++++
 pandas/tests/copy_view/test_constructors.py     |  3 ++-
 pandas/tests/frame/test_constructors.py         | 17 +++++++++++++++++
 .../indexes/base_class/test_constructors.py     | 14 ++++++++++++++
 pandas/tests/indexes/test_base.py               |  3 ++-
 .../tests/series/accessors/test_dt_accessor.py  |  7 ++++---
 pandas/tests/series/methods/test_between.py     |  2 +-
 pandas/tests/series/methods/test_equals.py      |  6 ++++--
 pandas/tests/series/test_constructors.py        | 17 ++++++++++++++++-
 12 files changed, 105 insertions(+), 10 deletions(-)

diff --git a/doc/source/whatsnew/v2.2.0.rst b/doc/source/whatsnew/v2.2.0.rst
index 8cb4b3f24d435..ca380340b7d1d 100644
--- a/doc/source/whatsnew/v2.2.0.rst
+++ b/doc/source/whatsnew/v2.2.0.rst
@@ -384,6 +384,7 @@ Other Deprecations
 - Deprecated allowing passing :class:`BlockManager` objects to :class:`DataFrame` or :class:`SingleBlockManager` objects to :class:`Series` (:issue:`52419`)
 - Deprecated automatic downcasting of object-dtype results in :meth:`Series.replace` and :meth:`DataFrame.replace`, explicitly call ``result = result.infer_objects(copy=False)`` instead. To opt in to the future version, use ``pd.set_option("future.no_silent_downcasting", True)`` (:issue:`54710`)
 - Deprecated downcasting behavior in :meth:`Series.where`, :meth:`DataFrame.where`, :meth:`Series.mask`, :meth:`DataFrame.mask`, :meth:`Series.clip`, :meth:`DataFrame.clip`; in a future version these will not infer object-dtype columns to non-object dtype, or all-round floats to integer dtype. Call ``result.infer_objects(copy=False)`` on the result for object inference, or explicitly cast floats to ints. To opt in to the future version, use ``pd.set_option("future.no_silent_downcasting", True)`` (:issue:`53656`)
+- Deprecated dtype inference in :class:`Index`, :class:`Series` and :class:`DataFrame` constructors when giving a pandas input, call ``.infer_objects`` on the input to keep the current behavior (:issue:`56012`)
 - Deprecated including the groups in computations when using :meth:`DataFrameGroupBy.apply` and :meth:`DataFrameGroupBy.resample`; pass ``include_groups=False`` to exclude the groups (:issue:`7155`)
 - Deprecated indexing an :class:`Index`  with a boolean indexer of length zero (:issue:`55820`)
 - Deprecated not passing a tuple to :class:`DataFrameGroupBy.get_group` or :class:`SeriesGroupBy.get_group` when grouping by a length-1 list-like (:issue:`25971`)
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index f6c44827d1662..bc15a340695d1 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -714,6 +714,10 @@ def __init__(
 
         manager = _get_option("mode.data_manager", silent=True)
 
+        is_pandas_object = isinstance(data, (Series, Index, ExtensionArray))
+        data_dtype = getattr(data, "dtype", None)
+        original_dtype = dtype
+
         # GH47215
         if isinstance(index, set):
             raise ValueError("index cannot be a set")
@@ -900,6 +904,17 @@ def __init__(
 
         NDFrame.__init__(self, mgr)
 
+        if original_dtype is None and is_pandas_object and data_dtype == np.object_:
+            if self.dtypes.iloc[0] != data_dtype:
+                warnings.warn(
+                    "Dtype inference on a pandas object "
+                    "(Series, Index, ExtensionArray) is deprecated. The Index "
+                    "constructor will keep the original dtype in the future. "
+                    "Call ``infer_objects on the result",
+                    FutureWarning,
+                    stacklevel=2,
+                )
+
     # ----------------------------------------------------------------------
 
     def __dataframe__(
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index ac4d2976593a2..e508a6b1dd996 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -491,6 +491,8 @@ def __new__(
         if not copy and isinstance(data, (ABCSeries, Index)):
             refs = data._references
 
