From 339b2e053cca2f528efabd749998746c26376d16 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Mon, 25 Mar 2024 02:08:27 +0300
Subject: [PATCH 01/12] deprecate epoch date format in to_json

---
 doc/source/whatsnew/v2.2.2.rst                |  2 +-
 pandas/core/generic.py                        | 12 ++++++++++++
 .../tests/io/json/test_json_table_schema.py   | 11 ++++++++---
 pandas/tests/io/json/test_pandas.py           | 19 +++++++++++++++++--
 4 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/doc/source/whatsnew/v2.2.2.rst b/doc/source/whatsnew/v2.2.2.rst
index 54084abab7817..5484b25f00377 100644
--- a/doc/source/whatsnew/v2.2.2.rst
+++ b/doc/source/whatsnew/v2.2.2.rst
@@ -30,7 +30,7 @@ Bug fixes
 
 Other
 ~~~~~
--
+- Deprecated using ``epoch`` date format in :meth:`DataFrame.to_json` and :meth:`Series.to_json`, use ``iso`` instead.
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_222.contributors:
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index c0eda7f022d8f..e8587352d7243 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2365,6 +2365,10 @@ def to_json(
             Accepted args are 'w' (writing) and 'a' (append) only.
             mode='a' is only supported when lines is True and orient is 'records'.
 
+        .. deprecated:: 2.2.2
+            'epoch' date format is deprecated and will be removed in a future version,
+            please use 'iso' instead.
+
         Returns
         -------
         None or str
@@ -2530,6 +2534,14 @@ def to_json(
             date_format = "iso"
         elif date_format is None:
             date_format = "epoch"
+        elif date_format == "epoch":
+            # GH#57063
+            warnings.warn(
+                "'Epoch' date format is deprecated and will be removed in a future "
+                "version, please use 'iso' date format instead.",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
 
         config.is_nonnegative_int(indent)
         indent = indent or 0
diff --git a/pandas/tests/io/json/test_json_table_schema.py b/pandas/tests/io/json/test_json_table_schema.py
index afc9974c75e6a..e9ff96d7f182a 100644
--- a/pandas/tests/io/json/test_json_table_schema.py
+++ b/pandas/tests/io/json/test_json_table_schema.py
@@ -451,12 +451,17 @@ def test_to_json_categorical_index(self):
         assert result == expected
 
     def test_date_format_raises(self, df_table):
-        msg = (
+        error_msg = (
             "Trying to write with `orient='table'` and `date_format='epoch'`. Table "
             "Schema requires dates to be formatted with `date_format='iso'`"
         )
-        with pytest.raises(ValueError, match=msg):
-            df_table.to_json(orient="table", date_format="epoch")
+        warning_msg = (
+            "'Epoch' date format is deprecated and will be removed in a future "
+            "version, please use 'iso' date format instead."
+        )
+        with pytest.raises(ValueError, match=error_msg):
+            with tm.assert_produces_warning(FutureWarning, match=warning_msg):
+                df_table.to_json(orient="table", date_format="epoch")
 
         # others work
         df_table.to_json(orient="table", date_format="iso")
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index db120588b234c..bc29797cde817 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -940,7 +940,12 @@ def test_date_unit(self, unit, datetime_frame):
         df.iloc[2, dl] = Timestamp("21460101 20:43:42")
         df.iloc[4, dl] = pd.NaT
 
-        json = df.to_json(date_format="epoch", date_unit=unit)
+        msg = (
+            "'Epoch' date format is deprecated and will be removed in a future "
+            "version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            json = df.to_json(date_format="epoch", date_unit=unit)
 
         # force date unit
         result = read_json(StringIO(json), date_unit=unit)
@@ -1669,7 +1674,17 @@ def test_read_json_with_very_long_file_path(self, compression):
     def test_timedelta_as_label(self, date_format, key):
         df = DataFrame([[1]], columns=[pd.Timedelta("1D")])
         expected = f'{{"{key}":{{"0":1}}}}'
-        result = df.to_json(date_format=date_format)
+
+        expected_warning = None
+        if date_format == "epoch":
+            expected_warning = FutureWarning
+
+        msg = (
+            "'Epoch' date format is deprecated and will be removed in a future "
+            "version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(expected_warning, match=msg):
+            result = df.to_json(date_format=date_format)
 
         assert result == expected
 

From 41156fdc7d895c9277a53bc2618e3009b8490425 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Mon, 25 Mar 2024 05:43:22 +0300
Subject: [PATCH 02/12] Fix tests

---
 pandas/core/generic.py              |  9 +++++----
 pandas/tests/io/json/test_pandas.py | 19 +++++++++++++++++--
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index e8587352d7243..a06e96498b134 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2328,6 +2328,11 @@ def to_json(
             'iso' = ISO8601. The default depends on the `orient`. For
             ``orient='table'``, the default is 'iso'. For all other orients,
             the default is 'epoch'.
+
+            .. deprecated:: 2.2.2
+                'epoch' date format is deprecated and will be removed in a future
+                version, please use 'iso' instead.
+
         double_precision : int, default 10
             The number of decimal places to use when encoding
             floating point values. The possible maximal value is 15.
@@ -2365,10 +2370,6 @@ def to_json(
             Accepted args are 'w' (writing) and 'a' (append) only.
             mode='a' is only supported when lines is True and orient is 'records'.
 
-        .. deprecated:: 2.2.2
-            'epoch' date format is deprecated and will be removed in a future version,
-            please use 'iso' instead.
-
         Returns
         -------
         None or str
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index bc29797cde817..070b569cef7a5 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -835,15 +835,23 @@ def test_date_index_and_values(self, date_format, as_object, date_typ):
             data.append("a")
 
         ser = Series(data, index=data)
-        result = ser.to_json(date_format=date_format)
 
+        expected_warning = None
         if date_format == "epoch":
             expected = '{"1577836800000":1577836800000,"null":null}'
+            expected_warning = FutureWarning
         else:
             expected = (
                 '{"2020-01-01T00:00:00.000":"2020-01-01T00:00:00.000","null":null}'
             )
 
+        msg = (
+            "'Epoch' date format is deprecated and will be removed in a future "
+            "version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(expected_warning, match=msg):
+            result = ser.to_json(date_format=date_format)
+
         if as_object:
             expected = expected.replace("}", ',"a":"a"}')
 
@@ -1111,17 +1119,24 @@ def test_timedelta_to_json(self, as_object, date_format, timedelta_typ):
             data.append("a")
 
         ser = Series(data, index=data)
+        expected_warning = None
         if date_format == "iso":
             expected = (
                 '{"P1DT0H0M0S":"P1DT0H0M0S","P2DT0H0M0S":"P2DT0H0M0S","null":null}'
             )
         else:
+            expected_warning = FutureWarning
             expected = '{"86400000":86400000,"172800000":172800000,"null":null}'
 
         if as_object:
             expected = expected.replace("}", ',"a":"a"}')
 
-        result = ser.to_json(date_format=date_format)
+        msg = (
+            "'Epoch' date format is deprecated and will be removed in a future "
+            "version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(expected_warning, match=msg):
+            result = ser.to_json(date_format=date_format)
         assert result == expected
 
     @pytest.mark.parametrize("as_object", [True, False])

From 8fee0ea892692ce002da37c80911fa11e4cf70be Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Mon, 25 Mar 2024 05:55:15 +0300
Subject: [PATCH 03/12] Remove examples using epoch

---
 doc/source/user_guide/io.rst | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/doc/source/user_guide/io.rst b/doc/source/user_guide/io.rst
index db2326d5b9754..183283e37435c 100644
--- a/doc/source/user_guide/io.rst
+++ b/doc/source/user_guide/io.rst
@@ -1949,13 +1949,6 @@ Writing in ISO date format, with microseconds:
    json = dfd.to_json(date_format="iso", date_unit="us")
    json
 
-Epoch timestamps, in seconds:
-
-.. ipython:: python
-
-   json = dfd.to_json(date_format="epoch", date_unit="s")
-   json
-
 Writing to a file, with a date index and a date column:
 
 .. ipython:: python

From 80cd7fefcdfe7f0d8e08d3f538adf6339e62a97d Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Mon, 25 Mar 2024 21:10:53 +0300
Subject: [PATCH 04/12] Deprecate in v3.0.0

---
 doc/source/whatsnew/v2.2.2.rst | 2 +-
 doc/source/whatsnew/v3.0.0.rst | 1 +
 pandas/core/generic.py         | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v2.2.2.rst b/doc/source/whatsnew/v2.2.2.rst
index 5484b25f00377..54084abab7817 100644
--- a/doc/source/whatsnew/v2.2.2.rst
+++ b/doc/source/whatsnew/v2.2.2.rst
@@ -30,7 +30,7 @@ Bug fixes
 
 Other
 ~~~~~
-- Deprecated using ``epoch`` date format in :meth:`DataFrame.to_json` and :meth:`Series.to_json`, use ``iso`` instead.
+-
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_222.contributors:
diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index f748f6e23e003..74b95479d347e 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -182,6 +182,7 @@ Other Deprecations
 - Deprecated :meth:`Timestamp.utcnow`, use ``Timestamp.now("UTC")`` instead (:issue:`56680`)
 - Deprecated allowing non-keyword arguments in :meth:`Series.to_markdown` except ``buf``. (:issue:`57280`)
 - Deprecated allowing non-keyword arguments in :meth:`Series.to_string` except ``buf``. (:issue:`57280`)
+- Deprecated using ``epoch`` date format in :meth:`DataFrame.to_json` and :meth:`Series.to_json`, use ``iso`` instead.
 -
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index a06e96498b134..2ef54bfc8cb99 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2329,7 +2329,7 @@ def to_json(
             ``orient='table'``, the default is 'iso'. For all other orients,
             the default is 'epoch'.
 
