From 5071e1196d741ce7bd54cf13a45e7ea075e57d6f Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Wed, 29 Oct 2025 20:42:44 -0400
Subject: [PATCH 01/16] When finding the common type, return the original type
 if there is only one common type. Return objects for date32 and date64 types
 when converting those types to numpy types.

---
 pandas/core/dtypes/common.py                   |  5 +++++
 pandas/core/dtypes/dtypes.py                   | 18 ++++++++++++++++++
 .../tests/dtypes/cast/test_find_common_type.py | 16 ++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/pandas/core/dtypes/common.py b/pandas/core/dtypes/common.py
index dd63445266134..16fb90b0eca05 100644
--- a/pandas/core/dtypes/common.py
+++ b/pandas/core/dtypes/common.py
@@ -1872,6 +1872,11 @@ def pandas_dtype(dtype) -> DtypeObj:
             result = result()
         return result
 
+    # try a pyarrow dtype
+    from pandas.core.dtypes.dtypes import ArrowDtype
+    if isinstance(dtype, ArrowDtype):
+        return ArrowDtype(dtype)
+
     # try a numpy dtype
     # raise a consistent TypeError if failed
     try:
diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 2e3d73edcdf4f..7fa6011ee438d 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -2277,6 +2277,12 @@ def name(self) -> str:  # type: ignore[override]
     @cache_readonly
     def numpy_dtype(self) -> np.dtype:
         """Return an instance of the related numpy dtype"""
+        if pa.types.is_date32(self.pyarrow_dtype) or pa.types.is_date64(
+            self.pyarrow_dtype
+        ):
+            # date32 and date64 are pyarrow timestamps but do not have a
+            # corresponding numpy dtype.
+            return np.dtype(object)
         if pa.types.is_timestamp(self.pyarrow_dtype):
             # pa.timestamp(unit).to_pandas_dtype() returns ns units
             # regardless of the pyarrow timestamp units.
@@ -2453,6 +2459,18 @@ def _get_common_dtype(self, dtypes: list[DtypeObj]) -> DtypeObj | None:
 
         null_dtype = type(self)(pa.null())
 
+        # Cover cases where numpy does not have a corresponding dtype, but
+        # only one non-null dtype is received, or all dtypes are null.
+        single_dtype = {
+            dtype
+            for dtype in dtypes
+            if dtype != null_dtype
+        }
+        if len(single_dtype) == 0:
+            return null_dtype
+        if len(single_dtype) == 1:
+            return single_dtype.pop()
+
         new_dtype = find_common_type(
             [
                 dtype.numpy_dtype if isinstance(dtype, ArrowDtype) else dtype
diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index 83ef7382fbe8a..dbce6c6e899b1 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -173,3 +173,19 @@ def test_interval_dtype_with_categorical(dtype):
 
     result = find_common_type([dtype, cat.dtype])
     assert result == dtype
+
+
+@pytest.mark.parametrize(
+    "dtypes,expected",
+    [
+        (
+            ["date32[pyarrow]", "null[pyarrow]"],
+            "date32[day][pyarrow]",
+        ),
+    ],
+)
+def test_pyarrow_dtypes(dtypes, expected):
+    """Test finding common types with pyarrow dtypes not in numpy."""
+    source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
+    result = find_common_type(source_dtypes)
+    assert result == pandas_dtype(expected)
\ No newline at end of file

From 38ba1bdfb21ba4d2ab9df7c8e17f38e3d242e7f8 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Wed, 29 Oct 2025 20:57:19 -0400
Subject: [PATCH 02/16] Add bug to changelog

---
 doc/source/whatsnew/v3.0.0.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 2b35abd45a96f..3b7b7863ab722 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -1036,6 +1036,7 @@ Conversion
 - Bug in :meth:`Series.convert_dtypes` and :meth:`DataFrame.convert_dtypes` removing timezone information for objects with :class:`ArrowDtype` (:issue:`60237`)
 - Bug in :meth:`Series.reindex` not maintaining ``float32`` type when a ``reindex`` introduces a missing value (:issue:`45857`)
 - Bug in :meth:`to_datetime` and :meth:`to_timedelta` with input ``None`` returning ``None`` instead of ``NaT``, inconsistent with other conversion methods (:issue:`23055`)
+- Bug in :meth:`ArrowDtype._get_common_dtype` and :meth:`ExtentionDtype._get_common_dtype` when using ``date32[pyarrow]`` and ``date64[pyarrow]`` types (:issue:`62343`)
 