+        is_pandas_object = isinstance(data, (ABCSeries, Index, ExtensionArray))
+
         # range
         if isinstance(data, (range, RangeIndex)):
             result = RangeIndex(start=data, copy=copy, name=name)
@@ -570,7 +572,18 @@ def __new__(
         klass = cls._dtype_to_subclass(arr.dtype)
 
         arr = klass._ensure_array(arr, arr.dtype, copy=False)
-        return klass._simple_new(arr, name, refs=refs)
+        result = klass._simple_new(arr, name, refs=refs)
+        if dtype is None and is_pandas_object and data_dtype == np.object_:
+            if result.dtype != data_dtype:
+                warnings.warn(
+                    "Dtype inference on a pandas object "
+                    "(Series, Index, ExtensionArray) is deprecated. The Index "
+                    "constructor will keep the original dtype in the future. "
+                    "Call ``infer_objects on the result",
+                    FutureWarning,
+                    stacklevel=2,
+                )
+        return result
 
     @classmethod
     def _ensure_array(cls, data, dtype, copy: bool):
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 888e8cc4e7d40..e4fbfd9ce6ce8 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -424,6 +424,10 @@ def __init__(
                 self.name = name
             return
 
+        is_pandas_object = isinstance(data, (Series, Index, ExtensionArray))
+        data_dtype = getattr(data, "dtype", None)
+        original_dtype = dtype
+
         if isinstance(data, (ExtensionArray, np.ndarray)):
             if copy is not False and using_copy_on_write():
                 if dtype is None or astype_is_view(data.dtype, pandas_dtype(dtype)):
@@ -581,6 +585,17 @@ def __init__(
         self.name = name
         self._set_axis(0, index)
 
+        if original_dtype is None and is_pandas_object and data_dtype == np.object_:
+            if self.dtype != data_dtype:
+                warnings.warn(
+                    "Dtype inference on a pandas object "
+                    "(Series, Index, ExtensionArray) is deprecated. The Index "
+                    "constructor will keep the original dtype in the future. "
+                    "Call ``infer_objects on the result",
+                    FutureWarning,
+                    stacklevel=2,
+                )
+
     def _init_dict(
         self, data, index: Index | None = None, dtype: DtypeObj | None = None
     ):
diff --git a/pandas/tests/copy_view/test_constructors.py b/pandas/tests/copy_view/test_constructors.py
index 7d5c485958039..1aa458a625028 100644
--- a/pandas/tests/copy_view/test_constructors.py
+++ b/pandas/tests/copy_view/test_constructors.py
@@ -314,7 +314,8 @@ def test_dataframe_from_series_or_index_different_dtype(using_copy_on_write, con
 
 def test_dataframe_from_series_infer_datetime(using_copy_on_write):
     ser = Series([Timestamp("2019-12-31"), Timestamp("2020-12-31")], dtype=object)
-    df = DataFrame(ser)
+    with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+        df = DataFrame(ser)
     assert not np.shares_memory(get_array(ser), get_array(df, 0))
     if using_copy_on_write:
         assert df._mgr._has_no_reference(0)
diff --git a/pandas/tests/frame/test_constructors.py b/pandas/tests/frame/test_constructors.py
index 84189f8149d81..081d0ad15de67 100644
--- a/pandas/tests/frame/test_constructors.py
+++ b/pandas/tests/frame/test_constructors.py
@@ -2759,6 +2759,23 @@ def test_frame_string_inference_block_dim(self):
             df = DataFrame(np.array([["hello", "goodbye"], ["hello", "Hello"]]))
         assert df._mgr.blocks[0].ndim == 2
 