-            .. deprecated:: 2.2.2
+            .. deprecated:: 3.0.0
                 'epoch' date format is deprecated and will be removed in a future
                 version, please use 'iso' instead.
 

From 5300d7e4124e60437b60f59ddac6d20fac998818 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Sun, 7 Apr 2024 01:16:04 +0300
Subject: [PATCH 05/12] Warn for using default format

---
 pandas/core/generic.py              |  7 ++++++
 pandas/tests/io/json/test_pandas.py | 39 ++++++++++++++++-------------
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 2ef54bfc8cb99..06914a462ac9b 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2535,6 +2535,13 @@ def to_json(
             date_format = "iso"
         elif date_format is None:
             date_format = "epoch"
+            if "m8[ns]" in self.dtypes.values or "M8[ns]" in self.dtypes.values:
+                warnings.warn(
+                    "The default 'Epoch' date format is deprecated and will be removed "
+                    "in a future version, please use 'iso' date format instead.",
+                    FutureWarning,
+                    stacklevel=find_stack_level(),
+                )
         elif date_format == "epoch":
             # GH#57063
             warnings.warn(
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index 070b569cef7a5..7cd1019de2b1f 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -137,16 +137,19 @@ def test_frame_non_unique_columns(self, orient, data):
         df = DataFrame(data, index=[1, 2], columns=["x", "x"])
 
         result = read_json(
-            StringIO(df.to_json(orient=orient)), orient=orient, convert_dates=["x"]
+            StringIO(df.to_json(orient=orient, date_format="iso")),
+            orient=orient,
+            convert_dates=["x"],
         )
         if orient == "values":
             expected = DataFrame(data)
             if expected.iloc[:, 0].dtype == "datetime64[ns]":
-                # orient == "values" by default will write Timestamp objects out
-                # in milliseconds; these are internally stored in nanosecond,
-                # so divide to get where we need
-                # TODO: a to_epoch method would also solve; see GH 14772
-                expected.isetitem(0, expected.iloc[:, 0].astype(np.int64) // 1000000)
+                expected.isetitem(
+                    0,
+                    expected.iloc[:, 0].apply(
+                        lambda x: x.isoformat(timespec="milliseconds")
+                    ),
+                )
         elif orient == "split":
             expected = df
             expected.columns = ["x", "x.1"]
@@ -807,22 +810,24 @@ def test_convert_dates(self, datetime_series, datetime_frame):
         df = datetime_frame
         df["date"] = Timestamp("20130101").as_unit("ns")
 