 Strings
 ^^^^^^^

From 4b0a90c56fd43fc8a4f4fa2ba5e9141c1ddc37ab Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 12:55:11 -0500
Subject: [PATCH 03/16] change pyarrow dtype of date32 and date64 to day and ms
 granularity

---
 pandas/core/dtypes/common.py |  5 -----
 pandas/core/dtypes/dtypes.py | 30 ++++++++++++------------------
 2 files changed, 12 insertions(+), 23 deletions(-)

diff --git a/pandas/core/dtypes/common.py b/pandas/core/dtypes/common.py
index 1b68df22583e4..bb3e8105d5472 100644
--- a/pandas/core/dtypes/common.py
+++ b/pandas/core/dtypes/common.py
@@ -1872,11 +1872,6 @@ def pandas_dtype(dtype) -> DtypeObj:
             result = result()
         return result
 
-    # try a pyarrow dtype
-    from pandas.core.dtypes.dtypes import ArrowDtype
-    if isinstance(dtype, ArrowDtype):
-        return ArrowDtype(dtype)
-
     # try a numpy dtype
     # raise a consistent TypeError if failed
     try:
diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 7fa6011ee438d..6189aa0a08d2c 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -2277,12 +2277,18 @@ def name(self) -> str:  # type: ignore[override]
     @cache_readonly
     def numpy_dtype(self) -> np.dtype:
         """Return an instance of the related numpy dtype"""
-        if pa.types.is_date32(self.pyarrow_dtype) or pa.types.is_date64(
-            self.pyarrow_dtype
-        ):
-            # date32 and date64 are pyarrow timestamps but do not have a
-            # corresponding numpy dtype.
-            return np.dtype(object)
+        if pa.types.is_date32(self.pyarrow_dtype):
+            # pa.timestamp(unit).to_pandas_dtype() returns ns units
+            # regardless of the pyarrow timestamp units.
+            # This can be removed if/when pyarrow addresses it:
+            # https://github.com/apache/arrow/issues/34462
+            return np.dtype("datetime64[D]")
+        if pa.types.is_date64(self.pyarrow_dtype):
+            # pa.timestamp(unit).to_pandas_dtype() returns ns units
+            # regardless of the pyarrow timestamp units.
+            # This can be removed if/when pyarrow addresses it:
+            # https://github.com/apache/arrow/issues/34462
+            return np.dtype("datetime64[ms]")
         if pa.types.is_timestamp(self.pyarrow_dtype):
             # pa.timestamp(unit).to_pandas_dtype() returns ns units
             # regardless of the pyarrow timestamp units.
@@ -2459,18 +2465,6 @@ def _get_common_dtype(self, dtypes: list[DtypeObj]) -> DtypeObj | None:
 
         null_dtype = type(self)(pa.null())
 
-        # Cover cases where numpy does not have a corresponding dtype, but
-        # only one non-null dtype is received, or all dtypes are null.
-        single_dtype = {
-            dtype
-            for dtype in dtypes
-            if dtype != null_dtype
-        }
-        if len(single_dtype) == 0:
-            return null_dtype
-        if len(single_dtype) == 1:
-            return single_dtype.pop()
-
         new_dtype = find_common_type(
             [
                 dtype.numpy_dtype if isinstance(dtype, ArrowDtype) else dtype

From 9241196298ed76e89201c4a42ff83e466f52feaa Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 13:15:44 -0500
Subject: [PATCH 04/16] working on tests