+    def test_inference_on_pandas_objects(self):
+        # GH#56012
+        idx = Index([Timestamp("2019-12-31")], dtype=object)
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = DataFrame(idx, columns=["a"])
+        assert result.dtypes.iloc[0] != np.object_
+        result = DataFrame({"a": idx})
+        assert result.dtypes.iloc[0] == np.object_
+
+        ser = Series([Timestamp("2019-12-31")], dtype=object)
+
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = DataFrame(ser, columns=["a"])
+        assert result.dtypes.iloc[0] != np.object_
+        result = DataFrame({"a": ser})
+        assert result.dtypes.iloc[0] == np.object_
+
 
 class TestDataFrameConstructorIndexInference:
     def test_frame_from_dict_of_series_overlapping_monthly_period_indexes(self):
diff --git a/pandas/tests/indexes/base_class/test_constructors.py b/pandas/tests/indexes/base_class/test_constructors.py
index 60abbfc441e8e..fd5176a28565e 100644
--- a/pandas/tests/indexes/base_class/test_constructors.py
+++ b/pandas/tests/indexes/base_class/test_constructors.py
@@ -5,6 +5,7 @@
 from pandas import (
     Index,
     MultiIndex,
+    Series,
 )
 import pandas._testing as tm
 
@@ -57,3 +58,16 @@ def test_index_string_inference(self):
         with pd.option_context("future.infer_string", True):
             ser = Index(["a", 1])
         tm.assert_index_equal(ser, expected)
+
+    def test_inference_on_pandas_objects(self):
+        # GH#56012
+        idx = Index([pd.Timestamp("2019-12-31")], dtype=object)
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = Index(idx)
+        assert result.dtype != np.object_
+
+        ser = Series([pd.Timestamp("2019-12-31")], dtype=object)
+
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = Index(ser)
+        assert result.dtype != np.object_
diff --git a/pandas/tests/indexes/test_base.py b/pandas/tests/indexes/test_base.py
index 3db81c0285bd2..421ae102b8b12 100644
--- a/pandas/tests/indexes/test_base.py
+++ b/pandas/tests/indexes/test_base.py
@@ -99,7 +99,8 @@ def test_constructor_copy(self, index):
     )
     def test_constructor_from_index_dtlike(self, cast_as_obj, index):
         if cast_as_obj:
-            result = Index(index.astype(object))
+            with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+                result = Index(index.astype(object))
         else:
             result = Index(index)
 
diff --git a/pandas/tests/series/accessors/test_dt_accessor.py b/pandas/tests/series/accessors/test_dt_accessor.py
index 083a4c4b24adb..fa882cb9a61a0 100644
--- a/pandas/tests/series/accessors/test_dt_accessor.py
+++ b/pandas/tests/series/accessors/test_dt_accessor.py
@@ -259,9 +259,10 @@ def test_dt_accessor_limited_display_api(self):
         tm.assert_almost_equal(results, sorted(set(ok_for_dt + ok_for_dt_methods)))
 
         # Period
-        ser = Series(
-            period_range("20130101", periods=5, freq="D", name="xxx").astype(object)
-        )
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            ser = Series(
+                period_range("20130101", periods=5, freq="D", name="xxx").astype(object)
+            )
         results = get_dir(ser)
         tm.assert_almost_equal(
             results, sorted(set(ok_for_period + ok_for_period_methods))
diff --git a/pandas/tests/series/methods/test_between.py b/pandas/tests/series/methods/test_between.py
index 8f4931beae589..005272b97e19a 100644
--- a/pandas/tests/series/methods/test_between.py
+++ b/pandas/tests/series/methods/test_between.py
@@ -20,7 +20,7 @@ def test_between(self):
         tm.assert_series_equal(result, expected)
 
     def test_between_datetime_object_dtype(self):
-        ser = Series(bdate_range("1/1/2000", periods=20).astype(object))
+        ser = Series(bdate_range("1/1/2000", periods=20).astype(object), dtype=object)
         ser[::2] = np.nan
 
         result = ser[ser.between(ser[3], ser[17])]
diff --git a/pandas/tests/series/methods/test_equals.py b/pandas/tests/series/methods/test_equals.py
index b94723b7cbddf..875ffdd3fe851 100644
--- a/pandas/tests/series/methods/test_equals.py
+++ b/pandas/tests/series/methods/test_equals.py
@@ -82,13 +82,15 @@ def test_equals_matching_nas():
     left = Series([np.datetime64("NaT")], dtype=object)
     right = Series([np.datetime64("NaT")], dtype=object)
     assert left.equals(right)
-    assert Index(left).equals(Index(right))
+    with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+        assert Index(left).equals(Index(right))
     assert left.array.equals(right.array)
 