-        json = StringIO(df.to_json())
+        json = StringIO(df.to_json(date_format="iso"))
         result = read_json(json)
         tm.assert_frame_equal(result, df)
 
         df["foo"] = 1.0
-        json = StringIO(df.to_json(date_unit="ns"))
+        json = StringIO(df.to_json(date_unit="ns", date_format="iso"))
 
         result = read_json(json, convert_dates=False)
         expected = df.copy()
-        expected["date"] = expected["date"].values.view("i8")
+        expected["date"] = expected["date"].apply(
+            lambda x: x.isoformat(timespec="nanoseconds")
+        )
         expected["foo"] = expected["foo"].astype("int64")
         tm.assert_frame_equal(result, expected)
 
         # series
         ts = Series(Timestamp("20130101").as_unit("ns"), index=datetime_series.index)
-        json = StringIO(ts.to_json())
+        json = StringIO(ts.to_json(date_format="iso"))
         result = read_json(json, typ="series")
         tm.assert_series_equal(result, ts)
 
@@ -1091,9 +1096,9 @@ def test_timedelta2(self):
                 "c": date_range(start="20130101", periods=2),
             }
         )
-        data = StringIO(frame.to_json(date_unit="ns"))
+        data = StringIO(frame.to_json(date_unit="ns", date_format="iso"))
         result = read_json(data)
-        result["a"] = pd.to_timedelta(result.a, unit="ns")
+        result["a"] = pd.to_timedelta(result.a)
         result["c"] = pd.to_datetime(result.c)
         tm.assert_frame_equal(frame, result)
 
@@ -1229,12 +1234,12 @@ def test_datetime_tz(self):
 
         df_naive = df.copy()
         df_naive["A"] = tz_naive
-        expected = df_naive.to_json()
-        assert expected == df.to_json()
+        expected = df_naive.to_json(date_format="iso")
+        assert expected == df.to_json(date_format="iso").replace("000Z", "000")
 
         stz = Series(tz_range)
         s_naive = Series(tz_naive)
-        assert stz.to_json() == s_naive.to_json()
+        assert stz.to_json(date_format="iso") == s_naive.to_json(date_format="iso")
 
     def test_sparse(self):
         # GH4377 df.to_json segfaults with non-ndarray blocks
@@ -1499,7 +1504,7 @@ def test_to_json_from_json_columns_dtypes(self, orient):
                 ),
             }
         )
-        dfjson = expected.to_json(orient=orient)
+        dfjson = expected.to_json(orient=orient, date_format="iso")
 
         result = read_json(
             StringIO(dfjson),
@@ -1931,7 +1936,7 @@ def test_json_pandas_nulls(self, nulls_fixture, request):
             mark = pytest.mark.xfail(reason="not implemented")
             request.applymarker(mark)
 
-        result = DataFrame([[nulls_fixture]]).to_json()
+        result = DataFrame([[nulls_fixture]]).to_json(date_format="iso")
         assert result == '{"0":{"0":null}}'
 
     def test_readjson_bool_series(self):

From f59aa8087249d0bf1e8aed90ded9b26f47a41436 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Sun, 7 Apr 2024 02:29:33 +0300
Subject: [PATCH 06/12] Fix detection logic

---
 pandas/core/generic.py              |  3 ++-
 pandas/tests/io/json/test_pandas.py | 21 +++++++++++++--------
 pandas/tests/io/test_gcs.py         |  2 +-
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 06914a462ac9b..5c60c951ea114 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2535,7 +2535,8 @@ def to_json(
             date_format = "iso"
         elif date_format is None:
             date_format = "epoch"
-            if "m8[ns]" in self.dtypes.values or "M8[ns]" in self.dtypes.values:
+            dtypes = getattr(self.dtypes, "values", [self.dtypes])
+            if "m8[ns]" in dtypes or "M8[ns]" in dtypes:
                 warnings.warn(
                     "The default 'Epoch' date format is deprecated and will be removed "
                     "in a future version, please use 'iso' date format instead.",
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index 7cd1019de2b1f..d116d6f4c06cd 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -759,12 +759,12 @@ def test_series_with_dtype(self):
         "dtype,expected",
         [
             (True, Series(["2000-01-01"], dtype="datetime64[ns]")),
-            (False, Series([946684800000])),
+            (False, Series(["2000-01-01T00:00:00.000"])),
         ],
     )
     def test_series_with_dtype_datetime(self, dtype, expected):
         s = Series(["2000-01-01"], dtype="datetime64[ns]")
-        data = StringIO(s.to_json())
+        data = StringIO(s.to_json(date_format="iso"))
         result = read_json(data, typ="series", dtype=dtype)
         tm.assert_series_equal(result, expected)
 
@@ -1069,23 +1069,28 @@ def test_url(self, field, dtype, httpserver):
         assert result[field].dtype == dtype
 
     def test_timedelta(self):
-        converter = lambda x: pd.to_timedelta(x, unit="ms")
+        converter = lambda x: pd.to_timedelta(x)
 
         ser = Series([timedelta(23), timedelta(seconds=5)])
         assert ser.dtype == "timedelta64[ns]"
 