---
 .../dtypes/cast/test_find_common_type.py      | 24 +++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index dbce6c6e899b1..36af26eaeb7ec 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -182,10 +182,30 @@ def test_interval_dtype_with_categorical(dtype):
             ["date32[pyarrow]", "null[pyarrow]"],
             "date32[day][pyarrow]",
         ),
+        (
+            ["date32[pyarrow]", "date32[pyarrow]"],
+            "date32[day][pyarrow]",
+        ),
+        (
+            ["date64[pyarrow]", "null[pyarrow]"],
+            "date64[ms][pyarrow]", # timestamp[ms][pyarrow]
+        ),
+        (
+            ["date64[pyarrow]", "date64[pyarrow]"],
+            "date64[ms][pyarrow]",
+        ),
+        (
+            ["date32[pyarrow]", "date64[pyarrow]"],
+            "date64[ms][pyarrow]", # timestamp[ms][pyarrow]
+        ),
+        (
+            ["date32[pyarrow]", "date64[pyarrow]", "datetime64[ms]"],
+            "timestamp[ms][pyarrow]",
+        ),
     ],
 )
-def test_pyarrow_dtypes(dtypes, expected):
-    """Test finding common types with pyarrow dtypes not in numpy."""
+def test_pyarrow_date_dtypes(dtypes, expected):
     source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
     result = find_common_type(source_dtypes)
+    print(f'{source_dtypes}: {result}')
     assert result == pandas_dtype(expected)
\ No newline at end of file

From 0f319928f5b1800325e881efbb9d43786654b082 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 14:16:21 -0500
Subject: [PATCH 05/16] xfail date64 tests

---
 .../dtypes/cast/test_find_common_type.py      | 48 +++++++++++++++----
 1 file changed, 40 insertions(+), 8 deletions(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index 36af26eaeb7ec..c8cc653e2f097 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -186,18 +186,10 @@ def test_interval_dtype_with_categorical(dtype):
             ["date32[pyarrow]", "date32[pyarrow]"],
             "date32[day][pyarrow]",
         ),
-        (
-            ["date64[pyarrow]", "null[pyarrow]"],
-            "date64[ms][pyarrow]", # timestamp[ms][pyarrow]
-        ),
         (
             ["date64[pyarrow]", "date64[pyarrow]"],
             "date64[ms][pyarrow]",
         ),
-        (
-            ["date32[pyarrow]", "date64[pyarrow]"],
-            "date64[ms][pyarrow]", # timestamp[ms][pyarrow]
-        ),
         (
             ["date32[pyarrow]", "date64[pyarrow]", "datetime64[ms]"],
             "timestamp[ms][pyarrow]",
@@ -205,6 +197,46 @@ def test_interval_dtype_with_categorical(dtype):
     ],
 )
 def test_pyarrow_date_dtypes(dtypes, expected):
+    source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
+    result = find_common_type(source_dtypes)
+    assert result == pandas_dtype(expected)
+
+@pytest.mark.xfail(reason="""
+                   Finding common pyarrow dtypes relies on conversion
+                   to numpy dtypes and then back to pyarrow dtypes.
+                   
+                   We have:
+                   >>> pa.from_numpy_dtype(np.dtype('datetime64[D]'))
+                   DataType(date32[day])
+                   >>> pa.from_numpy_dtype(np.dtype('datetime64[ms]'))
+                   TimestampType(timestamp[ms])
+
+                   To fix this test, we would need to have
+                   >>> pa.from_numpy_dtype(np.dtype('datetime64[ms]'))
+                   DataType(date64[ms])
+
+                   But date64 isn't the same as datetime64[ms]. date64
+                   is meant to represent a date (without time) only,
+                   represented in milliseconds (see
+                   https://github.com/apache/arrow/issues/15032#issuecomment-1368096718).
+
+                   Hence, some date64-related common type computations
+                   end up becoming cast to timestamps rather than date64.
+                   """)
+@pytest.mark.parametrize(
+    "dtypes,expected",
+    [
+        (
+            ["date64[pyarrow]", "null[pyarrow]"],
+            "date64[ms][pyarrow]",
+        ),
+        (
+            ["date32[pyarrow]", "date64[pyarrow]"],
+            "date64[ms][pyarrow]",
+        ),
+    ],
+)
+def test_pyarrow_date64_dtype(dtypes, expected):
     source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
     result = find_common_type(source_dtypes)
     print(f'{source_dtypes}: {result}')