     left = Series([np.timedelta64("NaT")], dtype=object)
     right = Series([np.timedelta64("NaT")], dtype=object)
     assert left.equals(right)
-    assert Index(left).equals(Index(right))
+    with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+        assert Index(left).equals(Index(right))
     assert left.array.equals(right.array)
 
     left = Series([np.float64("NaN")], dtype=object)
diff --git a/pandas/tests/series/test_constructors.py b/pandas/tests/series/test_constructors.py
index e08f8d0c15f39..69f62199d048e 100644
--- a/pandas/tests/series/test_constructors.py
+++ b/pandas/tests/series/test_constructors.py
@@ -1323,7 +1323,8 @@ def test_constructor_periodindex(self):
         pi = period_range("20130101", periods=5, freq="D")
         s = Series(pi)
         assert s.dtype == "Period[D]"
-        expected = Series(pi.astype(object))
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            expected = Series(pi.astype(object))
         tm.assert_series_equal(s, expected)
 
     def test_constructor_dict(self):
@@ -2144,6 +2145,20 @@ def test_series_string_inference_na_first(self):
             result = Series([pd.NA, "b"])
         tm.assert_series_equal(result, expected)
 
+    def test_inference_on_pandas_objects(self):
+        # GH#56012
+        ser = Series([Timestamp("2019-12-31")], dtype=object)
+        with tm.assert_produces_warning(None):
+            # This doesn't do inference
+            result = Series(ser)
+        assert result.dtype == np.object_
+
+        idx = Index([Timestamp("2019-12-31")], dtype=object)
+
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = Series(idx)
+        assert result.dtype != np.object_
+
 
 class TestSeriesConstructorIndexCoercion:
     def test_series_constructor_datetimelike_index_coercion(self):

From 7daf53571cf6268dfd87e50d2dc64f08ce716fea Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 30 Nov 2023 00:17:58 +0100
Subject: [PATCH 02/12] Fixup tests

---
 pandas/_testing/__init__.py                        | 13 ++++++++++---
 pandas/tests/tseries/frequencies/test_inference.py |  4 +++-
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/pandas/_testing/__init__.py b/pandas/_testing/__init__.py
index b1918e1b1d7c2..3a1aae47c5eba 100644
--- a/pandas/_testing/__init__.py
+++ b/pandas/_testing/__init__.py
@@ -15,6 +15,7 @@
     ContextManager,
     cast,
 )
+import warnings
 
 import numpy as np
 
@@ -306,11 +307,17 @@ def box_expected(expected, box_cls, transpose: bool = True):
         else:
             expected = pd.array(expected, copy=False)
     elif box_cls is Index:
-        expected = Index(expected)
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", "Dtype inference", category=FutureWarning)
+            expected = Index(expected)
     elif box_cls is Series:
-        expected = Series(expected)
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", "Dtype inference", category=FutureWarning)
+            expected = Series(expected)
     elif box_cls is DataFrame:
-        expected = Series(expected).to_frame()
+        with warnings.catch_warnings():
+            warnings.filterwarnings("ignore", "Dtype inference", category=FutureWarning)
+            expected = Series(expected).to_frame()
         if transpose:
             # for vector operations, we need a DataFrame to be a single-row,
             #  not a single-column, in order to operate against non-DataFrame
diff --git a/pandas/tests/tseries/frequencies/test_inference.py b/pandas/tests/tseries/frequencies/test_inference.py
index 45741e852fef7..99a504f4188c1 100644
--- a/pandas/tests/tseries/frequencies/test_inference.py
+++ b/pandas/tests/tseries/frequencies/test_inference.py
@@ -23,6 +23,7 @@
     date_range,
     period_range,
 )
+import pandas._testing as tm
 from pandas.core.arrays import (
     DatetimeArray,
     TimedeltaArray,
@@ -206,7 +207,8 @@ def test_infer_freq_custom(base_delta_code_pair, constructor):
 )
 def test_infer_freq_index(freq, expected):
     rng = period_range("1959Q2", "2009Q3", freq=freq)
-    rng = Index(rng.to_timestamp("D", how="e").astype(object))
+    with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+        rng = Index(rng.to_timestamp("D", how="e").astype(object))
 
     assert rng.inferred_freq == expected
 

From 2b28aa29605527f6531fc33002383427b2a8cb7c Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 30 Nov 2023 10:52:01 +0100
Subject: [PATCH 03/12] Update base.py