-        result = read_json(StringIO(ser.to_json()), typ="series").apply(converter)
+        result = read_json(
+            StringIO(ser.to_json(date_format="iso")), typ="series"
+        ).apply(converter)
         tm.assert_series_equal(result, ser)
 
         ser = Series([timedelta(23), timedelta(seconds=5)], index=Index([0, 1]))
         assert ser.dtype == "timedelta64[ns]"
-        result = read_json(StringIO(ser.to_json()), typ="series").apply(converter)
+        result = read_json(
+            StringIO(ser.to_json(date_format="iso")), typ="series"
+        ).apply(converter)
         tm.assert_series_equal(result, ser)
 
         frame = DataFrame([timedelta(23), timedelta(seconds=5)])
         assert frame[0].dtype == "timedelta64[ns]"
         tm.assert_frame_equal(
-            frame, read_json(StringIO(frame.to_json())).apply(converter)
+            frame,
+            read_json(StringIO(frame.to_json(date_format="iso"))).apply(converter),
         )
 
     def test_timedelta2(self):
@@ -1152,8 +1157,8 @@ def test_timedelta_to_json_fractional_precision(self, as_object, timedelta_typ):
         if as_object:
             ser = ser.astype(object)
 
-        result = ser.to_json()
-        expected = '{"42":42}'
+        result = ser.to_json(date_format="iso")
+        expected = '{"P0DT0H0M0.042S":"P0DT0H0M0.042S"}'
         assert result == expected
 
     def test_default_handler(self):
diff --git a/pandas/tests/io/test_gcs.py b/pandas/tests/io/test_gcs.py
index a4cf257296b09..e07bf7d545bde 100644
--- a/pandas/tests/io/test_gcs.py
+++ b/pandas/tests/io/test_gcs.py
@@ -78,7 +78,7 @@ def test_to_read_gcs(gcs_buffer, format, monkeypatch, capsys):
         df1.to_excel(path)
         df2 = read_excel(path, parse_dates=["dt"], index_col=0)
     elif format == "json":
-        df1.to_json(path)
+        df1.to_json(path, date_format="iso")
         df2 = read_json(path, convert_dates=["dt"])
     elif format == "parquet":
         pytest.importorskip("pyarrow")

From 9938eb50a41ef8d5d920a750b5fee95e11ee0104 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Tue, 9 Apr 2024 21:30:25 +0300
Subject: [PATCH 07/12] Keep default and expect warning

---
 pandas/core/generic.py              |   8 +-
 pandas/tests/io/json/test_pandas.py | 109 +++++++++++++++++++---------
 pandas/tests/io/test_gcs.py         |   7 +-
 3 files changed, 85 insertions(+), 39 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 5c60c951ea114..3999d94873e74 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2535,8 +2535,12 @@ def to_json(
             date_format = "iso"
         elif date_format is None:
             date_format = "epoch"
-            dtypes = getattr(self.dtypes, "values", [self.dtypes])
-            if "m8[ns]" in dtypes or "M8[ns]" in dtypes:
+            dtypes = (
+                self.dtypes.values
+                if self.ndim == 2
+                else np.array([self.dtype], dtype=object)
+            )
+            if any(lib.is_np_dtype(dtype, "mM") for dtype in dtypes):
                 warnings.warn(
                     "The default 'Epoch' date format is deprecated and will be removed "
                     "in a future version, please use 'iso' date format instead.",
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index d116d6f4c06cd..c6971e1f302aa 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -123,6 +123,7 @@ def test_frame_non_unique_index_raises(self, orient):
         with pytest.raises(ValueError, match=msg):
             df.to_json(orient=orient)
 
+    @pytest.mark.filterwarnings("ignore::FutureWarning")
     @pytest.mark.parametrize("orient", ["split", "values"])
     @pytest.mark.parametrize(
         "data",
@@ -137,19 +138,14 @@ def test_frame_non_unique_columns(self, orient, data):
         df = DataFrame(data, index=[1, 2], columns=["x", "x"])
 
         result = read_json(
-            StringIO(df.to_json(orient=orient, date_format="iso")),
+            StringIO(df.to_json(orient=orient)),
             orient=orient,
             convert_dates=["x"],
         )
         if orient == "values":
             expected = DataFrame(data)
             if expected.iloc[:, 0].dtype == "datetime64[ns]":
-                expected.isetitem(
-                    0,
-                    expected.iloc[:, 0].apply(
-                        lambda x: x.isoformat(timespec="milliseconds")
-                    ),
-                )
+                expected.isetitem(0, expected.iloc[:, 0].astype(np.int64) // 1000000)
         elif orient == "split":
             expected = df
             expected.columns = ["x", "x.1"]
@@ -759,12 +755,17 @@ def test_series_with_dtype(self):
         "dtype,expected",
         [
             (True, Series(["2000-01-01"], dtype="datetime64[ns]")),
-            (False, Series(["2000-01-01T00:00:00.000"])),
+            (False, Series([946684800000])),
         ],
     )
     def test_series_with_dtype_datetime(self, dtype, expected):
         s = Series(["2000-01-01"], dtype="datetime64[ns]")
-        data = StringIO(s.to_json(date_format="iso"))
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            data = StringIO(s.to_json())
         result = read_json(data, typ="series", dtype=dtype)
         tm.assert_series_equal(result, expected)
 
@@ -810,24 +811,29 @@ def test_convert_dates(self, datetime_series, datetime_frame):
         df = datetime_frame
         df["date"] = Timestamp("20130101").as_unit("ns")
 