From 3fea3e0a3f66a1487521ba61355d25daa4bcd7da Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 14:17:40 -0500
Subject: [PATCH 06/16] working on tests

---
 pandas/tests/dtypes/cast/test_find_common_type.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index c8cc653e2f097..d7f97090a8fbf 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -211,9 +211,8 @@ def test_pyarrow_date_dtypes(dtypes, expected):
                    >>> pa.from_numpy_dtype(np.dtype('datetime64[ms]'))
                    TimestampType(timestamp[ms])
 
-                   To fix this test, we would need to have
-                   >>> pa.from_numpy_dtype(np.dtype('datetime64[ms]'))
-                   DataType(date64[ms])
+                   To fix this test, we would need to have an exception
+                   that makes datetime64[ms] convert to date64[ms].
 
                    But date64 isn't the same as datetime64[ms]. date64
                    is meant to represent a date (without time) only,

From ac77415aafb9acea12b5274aea40c8fcf7917226 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 14:21:30 -0500
Subject: [PATCH 07/16] remove print statement from test

---
 pandas/tests/dtypes/cast/test_find_common_type.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index d7f97090a8fbf..14f120805ec0e 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -238,5 +238,4 @@ def test_pyarrow_date_dtypes(dtypes, expected):
 def test_pyarrow_date64_dtype(dtypes, expected):
     source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
     result = find_common_type(source_dtypes)
-    print(f'{source_dtypes}: {result}')
     assert result == pandas_dtype(expected)
\ No newline at end of file

From 608a43df797d6d3c986085bd90e43242b6233fe3 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 14:27:27 -0500
Subject: [PATCH 08/16] lint

---
 doc/source/whatsnew/v3.0.0.rst                    | 2 +-
 pandas/tests/dtypes/cast/test_find_common_type.py | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 992dcc42521b4..4560e5912976a 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -1108,13 +1108,13 @@ Numeric
 
 Conversion
 ^^^^^^^^^^
+- Bug in :meth:`ArrowDtype._get_common_dtype` and :meth:`ExtentionDtype._get_common_dtype` when using ``date32[pyarrow]`` and ``date64[pyarrow]`` types (:issue:`62343`)
 - Bug in :meth:`DataFrame.astype` not casting ``values`` for Arrow-based dictionary dtype correctly (:issue:`58479`)
 - Bug in :meth:`DataFrame.update` bool dtype being converted to object (:issue:`55509`)
 - Bug in :meth:`Series.astype` might modify read-only array inplace when casting to a string dtype (:issue:`57212`)
 - Bug in :meth:`Series.convert_dtypes` and :meth:`DataFrame.convert_dtypes` removing timezone information for objects with :class:`ArrowDtype` (:issue:`60237`)
 - Bug in :meth:`Series.reindex` not maintaining ``float32`` type when a ``reindex`` introduces a missing value (:issue:`45857`)
 - Bug in :meth:`to_datetime` and :meth:`to_timedelta` with input ``None`` returning ``None`` instead of ``NaT``, inconsistent with other conversion methods (:issue:`23055`)
-- Bug in :meth:`ArrowDtype._get_common_dtype` and :meth:`ExtentionDtype._get_common_dtype` when using ``date32[pyarrow]`` and ``date64[pyarrow]`` types (:issue:`62343`)
 
 Strings
 ^^^^^^^
diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index 14f120805ec0e..68d337d589901 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -204,7 +204,7 @@ def test_pyarrow_date_dtypes(dtypes, expected):
 @pytest.mark.xfail(reason="""
                    Finding common pyarrow dtypes relies on conversion
                    to numpy dtypes and then back to pyarrow dtypes.
-                   
+
                    We have:
                    >>> pa.from_numpy_dtype(np.dtype('datetime64[D]'))
                    DataType(date32[day])
@@ -238,4 +238,4 @@ def test_pyarrow_date_dtypes(dtypes, expected):
 def test_pyarrow_date64_dtype(dtypes, expected):
     source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
     result = find_common_type(source_dtypes)
-    assert result == pandas_dtype(expected)
\ No newline at end of file
+    assert result == pandas_dtype(expected)