---
 pandas/core/indexes/base.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index e508a6b1dd996..342cd9675f244 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -583,7 +583,7 @@ def __new__(
                     FutureWarning,
                     stacklevel=2,
                 )
-        return result
+        return result  # type: ignore[return-value]
 
     @classmethod
     def _ensure_array(cls, data, dtype, copy: bool):

From 1c6c3e3a930c0db92294445c25f213efb6ec1fe7 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <patrick_hoefler@gmx.net>
Date: Sat, 9 Dec 2023 23:55:10 +0100
Subject: [PATCH 04/12] Fixup

---
 pandas/core/strings/accessor.py  | 11 +++++------
 pandas/tests/strings/test_cat.py | 21 ++++++++++++++++-----
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/pandas/core/strings/accessor.py b/pandas/core/strings/accessor.py
index 75866c6f6013a..631030d637fae 100644
--- a/pandas/core/strings/accessor.py
+++ b/pandas/core/strings/accessor.py
@@ -689,19 +689,18 @@ def cat(
             result = cat_safe(all_cols, sep)
 
         out: Index | Series
+        if isinstance(self._orig.dtype, CategoricalDtype):
+            # We need to infer the new categories.
+            dtype = self._orig.dtype.categories.dtype  # type: ignore[assignment]
+        else:
+            dtype = self._orig.dtype
         if isinstance(self._orig, ABCIndex):
             # add dtype for case that result is all-NA
-            dtype = None
             if isna(result).all():
                 dtype = object
 
             out = Index(result, dtype=dtype, name=self._orig.name)
         else:  # Series
-            if isinstance(self._orig.dtype, CategoricalDtype):
-                # We need to infer the new categories.
-                dtype = self._orig.dtype.categories.dtype  # type: ignore[assignment]
-            else:
-                dtype = self._orig.dtype
             res_ser = Series(
                 result, dtype=dtype, index=data.index, name=self._orig.name, copy=False
             )
diff --git a/pandas/tests/strings/test_cat.py b/pandas/tests/strings/test_cat.py
index 284932491a65e..c1e7ad6e02779 100644
--- a/pandas/tests/strings/test_cat.py
+++ b/pandas/tests/strings/test_cat.py
@@ -98,14 +98,18 @@ def test_str_cat_categorical(
 
     with option_context("future.infer_string", infer_string):
         s = Index(["a", "a", "b", "a"], dtype=dtype_caller)
-        s = s if box == Index else Series(s, index=s)
+        s = s if box == Index else Series(s, index=s, dtype=s.dtype)
         t = Index(["b", "a", "b", "c"], dtype=dtype_target)
 
-        expected = Index(["ab", "aa", "bb", "ac"])
+        expected = Index(
+            ["ab", "aa", "bb", "ac"], dtype=object if dtype_caller == "object" else None
+        )
         expected = (
             expected
             if box == Index
-            else Series(expected, index=Index(s, dtype=dtype_caller))
+            else Series(
+                expected, index=Index(s, dtype=dtype_caller), dtype=expected.dtype
+            )
         )
 