-        json = StringIO(df.to_json(date_format="iso"))
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            json = StringIO(df.to_json())
         result = read_json(json)
         tm.assert_frame_equal(result, df)
 
         df["foo"] = 1.0
-        json = StringIO(df.to_json(date_unit="ns", date_format="iso"))
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            json = StringIO(df.to_json(date_unit="ns"))
 
         result = read_json(json, convert_dates=False)
         expected = df.copy()
-        expected["date"] = expected["date"].apply(
-            lambda x: x.isoformat(timespec="nanoseconds")
-        )
+        expected["date"] = expected["date"].values.view("i8")
         expected["foo"] = expected["foo"].astype("int64")
         tm.assert_frame_equal(result, expected)
 
         # series
         ts = Series(Timestamp("20130101").as_unit("ns"), index=datetime_series.index)
-        json = StringIO(ts.to_json(date_format="iso"))
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            json = StringIO(ts.to_json())
         result = read_json(json, typ="series")
         tm.assert_series_equal(result, ts)
 
@@ -1037,7 +1043,12 @@ def test_doc_example(self):
         dfj2["bools"] = True
         dfj2.index = date_range("20130101", periods=5)
 
-        json = StringIO(dfj2.to_json())
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            json = StringIO(dfj2.to_json())
         result = read_json(json, dtype={"ints": np.int64, "bools": np.bool_})
         tm.assert_frame_equal(result, result)
 
@@ -1069,29 +1080,31 @@ def test_url(self, field, dtype, httpserver):
         assert result[field].dtype == dtype
 
     def test_timedelta(self):
-        converter = lambda x: pd.to_timedelta(x)
+        converter = lambda x: pd.to_timedelta(x, unit="ms")
 
         ser = Series([timedelta(23), timedelta(seconds=5)])
         assert ser.dtype == "timedelta64[ns]"
 
-        result = read_json(
-            StringIO(ser.to_json(date_format="iso")), typ="series"
-        ).apply(converter)
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = read_json(StringIO(ser.to_json()), typ="series").apply(converter)
         tm.assert_series_equal(result, ser)
 
         ser = Series([timedelta(23), timedelta(seconds=5)], index=Index([0, 1]))
         assert ser.dtype == "timedelta64[ns]"
-        result = read_json(
-            StringIO(ser.to_json(date_format="iso")), typ="series"
-        ).apply(converter)
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = read_json(StringIO(ser.to_json()), typ="series").apply(converter)
         tm.assert_series_equal(result, ser)
 
         frame = DataFrame([timedelta(23), timedelta(seconds=5)])
         assert frame[0].dtype == "timedelta64[ns]"
-        tm.assert_frame_equal(
-            frame,
-            read_json(StringIO(frame.to_json(date_format="iso"))).apply(converter),
-        )
+
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            json = frame.to_json()
+        tm.assert_frame_equal(frame, read_json(StringIO(json)).apply(converter))
 
     def test_timedelta2(self):
         frame = DataFrame(
@@ -1101,9 +1114,14 @@ def test_timedelta2(self):
                 "c": date_range(start="20130101", periods=2),
             }
         )
-        data = StringIO(frame.to_json(date_unit="ns", date_format="iso"))
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            data = StringIO(frame.to_json(date_unit="ns"))
         result = read_json(data)
-        result["a"] = pd.to_timedelta(result.a)
+        result["a"] = pd.to_timedelta(result.a, unit="ns")
         result["c"] = pd.to_datetime(result.c)
         tm.assert_frame_equal(frame, result)
 
@@ -1154,11 +1172,18 @@ def test_timedelta_to_json(self, as_object, date_format, timedelta_typ):
     def test_timedelta_to_json_fractional_precision(self, as_object, timedelta_typ):
         data = [timedelta_typ(milliseconds=42)]
         ser = Series(data, index=data)
+        warn = FutureWarning
         if as_object:
             ser = ser.astype(object)
+            warn = None
 
-        result = ser.to_json(date_format="iso")
-        expected = '{"P0DT0H0M0.042S":"P0DT0H0M0.042S"}'
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(warn, match=msg):
+            result = ser.to_json()
+        expected = '{"42":42}'
         assert result == expected
 
     def test_default_handler(self):
@@ -1239,12 +1264,18 @@ def test_datetime_tz(self):
 
         df_naive = df.copy()
         df_naive["A"] = tz_naive
-        expected = df_naive.to_json(date_format="iso")
-        assert expected == df.to_json(date_format="iso").replace("000Z", "000")
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            expected = df_naive.to_json()
+            assert expected == df.to_json()
 
         stz = Series(tz_range)
         s_naive = Series(tz_naive)
-        assert stz.to_json(date_format="iso") == s_naive.to_json(date_format="iso")
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            assert stz.to_json() == s_naive.to_json()
 
     def test_sparse(self):
         # GH4377 df.to_json segfaults with non-ndarray blocks
@@ -1509,7 +1540,12 @@ def test_to_json_from_json_columns_dtypes(self, orient):
                 ),
             }
         )
-        dfjson = expected.to_json(orient=orient, date_format="iso")
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            dfjson = expected.to_json(orient=orient)
 
         result = read_json(
             StringIO(dfjson),
@@ -1935,13 +1971,14 @@ def test_to_s3(self, s3_public_bucket, s3so):
             timeout -= 0.1
             assert timeout > 0, "Timed out waiting for file to appear on moto"
 
+    @pytest.mark.filterwarnings("ignore::FutureWarning")
     def test_json_pandas_nulls(self, nulls_fixture, request):
         # GH 31615
         if isinstance(nulls_fixture, Decimal):
             mark = pytest.mark.xfail(reason="not implemented")
             request.applymarker(mark)
 