From d3680a125ed65dd8ab3ebde7ff40b10afd846fd4 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 8 Nov 2025 19:32:38 +0000
Subject: [PATCH 09/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 pandas/tests/dtypes/cast/test_find_common_type.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index 68d337d589901..b287aa4dcd828 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -201,7 +201,9 @@ def test_pyarrow_date_dtypes(dtypes, expected):
     result = find_common_type(source_dtypes)
     assert result == pandas_dtype(expected)
 
-@pytest.mark.xfail(reason="""
+
+@pytest.mark.xfail(
+    reason="""
                    Finding common pyarrow dtypes relies on conversion
                    to numpy dtypes and then back to pyarrow dtypes.
 
@@ -221,7 +223,8 @@ def test_pyarrow_date_dtypes(dtypes, expected):
 
                    Hence, some date64-related common type computations
                    end up becoming cast to timestamps rather than date64.
-                   """)
+                   """
+)
 @pytest.mark.parametrize(
     "dtypes,expected",
     [

From 7ff8825f9ee7fa65f52c418653346d71a2a90712 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 15:13:55 -0500
Subject: [PATCH 10/16] skip pyarrow tests if no pyarrow

---
 pandas/tests/dtypes/cast/test_find_common_type.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index b287aa4dcd828..942a331ccd138 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -10,6 +10,8 @@
     PeriodDtype,
 )
 
+import pandas.util._test_decorators as td
+
 from pandas import (
     Categorical,
     Index,
@@ -165,6 +167,7 @@ def test_interval_dtype(left, right):
         assert result == object
 
 
+@td.skip_if_no("pyarrow")
 @pytest.mark.parametrize("dtype", interval_dtypes)
 def test_interval_dtype_with_categorical(dtype):
     obj = Index([], dtype=dtype)
@@ -175,6 +178,7 @@ def test_interval_dtype_with_categorical(dtype):
     assert result == dtype
 
 
+@td.skip_if_no("pyarrow")
 @pytest.mark.parametrize(
     "dtypes,expected",
     [
@@ -202,6 +206,7 @@ def test_pyarrow_date_dtypes(dtypes, expected):
     assert result == pandas_dtype(expected)
 
 
+@td.skip_if_no("pyarrow")
 @pytest.mark.xfail(
     reason="""
                    Finding common pyarrow dtypes relies on conversion

From 220e2906fb63e4ab7aa823b5a6b43d2dbccd6ba9 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sat, 8 Nov 2025 15:14:52 -0500
Subject: [PATCH 11/16] ruff format

---
 pandas/tests/dtypes/cast/test_find_common_type.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index 942a331ccd138..c1caca6ff34fb 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -1,6 +1,8 @@
 import numpy as np
 import pytest
 
+import pandas.util._test_decorators as td
+
 from pandas.core.dtypes.cast import find_common_type
 from pandas.core.dtypes.common import pandas_dtype
 from pandas.core.dtypes.dtypes import (
@@ -10,8 +12,6 @@
     PeriodDtype,
 )
 
-import pandas.util._test_decorators as td
-
 from pandas import (
     Categorical,
     Index,

From a187f86f452f9be092b526b0400685d8ae253101 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sun, 9 Nov 2025 10:08:48 -0500
Subject: [PATCH 12/16] removing xfail

---
 pandas/tests/extension/test_arrow.py | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/pandas/tests/extension/test_arrow.py b/pandas/tests/extension/test_arrow.py
index 875aa38481ecf..3f772e4d16431 100644
--- a/pandas/tests/extension/test_arrow.py
+++ b/pandas/tests/extension/test_arrow.py
@@ -1085,13 +1085,7 @@ def test_comp_masked_numpy(self, masked_dtype, comparison_op):
         expected = pd.Series(exp, dtype=ArrowDtype(pa.bool_()))
         tm.assert_series_equal(result, expected)
 