         # Series/Index with unaligned Index -> t.values
@@ -123,12 +127,19 @@ def test_str_cat_categorical(
 
         # Series/Index with Series having different Index
         t = Series(t.values, index=t.values)
-        expected = Index(["aa", "aa", "bb", "bb", "aa"])
+        expected = Index(
+            ["aa", "aa", "bb", "bb", "aa"],
+            dtype=object if dtype_caller == "object" else None,
+        )
         dtype = object if dtype_caller == "object" else s.dtype.categories.dtype
         expected = (
             expected
             if box == Index
-            else Series(expected, index=Index(expected.str[:1], dtype=dtype))
+            else Series(
+                expected,
+                index=Index(expected.str[:1], dtype=dtype),
+                dtype=expected.dtype,
+            )
         )
 
         result = s.str.cat(t, sep=sep)

From 5a6244c4ac77cc082f66785856186e971e894c0b Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 14 Dec 2023 22:39:16 +0100
Subject: [PATCH 05/12] Update accessor.py

---
 pandas/core/strings/accessor.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/strings/accessor.py b/pandas/core/strings/accessor.py
index 631030d637fae..1b7d632c0fa80 100644
--- a/pandas/core/strings/accessor.py
+++ b/pandas/core/strings/accessor.py
@@ -691,13 +691,13 @@ def cat(
         out: Index | Series
         if isinstance(self._orig.dtype, CategoricalDtype):
             # We need to infer the new categories.
-            dtype = self._orig.dtype.categories.dtype  # type: ignore[assignment]
+            dtype = self._orig.dtype.categories.dtype
         else:
             dtype = self._orig.dtype
         if isinstance(self._orig, ABCIndex):
             # add dtype for case that result is all-NA
             if isna(result).all():
-                dtype = object
+                dtype = object  # type: ignore[assignment]
 
             out = Index(result, dtype=dtype, name=self._orig.name)
         else:  # Series

From 24eff8007fc2e8d2d9ac2c23c37741391623db8d Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Mon, 18 Dec 2023 20:30:43 +0100
Subject: [PATCH 06/12] Update pandas/core/indexes/base.py

Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
---
 pandas/core/indexes/base.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 50b0fcfd6dc21..f994b1057ee44 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -580,7 +580,7 @@ def __new__(
                     "Dtype inference on a pandas object "
                     "(Series, Index, ExtensionArray) is deprecated. The Index "
                     "constructor will keep the original dtype in the future. "
-                    "Call ``infer_objects on the result",
+                    "Call `infer_objects` on the result",
                     FutureWarning,
                     stacklevel=2,
                 )

From eef58ea3ad18f282521686e08f85a5345ad57e82 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Mon, 18 Dec 2023 20:30:48 +0100
Subject: [PATCH 07/12] Update pandas/core/frame.py

Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
---
 pandas/core/frame.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 638662a690775..6dcbe10618d26 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -922,7 +922,7 @@ def __init__(
                     "Dtype inference on a pandas object "
                     "(Series, Index, ExtensionArray) is deprecated. The Index "
                     "constructor will keep the original dtype in the future. "
-                    "Call ``infer_objects on the result",
+                    "Call `infer_objects` on the result",
                     FutureWarning,
                     stacklevel=2,
                 )

From ab2a735558030e1d67e059951a58e789fc641697 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Mon, 18 Dec 2023 20:31:01 +0100
Subject: [PATCH 08/12] Update pandas/core/series.py

Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
---
 pandas/core/series.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index a322b02fc50c9..c79309867cb28 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -591,7 +591,7 @@ def __init__(
                     "Dtype inference on a pandas object "
                     "(Series, Index, ExtensionArray) is deprecated. The Index "
                     "constructor will keep the original dtype in the future. "
-                    "Call ``infer_objects on the result",
+                    "Call `infer_objects` on the result",
                     FutureWarning,
                     stacklevel=2,
                 )

From ab62a3196169899ccff239a978f22032dacea964 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Mon, 18 Dec 2023 21:02:35 +0100
Subject: [PATCH 09/12] Update series.py

---
 pandas/core/series.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/series.py b/pandas/core/series.py
index c79309867cb28..9af3d63fa1081 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -593,7 +593,7 @@ def __init__(
                     "constructor will keep the original dtype in the future. "
                     "Call `infer_objects` on the result",
                     FutureWarning,
-                    stacklevel=2,
+                    stacklevel=find_stack_level(),
                 )
 
     def _init_dict(

From 0e828b72b891944447387ddc7215c8c35f37d41f Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 21 Dec 2023 19:47:11 +0100
Subject: [PATCH 10/12] Update