-        result = DataFrame([[nulls_fixture]]).to_json(date_format="iso")
+        result = DataFrame([[nulls_fixture]]).to_json()
         assert result == '{"0":{"0":null}}'
 
     def test_readjson_bool_series(self):
diff --git a/pandas/tests/io/test_gcs.py b/pandas/tests/io/test_gcs.py
index e07bf7d545bde..c4617d4eaed5c 100644
--- a/pandas/tests/io/test_gcs.py
+++ b/pandas/tests/io/test_gcs.py
@@ -78,7 +78,12 @@ def test_to_read_gcs(gcs_buffer, format, monkeypatch, capsys):
         df1.to_excel(path)
         df2 = read_excel(path, parse_dates=["dt"], index_col=0)
     elif format == "json":
-        df1.to_json(path, date_format="iso")
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            df1.to_json(path)
         df2 = read_json(path, convert_dates=["dt"])
     elif format == "parquet":
         pytest.importorskip("pyarrow")

From 75df145cb6e16238b750284894bdc7295f17b3dd Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Tue, 9 Apr 2024 22:10:27 +0300
Subject: [PATCH 08/12] Add deprecation test

---
 pandas/tests/io/json/test_pandas.py | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index c6971e1f302aa..32aea7de03c7d 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -974,6 +974,33 @@ def test_date_unit(self, unit, datetime_frame):
         result = read_json(StringIO(json), date_unit=None)
         tm.assert_frame_equal(result, df)
 
+    @pytest.mark.parametrize(
+        "df, warn",
+        [
+            (DataFrame({"A": ["a", "b", "c"], "B": np.arange(3)}), None),
+            (DataFrame({"A": [True, False, False]}), None),
+            (
+                DataFrame(
+                    {"A": ["a", "b", "c"], "B": pd.to_timedelta(np.arange(3), unit="D")}
+                ),
+                FutureWarning,
+            ),
+            (
+                DataFrame(
+                    {"A": pd.to_datetime(["2020-01-01", "2020-02-01", "2020-03-01"])}
+                ),
+                FutureWarning,
+            ),
+        ],
+    )
+    def test_default_epoch_date_format_deprecated(self, df, warn):
+        msg = (
+            "The default 'Epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        with tm.assert_produces_warning(warn, match=msg):
+            df.to_json()
+
     @pytest.mark.parametrize("unit", ["s", "ms", "us"])
     def test_iso_non_nano_datetimes(self, unit):
         # Test that numpy datetimes

From f9c39b4bee60c5f75e2ab4b331c245fbe097919b Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Sat, 13 Apr 2024 21:41:21 +0300
Subject: [PATCH 09/12] Final changes

---
 doc/source/user_guide/io.rst        | 4 ++++
 pandas/tests/io/json/test_pandas.py | 9 ++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/doc/source/user_guide/io.rst b/doc/source/user_guide/io.rst
index 183283e37435c..cf8e71fc582c6 100644
--- a/doc/source/user_guide/io.rst
+++ b/doc/source/user_guide/io.rst
@@ -1952,6 +1952,7 @@ Writing in ISO date format, with microseconds:
 Writing to a file, with a date index and a date column:
 
 .. ipython:: python
+   :okwarning:
 
    dfj2 = dfj.copy()
    dfj2["date"] = pd.Timestamp("20130101")
@@ -2131,6 +2132,7 @@ Preserve string indices:
 Dates written in nanoseconds need to be read back in nanoseconds:
 
 .. ipython:: python
+   :okwarning:
 
    from io import StringIO
    json = dfj2.to_json(date_unit="ns")
@@ -2268,6 +2270,7 @@ other attributes. You can use the orient ``table`` to build
 a JSON string with two fields, ``schema`` and ``data``.
 
 .. ipython:: python
+   :okwarning:
 
    df = pd.DataFrame(
        {
@@ -2377,6 +2380,7 @@ the preservation of metadata such as dtypes and index names in a
 round-trippable manner.
 
 .. ipython:: python
+   :okwarning:
 
    df = pd.DataFrame(
        {
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index 32aea7de03c7d..0bce482de5a79 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -138,13 +138,15 @@ def test_frame_non_unique_columns(self, orient, data):
         df = DataFrame(data, index=[1, 2], columns=["x", "x"])
 
         result = read_json(
-            StringIO(df.to_json(orient=orient)),
-            orient=orient,
-            convert_dates=["x"],
+            StringIO(df.to_json(orient=orient)), orient=orient, convert_dates=["x"]
         )
         if orient == "values":
             expected = DataFrame(data)
             if expected.iloc[:, 0].dtype == "datetime64[ns]":
+                # orient == "values" by default will write Timestamp objects out
+                # in milliseconds; these are internally stored in nanosecond,
+                # so divide to get where we need
+                # TODO: a to_epoch method would also solve; see GH 14772
                 expected.isetitem(0, expected.iloc[:, 0].astype(np.int64) // 1000000)
         elif orient == "split":
             expected = df
@@ -994,6 +996,7 @@ def test_date_unit(self, unit, datetime_frame):
         ],
     )
     def test_default_epoch_date_format_deprecated(self, df, warn):
+        # GH 57063
         msg = (
             "The default 'Epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."

From 36d3cf4ec1670cab53fa8744a1a7877c59458c73 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Tue, 16 Apr 2024 18:15:44 +0300
Subject: [PATCH 10/12] Code review suggestions

---
 doc/source/user_guide/io.rst                  |  8 ++----
 pandas/core/generic.py                        |  4 +--
 .../tests/io/json/test_json_table_schema.py   |  2 +-
 pandas/tests/io/json/test_pandas.py           | 26 +++++++++----------
 pandas/tests/io/test_gcs.py                   |  2 +-
 5 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/doc/source/user_guide/io.rst b/doc/source/user_guide/io.rst
index cf8e71fc582c6..49609a80d7e15 100644
--- a/doc/source/user_guide/io.rst
+++ b/doc/source/user_guide/io.rst
@@ -1952,14 +1952,13 @@ Writing in ISO date format, with microseconds:
 Writing to a file, with a date index and a date column:
 