-    def test_loc_setitem_with_expansion_preserves_ea_index_dtype(self, data, request):
-        pa_dtype = data.dtype.pyarrow_dtype
-        if pa.types.is_date(pa_dtype):
-            mark = pytest.mark.xfail(
-                reason="GH#62343 incorrectly casts to timestamp[ms][pyarrow]"
-            )
-            request.applymarker(mark)
+    def test_loc_setitem_with_expansion_preserves_ea_index_dtype(self, data):
         super().test_loc_setitem_with_expansion_preserves_ea_index_dtype(data)
 
 

From 74552ce3ef232b60ac309bbabb1e63cdd8ce940e Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sun, 9 Nov 2025 10:39:47 -0500
Subject: [PATCH 13/16] xfail date64

---
 pandas/tests/extension/test_arrow.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pandas/tests/extension/test_arrow.py b/pandas/tests/extension/test_arrow.py
index 3f772e4d16431..4a6ec68d9417d 100644
--- a/pandas/tests/extension/test_arrow.py
+++ b/pandas/tests/extension/test_arrow.py
@@ -1085,7 +1085,13 @@ def test_comp_masked_numpy(self, masked_dtype, comparison_op):
         expected = pd.Series(exp, dtype=ArrowDtype(pa.bool_()))
         tm.assert_series_equal(result, expected)
 
-    def test_loc_setitem_with_expansion_preserves_ea_index_dtype(self, data):
+    def test_loc_setitem_with_expansion_preserves_ea_index_dtype(self, data, request):
+        pa_dtype = data.dtype.pyarrow_dtype
+        if pa.types.is_date64(pa_dtype):
+            mark = pytest.mark.xfail(
+                reason="GH#62343 incorrectly casts date64 to timestamp[ms][pyarrow]"
+            )
+            request.applymarker(mark)
         super().test_loc_setitem_with_expansion_preserves_ea_index_dtype(data)
 
 

From 495f85eea68642be93d5571a2f418cdee8eeb264 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sun, 9 Nov 2025 10:50:26 -0500
Subject: [PATCH 14/16] remove date type as xfail in test_get_common_dtype

---
 pandas/tests/extension/test_arrow.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pandas/tests/extension/test_arrow.py b/pandas/tests/extension/test_arrow.py
index 4a6ec68d9417d..44bcbe494d507 100644
--- a/pandas/tests/extension/test_arrow.py
+++ b/pandas/tests/extension/test_arrow.py
@@ -650,8 +650,7 @@ def test_construct_from_string_another_type_raises(self, dtype):
     def test_get_common_dtype(self, dtype, request):
         pa_dtype = dtype.pyarrow_dtype
         if (
-            pa.types.is_date(pa_dtype)
-            or pa.types.is_time(pa_dtype)
+            pa.types.is_time(pa_dtype)
             or (pa.types.is_timestamp(pa_dtype) and pa_dtype.tz is not None)
             or pa.types.is_binary(pa_dtype)
             or pa.types.is_decimal(pa_dtype)

From a4f89dd75db32d0a55cd29d325ce125fc6388037 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sun, 9 Nov 2025 11:23:12 -0500
Subject: [PATCH 15/16] xfail is_date64 for test_get_common_dtype

---
 pandas/tests/extension/test_arrow.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pandas/tests/extension/test_arrow.py b/pandas/tests/extension/test_arrow.py
index 44bcbe494d507..f458c52709ce1 100644
--- a/pandas/tests/extension/test_arrow.py
+++ b/pandas/tests/extension/test_arrow.py
@@ -650,7 +650,8 @@ def test_construct_from_string_another_type_raises(self, dtype):
     def test_get_common_dtype(self, dtype, request):
         pa_dtype = dtype.pyarrow_dtype
         if (
-            pa.types.is_time(pa_dtype)
+            pa.types.is_date64(pa_dtype)
+            or pa.types.is_time(pa_dtype)
             or (pa.types.is_timestamp(pa_dtype) and pa_dtype.tz is not None)
             or pa.types.is_binary(pa_dtype)
             or pa.types.is_decimal(pa_dtype)

