From dffcccb5a9878f6337ab581297a936317c6a1ec5 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 9 May 2023 16:01:44 -0700
Subject: [PATCH 1/2] BUG: SparseDtype requires numpy dtype

---
 doc/source/whatsnew/v2.1.0.rst            |  1 +
 pandas/core/arrays/sparse/dtype.py        |  2 ++
 pandas/tests/arrays/sparse/test_astype.py | 16 +---------------
 pandas/tests/arrays/sparse/test_dtype.py  |  6 ++++++
 4 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/doc/source/whatsnew/v2.1.0.rst b/doc/source/whatsnew/v2.1.0.rst
index 62d56f684a11d..b98d3f9414ccc 100644
--- a/doc/source/whatsnew/v2.1.0.rst
+++ b/doc/source/whatsnew/v2.1.0.rst
@@ -424,6 +424,7 @@ Reshaping
 Sparse
 ^^^^^^
 - Bug in :meth:`arrays.SparseArray.map` allowed the fill value to be included in the sparse values (:issue:`52095`)
+- Bug in :class:`SparseDtype` constructor failing to raise ``TypeError`` when given an incompatible ``dtype`` for its subtype, which must be a ``numpy`` dtype (:issue:`??`)
 -
 
 ExtensionArray
diff --git a/pandas/core/arrays/sparse/dtype.py b/pandas/core/arrays/sparse/dtype.py
index dadd161ceeb38..e29e21bc38108 100644
--- a/pandas/core/arrays/sparse/dtype.py
+++ b/pandas/core/arrays/sparse/dtype.py
@@ -91,6 +91,8 @@ def __init__(self, dtype: Dtype = np.float64, fill_value: Any = None) -> None:
         dtype = pandas_dtype(dtype)
         if is_string_dtype(dtype):
             dtype = np.dtype("object")
+        if not isinstance(dtype, np.dtype):
+            raise TypeError("SparseDtype subtype must be a numpy dtype")
 
         if fill_value is None:
             fill_value = na_value_for_dtype(dtype)
diff --git a/pandas/tests/arrays/sparse/test_astype.py b/pandas/tests/arrays/sparse/test_astype.py
index 86d69610059b3..d729a31668ade 100644
--- a/pandas/tests/arrays/sparse/test_astype.py
+++ b/pandas/tests/arrays/sparse/test_astype.py
@@ -3,11 +3,7 @@
 
 from pandas._libs.sparse import IntIndex
 
-from pandas import (
-    DataFrame,
-    Series,
-    Timestamp,
-)
+from pandas import Timestamp
 import pandas._testing as tm
 from pandas.core.arrays.sparse import (
     SparseArray,
@@ -135,13 +131,3 @@ def test_astype_dt64_to_int64(self):
         arr3 = SparseArray(values, dtype=dtype)
         result3 = arr3.astype("int64")
         tm.assert_numpy_array_equal(result3, expected)
-
-
-def test_dtype_sparse_with_fill_value_not_present_in_data():
-    # GH 49987
-    df = DataFrame([["a", 0], ["b", 1], ["b", 2]], columns=["A", "B"])
-    result = df["A"].astype(SparseDtype("category", fill_value="c"))
-    expected = Series(
-        ["a", "b", "b"], name="A", dtype=SparseDtype("object", fill_value="c")
-    )
-    tm.assert_series_equal(result, expected)
diff --git a/pandas/tests/arrays/sparse/test_dtype.py b/pandas/tests/arrays/sparse/test_dtype.py
index 58fedbd3e4231..f001372eb6a5f 100644
--- a/pandas/tests/arrays/sparse/test_dtype.py
+++ b/pandas/tests/arrays/sparse/test_dtype.py
@@ -207,3 +207,9 @@ def test_repr():
     result = str(SparseDtype(object, fill_value="0"))
     expected = "Sparse[object, '0']"
     assert result == expected
+
+
+def test_sparse_dtype_subtype_must_be_numpy_dtype():
+    msg = "SparseDtype subtype must be a numpy dtype"
+    with pytest.raises(TypeError, match=msg):
+        SparseDtype("category", fill_value="c")

From 893e9d44f2e2b206d9e8325b33f66ad86eebaf17 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 9 May 2023 16:02:47 -0700
Subject: [PATCH 2/2] GH ref

---
 doc/source/whatsnew/v2.1.0.rst           | 2 +-
 pandas/core/arrays/sparse/dtype.py       | 1 +
 pandas/tests/arrays/sparse/test_dtype.py | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v2.1.0.rst b/doc/source/whatsnew/v2.1.0.rst
index b98d3f9414ccc..64c8f06349449 100644
--- a/doc/source/whatsnew/v2.1.0.rst
+++ b/doc/source/whatsnew/v2.1.0.rst
@@ -423,8 +423,8 @@ Reshaping
 
 Sparse
 ^^^^^^
+- Bug in :class:`SparseDtype` constructor failing to raise ``TypeError`` when given an incompatible ``dtype`` for its subtype, which must be a ``numpy`` dtype (:issue:`53160`)
 - Bug in :meth:`arrays.SparseArray.map` allowed the fill value to be included in the sparse values (:issue:`52095`)
-- Bug in :class:`SparseDtype` constructor failing to raise ``TypeError`` when given an incompatible ``dtype`` for its subtype, which must be a ``numpy`` dtype (:issue:`??`)
 -
 
 ExtensionArray
diff --git a/pandas/core/arrays/sparse/dtype.py b/pandas/core/arrays/sparse/dtype.py
index e29e21bc38108..5747ff807600d 100644
--- a/pandas/core/arrays/sparse/dtype.py
+++ b/pandas/core/arrays/sparse/dtype.py
@@ -92,6 +92,7 @@ def __init__(self, dtype: Dtype = np.float64, fill_value: Any = None) -> None:
         if is_string_dtype(dtype):
             dtype = np.dtype("object")
         if not isinstance(dtype, np.dtype):
+            # GH#53160
             raise TypeError("SparseDtype subtype must be a numpy dtype")
 
         if fill_value is None:
diff --git a/pandas/tests/arrays/sparse/test_dtype.py b/pandas/tests/arrays/sparse/test_dtype.py
index f001372eb6a5f..88f8577ded5b0 100644
--- a/pandas/tests/arrays/sparse/test_dtype.py
+++ b/pandas/tests/arrays/sparse/test_dtype.py
@@ -210,6 +210,7 @@ def test_repr():
 
 
 def test_sparse_dtype_subtype_must_be_numpy_dtype():
+    # GH#53160
     msg = "SparseDtype subtype must be a numpy dtype"
     with pytest.raises(TypeError, match=msg):
         SparseDtype("category", fill_value="c")