 .. ipython:: python
-   :okwarning:
 
    dfj2 = dfj.copy()
    dfj2["date"] = pd.Timestamp("20130101")
    dfj2["ints"] = list(range(5))
    dfj2["bools"] = True
    dfj2.index = pd.date_range("20130101", periods=5)
-   dfj2.to_json("test.json")
+   dfj2.to_json("test.json", date_format="iso")
 
    with open("test.json") as fh:
        print(fh.read())
@@ -2132,10 +2131,9 @@ Preserve string indices:
 Dates written in nanoseconds need to be read back in nanoseconds:
 
 .. ipython:: python
-   :okwarning:
 
    from io import StringIO
-   json = dfj2.to_json(date_unit="ns")
+   json = dfj2.to_json(date_format="iso", date_unit="ns")
 
    # Try to parse timestamps as milliseconds -> Won't Work
    dfju = pd.read_json(StringIO(json), date_unit="ms")
@@ -2270,7 +2268,6 @@ other attributes. You can use the orient ``table`` to build
 a JSON string with two fields, ``schema`` and ``data``.
 
 .. ipython:: python
-   :okwarning:
 
    df = pd.DataFrame(
        {
@@ -2380,7 +2377,6 @@ the preservation of metadata such as dtypes and index names in a
 round-trippable manner.
 
 .. ipython:: python
-   :okwarning:
 
    df = pd.DataFrame(
        {
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 3999d94873e74..64bc29f13dabf 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2542,7 +2542,7 @@ def to_json(
             )
             if any(lib.is_np_dtype(dtype, "mM") for dtype in dtypes):
                 warnings.warn(
-                    "The default 'Epoch' date format is deprecated and will be removed "
+                    "The default 'epoch' date format is deprecated and will be removed "
                     "in a future version, please use 'iso' date format instead.",
                     FutureWarning,
                     stacklevel=find_stack_level(),
@@ -2550,7 +2550,7 @@ def to_json(
         elif date_format == "epoch":
             # GH#57063
             warnings.warn(
-                "'Epoch' date format is deprecated and will be removed in a future "
+                "'epoch' date format is deprecated and will be removed in a future "
                 "version, please use 'iso' date format instead.",
                 FutureWarning,
                 stacklevel=find_stack_level(),
diff --git a/pandas/tests/io/json/test_json_table_schema.py b/pandas/tests/io/json/test_json_table_schema.py
index e9ff96d7f182a..4fa5d6e480ed2 100644
--- a/pandas/tests/io/json/test_json_table_schema.py
+++ b/pandas/tests/io/json/test_json_table_schema.py
@@ -456,7 +456,7 @@ def test_date_format_raises(self, df_table):
             "Schema requires dates to be formatted with `date_format='iso'`"
         )
         warning_msg = (
-            "'Epoch' date format is deprecated and will be removed in a future "
+            "'epoch' date format is deprecated and will be removed in a future "
             "version, please use 'iso' date format instead."
         )
         with pytest.raises(ValueError, match=error_msg):
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index 0bce482de5a79..e3ecf5dc5f18a 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -763,7 +763,7 @@ def test_series_with_dtype(self):
     def test_series_with_dtype_datetime(self, dtype, expected):
         s = Series(["2000-01-01"], dtype="datetime64[ns]")
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -814,7 +814,7 @@ def test_convert_dates(self, datetime_series, datetime_frame):
         df["date"] = Timestamp("20130101").as_unit("ns")
 
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -859,7 +859,7 @@ def test_date_index_and_values(self, date_format, as_object, date_typ):
             )
 
         msg = (
-            "'Epoch' date format is deprecated and will be removed in a future "
+            "'epoch' date format is deprecated and will be removed in a future "
             "version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(expected_warning, match=msg):
@@ -962,7 +962,7 @@ def test_date_unit(self, unit, datetime_frame):
         df.iloc[4, dl] = pd.NaT
 
         msg = (
-            "'Epoch' date format is deprecated and will be removed in a future "
+            "'epoch' date format is deprecated and will be removed in a future "
             "version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -998,7 +998,7 @@ def test_date_unit(self, unit, datetime_frame):
     def test_default_epoch_date_format_deprecated(self, df, warn):
         # GH 57063
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(warn, match=msg):
@@ -1074,7 +1074,7 @@ def test_doc_example(self):
         dfj2.index = date_range("20130101", periods=5)
 
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -1116,7 +1116,7 @@ def test_timedelta(self):
         assert ser.dtype == "timedelta64[ns]"
 
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -1145,7 +1145,7 @@ def test_timedelta2(self):
             }
         )
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -1190,7 +1190,7 @@ def test_timedelta_to_json(self, as_object, date_format, timedelta_typ):
             expected = expected.replace("}", ',"a":"a"}')
 
         msg = (
-            "'Epoch' date format is deprecated and will be removed in a future "
+            "'epoch' date format is deprecated and will be removed in a future "
             "version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(expected_warning, match=msg):
@@ -1208,7 +1208,7 @@ def test_timedelta_to_json_fractional_precision(self, as_object, timedelta_typ):
             warn = None
 
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(warn, match=msg):
@@ -1295,7 +1295,7 @@ def test_datetime_tz(self):
         df_naive = df.copy()
         df_naive["A"] = tz_naive
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -1571,7 +1571,7 @@ def test_to_json_from_json_columns_dtypes(self, orient):
             }
         )
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
@@ -1771,7 +1771,7 @@ def test_timedelta_as_label(self, date_format, key):
             expected_warning = FutureWarning
 
         msg = (
-            "'Epoch' date format is deprecated and will be removed in a future "
+            "'epoch' date format is deprecated and will be removed in a future "
             "version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(expected_warning, match=msg):
diff --git a/pandas/tests/io/test_gcs.py b/pandas/tests/io/test_gcs.py
index c4617d4eaed5c..4b2be41d0c9f9 100644
--- a/pandas/tests/io/test_gcs.py
+++ b/pandas/tests/io/test_gcs.py
@@ -79,7 +79,7 @@ def test_to_read_gcs(gcs_buffer, format, monkeypatch, capsys):
         df2 = read_excel(path, parse_dates=["dt"], index_col=0)
     elif format == "json":
         msg = (
-            "The default 'Epoch' date format is deprecated and will be removed "
+            "The default 'epoch' date format is deprecated and will be removed "
             "in a future version, please use 'iso' date format instead."
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):