---
 pandas/core/frame.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 6dcbe10618d26..e1048a51089ac 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -920,9 +920,10 @@ def __init__(
             if self.dtypes.iloc[0] != data_dtype:
                 warnings.warn(
                     "Dtype inference on a pandas object "
-                    "(Series, Index, ExtensionArray) is deprecated. The Index "
+                    "(Series, Index, ExtensionArray) is deprecated. The DataFrame "
                     "constructor will keep the original dtype in the future. "
-                    "Call `infer_objects` on the result",
+                    "Call `infer_objects` on the result to get the old "
+                    "behavior.",
                     FutureWarning,
                     stacklevel=2,
                 )

From 86f1a946001b0e09f088ce79d47743f718eac5a3 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 21 Dec 2023 19:51:21 +0100
Subject: [PATCH 11/12] Address comments

---
 pandas/core/indexes/base.py | 3 ++-
 pandas/core/series.py       | 4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index f994b1057ee44..e01c4e75e9f8a 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -580,7 +580,8 @@ def __new__(
                     "Dtype inference on a pandas object "
                     "(Series, Index, ExtensionArray) is deprecated. The Index "
                     "constructor will keep the original dtype in the future. "
-                    "Call `infer_objects` on the result",
+                    "Call `infer_objects` on the result to get the old "
+                    "behavior.",
                     FutureWarning,
                     stacklevel=2,
                 )
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 9af3d63fa1081..d46068b6338c5 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -589,9 +589,9 @@ def __init__(
             if self.dtype != data_dtype:
                 warnings.warn(
                     "Dtype inference on a pandas object "
-                    "(Series, Index, ExtensionArray) is deprecated. The Index "
+                    "(Series, Index, ExtensionArray) is deprecated. The Series "
                     "constructor will keep the original dtype in the future. "
-                    "Call `infer_objects` on the result",
+                    "Call `infer_objects` on the result to get the old behavior.",
                     FutureWarning,
                     stacklevel=find_stack_level(),
                 )

From cd067cc8b6f9fa4424e9086459bad1b2f1560e7b Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Thu, 21 Dec 2023 22:44:27 +0100
Subject: [PATCH 12/12] Address comments

---
 pandas/tests/series/accessors/test_dt_accessor.py | 5 ++---
 pandas/tests/series/methods/test_between.py       | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/series/accessors/test_dt_accessor.py b/pandas/tests/series/accessors/test_dt_accessor.py
index fa882cb9a61a0..34465a7c12c18 100644
--- a/pandas/tests/series/accessors/test_dt_accessor.py
+++ b/pandas/tests/series/accessors/test_dt_accessor.py
@@ -259,10 +259,9 @@ def test_dt_accessor_limited_display_api(self):
         tm.assert_almost_equal(results, sorted(set(ok_for_dt + ok_for_dt_methods)))
 
         # Period
+        idx = period_range("20130101", periods=5, freq="D", name="xxx").astype(object)
         with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
-            ser = Series(
-                period_range("20130101", periods=5, freq="D", name="xxx").astype(object)
-            )
+            ser = Series(idx)
         results = get_dir(ser)
         tm.assert_almost_equal(
             results, sorted(set(ok_for_period + ok_for_period_methods))
diff --git a/pandas/tests/series/methods/test_between.py b/pandas/tests/series/methods/test_between.py
index 005272b97e19a..3913419038876 100644
--- a/pandas/tests/series/methods/test_between.py
+++ b/pandas/tests/series/methods/test_between.py
@@ -20,7 +20,7 @@ def test_between(self):
         tm.assert_series_equal(result, expected)
 
     def test_between_datetime_object_dtype(self):
-        ser = Series(bdate_range("1/1/2000", periods=20).astype(object), dtype=object)
+        ser = Series(bdate_range("1/1/2000", periods=20), dtype=object)
         ser[::2] = np.nan
 
         result = ser[ser.between(ser[3], ser[17])]