From ea3f900c62222e41858ec6105e80347f2ae7c785 Mon Sep 17 00:00:00 2001
From: nli307 <nli307@gatech.edu>
Date: Sun, 9 Nov 2025 11:33:08 -0500
Subject: [PATCH 16/16] remove pyarrow tests from test_find_common_type,
 already covered by tests in test_arrow

---
 .../dtypes/cast/test_find_common_type.py      | 74 -------------------
 1 file changed, 74 deletions(-)

diff --git a/pandas/tests/dtypes/cast/test_find_common_type.py b/pandas/tests/dtypes/cast/test_find_common_type.py
index c1caca6ff34fb..83ef7382fbe8a 100644
--- a/pandas/tests/dtypes/cast/test_find_common_type.py
+++ b/pandas/tests/dtypes/cast/test_find_common_type.py
@@ -1,8 +1,6 @@
 import numpy as np
 import pytest
 
-import pandas.util._test_decorators as td
-
 from pandas.core.dtypes.cast import find_common_type
 from pandas.core.dtypes.common import pandas_dtype
 from pandas.core.dtypes.dtypes import (
@@ -167,7 +165,6 @@ def test_interval_dtype(left, right):
         assert result == object
 
 
-@td.skip_if_no("pyarrow")
 @pytest.mark.parametrize("dtype", interval_dtypes)
 def test_interval_dtype_with_categorical(dtype):
     obj = Index([], dtype=dtype)
@@ -176,74 +173,3 @@ def test_interval_dtype_with_categorical(dtype):
 
     result = find_common_type([dtype, cat.dtype])
     assert result == dtype
-
-
-@td.skip_if_no("pyarrow")
-@pytest.mark.parametrize(
-    "dtypes,expected",
-    [
-        (
-            ["date32[pyarrow]", "null[pyarrow]"],
-            "date32[day][pyarrow]",
-        ),
-        (
-            ["date32[pyarrow]", "date32[pyarrow]"],
-            "date32[day][pyarrow]",
-        ),
-        (
-            ["date64[pyarrow]", "date64[pyarrow]"],
-            "date64[ms][pyarrow]",
-        ),
-        (
-            ["date32[pyarrow]", "date64[pyarrow]", "datetime64[ms]"],
-            "timestamp[ms][pyarrow]",
-        ),
-    ],
-)
-def test_pyarrow_date_dtypes(dtypes, expected):
-    source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
-    result = find_common_type(source_dtypes)
-    assert result == pandas_dtype(expected)
-
-
-@td.skip_if_no("pyarrow")
-@pytest.mark.xfail(
-    reason="""
-                   Finding common pyarrow dtypes relies on conversion
-                   to numpy dtypes and then back to pyarrow dtypes.
-
-                   We have:
-                   >>> pa.from_numpy_dtype(np.dtype('datetime64[D]'))
-                   DataType(date32[day])
-                   >>> pa.from_numpy_dtype(np.dtype('datetime64[ms]'))
-                   TimestampType(timestamp[ms])
-
-                   To fix this test, we would need to have an exception
-                   that makes datetime64[ms] convert to date64[ms].
-
-                   But date64 isn't the same as datetime64[ms]. date64
-                   is meant to represent a date (without time) only,
-                   represented in milliseconds (see
-                   https://github.com/apache/arrow/issues/15032#issuecomment-1368096718).
-
-                   Hence, some date64-related common type computations
-                   end up becoming cast to timestamps rather than date64.
-                   """
-)
-@pytest.mark.parametrize(
-    "dtypes,expected",
-    [
-        (
-            ["date64[pyarrow]", "null[pyarrow]"],
-            "date64[ms][pyarrow]",
-        ),
-        (
-            ["date32[pyarrow]", "date64[pyarrow]"],
-            "date64[ms][pyarrow]",
-        ),
-    ],
-)
-def test_pyarrow_date64_dtype(dtypes, expected):
-    source_dtypes = [pandas_dtype(dtype) for dtype in dtypes]
-    result = find_common_type(source_dtypes)
-    assert result == pandas_dtype(expected)