From 50d6d998dcf69ff5767dca438c4510d5d959009c Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Tue, 16 Apr 2024 20:50:38 +0300
Subject: [PATCH 11/12] Stop use of filterwarnings

---
 doc/source/whatsnew/v3.0.0.rst      |  2 +-
 pandas/core/generic.py              |  4 ++--
 pandas/tests/io/json/test_pandas.py | 26 +++++++++++++++++++++-----
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 74b95479d347e..b3224b52663cc 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -182,7 +182,7 @@ Other Deprecations
 - Deprecated :meth:`Timestamp.utcnow`, use ``Timestamp.now("UTC")`` instead (:issue:`56680`)
 - Deprecated allowing non-keyword arguments in :meth:`Series.to_markdown` except ``buf``. (:issue:`57280`)
 - Deprecated allowing non-keyword arguments in :meth:`Series.to_string` except ``buf``. (:issue:`57280`)
-- Deprecated using ``epoch`` date format in :meth:`DataFrame.to_json` and :meth:`Series.to_json`, use ``iso`` instead.
+- Deprecated using ``epoch`` date format in :meth:`DataFrame.to_json` and :meth:`Series.to_json`, use ``iso`` instead. (:issue:`57063`)
 -
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 64bc29f13dabf..7240fab260abd 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2536,9 +2536,9 @@ def to_json(
         elif date_format is None:
             date_format = "epoch"
             dtypes = (
-                self.dtypes.values
+                self.dtypes
                 if self.ndim == 2
-                else np.array([self.dtype], dtype=object)
+                else [self.dtype]
             )
             if any(lib.is_np_dtype(dtype, "mM") for dtype in dtypes):
                 warnings.warn(
diff --git a/pandas/tests/io/json/test_pandas.py b/pandas/tests/io/json/test_pandas.py
index e3ecf5dc5f18a..c4065ea01988f 100644
--- a/pandas/tests/io/json/test_pandas.py
+++ b/pandas/tests/io/json/test_pandas.py
@@ -123,7 +123,6 @@ def test_frame_non_unique_index_raises(self, orient):
         with pytest.raises(ValueError, match=msg):
             df.to_json(orient=orient)
 
-    @pytest.mark.filterwarnings("ignore::FutureWarning")
     @pytest.mark.parametrize("orient", ["split", "values"])
     @pytest.mark.parametrize(
         "data",
@@ -137,9 +136,18 @@ def test_frame_non_unique_index_raises(self, orient):
     def test_frame_non_unique_columns(self, orient, data):
         df = DataFrame(data, index=[1, 2], columns=["x", "x"])
 
-        result = read_json(
-            StringIO(df.to_json(orient=orient)), orient=orient, convert_dates=["x"]
+        expected_warning = None
+        msg = (
+            "The default 'epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
         )
+        if df.iloc[:, 0].dtype == "datetime64[ns]":
+            expected_warning = FutureWarning
+
+        with tm.assert_produces_warning(expected_warning, match=msg):
+            result = read_json(
+                StringIO(df.to_json(orient=orient)), orient=orient, convert_dates=["x"]
+            )
         if orient == "values":
             expected = DataFrame(data)
             if expected.iloc[:, 0].dtype == "datetime64[ns]":
@@ -2001,14 +2009,22 @@ def test_to_s3(self, s3_public_bucket, s3so):
             timeout -= 0.1
             assert timeout > 0, "Timed out waiting for file to appear on moto"
 
-    @pytest.mark.filterwarnings("ignore::FutureWarning")
     def test_json_pandas_nulls(self, nulls_fixture, request):
         # GH 31615
         if isinstance(nulls_fixture, Decimal):
             mark = pytest.mark.xfail(reason="not implemented")
             request.applymarker(mark)
 
-        result = DataFrame([[nulls_fixture]]).to_json()
+        expected_warning = None
+        msg = (
+            "The default 'epoch' date format is deprecated and will be removed "
+            "in a future version, please use 'iso' date format instead."
+        )
+        if nulls_fixture is pd.NaT:
+            expected_warning = FutureWarning
+
+        with tm.assert_produces_warning(expected_warning, match=msg):
+            result = DataFrame([[nulls_fixture]]).to_json()
         assert result == '{"0":{"0":null}}'
 
     def test_readjson_bool_series(self):

From 8e4b95c3b374ee7d4ae5a6637e30d0c0dd75e408 Mon Sep 17 00:00:00 2001
From: Abdulaziz Aloqeely <52792999+DAzVise@users.noreply.github.com>
Date: Tue, 16 Apr 2024 20:54:31 +0300
Subject: [PATCH 12/12] Make pre-commit happy

---
 pandas/core/generic.py | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 7240fab260abd..32c955779763e 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2535,11 +2535,7 @@ def to_json(
             date_format = "iso"
         elif date_format is None:
             date_format = "epoch"
-            dtypes = (
-                self.dtypes
-                if self.ndim == 2
-                else [self.dtype]
-            )
+            dtypes = self.dtypes if self.ndim == 2 else [self.dtype]
             if any(lib.is_np_dtype(dtype, "mM") for dtype in dtypes):
                 warnings.warn(
                     "The default 'epoch' date format is deprecated and will be removed "