From 9b331e252620fb2835ade222bc65714960420885 Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 11:17:21 +1000
Subject: [PATCH 1/9] Add orjson_packer and orjson_unpacker to speed up
 serialization of session messages.

---
 CHANGELOG.md              |  1 +
 jupyter_client/session.py | 98 ++++++++++++++++++---------------------
 pyproject.toml            |  1 +
 tests/test_session.py     | 69 ++++++++++++++++++++-------
 4 files changed, 100 insertions(+), 69 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 12caeba0..fed08eb4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 ### Enhancements made
 
 - Support psutil for finding network addresses [#1033](https://github.com/jupyter/jupyter_client/pull/1033) ([@juliangilbey](https://github.com/juliangilbey))
+- Add new functions `orjson_packer` and `orjson_unpacker`.
 
 ### Bugs fixed
 
diff --git a/jupyter_client/session.py b/jupyter_client/session.py
index c387cd06..92f8829d 100644
--- a/jupyter_client/session.py
+++ b/jupyter_client/session.py
@@ -32,6 +32,7 @@
 from traitlets import (
     Any,
     Bool,
+    Callable,
     CBytes,
     CUnicode,
     Dict,
@@ -124,6 +125,28 @@ def json_unpacker(s: str | bytes) -> t.Any:
     return json.loads(s)
 
 
+try:
+    import orjson  # type:ignore[import-not-found]
+except ModuleNotFoundError:
+    orjson = None
+    _default_packer_unpacker = "json", "json"
+    _default_pack_unpack = (json_packer, json_unpacker)
+else:
+
+    def orjson_packer(obj: t.Any) -> bytes:
+        """Convert a json object to a bytes using orjson with a fallback to json_packer."""
+        try:
+            return orjson.dumps(
+                obj, default=json_default, option=orjson.OPT_NAIVE_UTC | orjson.OPT_UTC_Z
+            )
+        except (TypeError, ValueError):
+            return json_packer(obj)
+
+    orjson_unpacker = orjson.loads
+    _default_packer_unpacker = "orjson", "orjson"
+    _default_pack_unpack = (orjson_packer, orjson_unpacker)
+
+
 def pickle_packer(o: t.Any) -> bytes:
     """Pack an object using the pickle module."""
     return pickle.dumps(squash_dates(o), PICKLE_PROTOCOL)
@@ -131,8 +154,6 @@ def pickle_packer(o: t.Any) -> bytes:
 
 pickle_unpacker = pickle.loads
 
-default_packer = json_packer
-default_unpacker = json_unpacker
 
 DELIM = b"<IDS|MSG>"
 # singleton dummy tracker, which will always report as done
@@ -350,48 +371,43 @@ class Session(Configurable):
         """,
     )
 
+    # serialization traits:
     packer = DottedObjectName(
-        "json",
+        _default_packer_unpacker[0],
         config=True,
         help="""The name of the packer for serializing messages.
             Should be one of 'json', 'pickle', or an import name
             for a custom callable serializer.""",
     )
-
-    @observe("packer")
-    def _packer_changed(self, change: t.Any) -> None:
-        new = change["new"]
-        if new.lower() == "json":
-            self.pack = json_packer
-            self.unpack = json_unpacker
-            self.unpacker = new
-        elif new.lower() == "pickle":
-            self.pack = pickle_packer
-            self.unpack = pickle_unpacker
-            self.unpacker = new
-        else:
-            self.pack = import_item(str(new))
-
     unpacker = DottedObjectName(
-        "json",
+        _default_packer_unpacker[1],
         config=True,
         help="""The name of the unpacker for unserializing messages.
         Only used with custom functions for `packer`.""",
     )
+    pack = Callable(_default_pack_unpack[0])  # the actual packer function
+    unpack = Callable(_default_pack_unpack[1])  # the actual unpacker function
 
-    @observe("unpacker")
-    def _unpacker_changed(self, change: t.Any) -> None:
+    @observe("packer", "unpacker")
+    def _packer_unpacker_changed(self, change: t.Any) -> None:
         new = change["new"]
-        if new.lower() == "json":
+        new_ = new.lower()
+        if new_ == "orjson" and orjson:
+            self.pack = orjson_packer
+            self.unpack = orjson_unpacker
+            self.packer = self.unpacker = new
+        elif new_ in ["json", "orjson"]:
             self.pack = json_packer
             self.unpack = json_unpacker
-            self.packer = new
-        elif new.lower() == "pickle":
+            self.packer = self.unpacker = new
+        elif new_ == "pickle":
             self.pack = pickle_packer
             self.unpack = pickle_unpacker
-            self.packer = new
+            self.packer = self.unpacker = new
         else:
-            self.unpack = import_item(str(new))
+            obj = import_item(str(new))
+            name = "pack" if change["name"] == "packer" else "unpack"
+            self.set_trait(name, obj)
 
     session = CUnicode("", config=True, help="""The UUID identifying this session.""")
 
@@ -416,8 +432,7 @@ def _session_changed(self, change: t.Any) -> None:
     metadata = Dict(
         {},
         config=True,
-        help="Metadata dictionary, which serves as the default top-level metadata dict for each "
-        "message.",
+        help="Metadata dictionary, which serves as the default top-level metadata dict for each message.",
     )
 
     # if 0, no adapting to do.
@@ -486,25 +501,6 @@ def _keyfile_changed(self, change: t.Any) -> None:
     # for protecting against sends from forks
     pid = Integer()
 
-    # serialization traits:
-
-    pack = Any(default_packer)  # the actual packer function
-
-    @observe("pack")
-    def _pack_changed(self, change: t.Any) -> None:
-        new = change["new"]
-        if not callable(new):
-            raise TypeError("packer must be callable, not %s" % type(new))
-
-    unpack = Any(default_unpacker)  # the actual packer function
-
-    @observe("unpack")
-    def _unpack_changed(self, change: t.Any) -> None:
-        # unpacker is not checked - it is assumed to be
-        new = change["new"]
-        if not callable(new):
-            raise TypeError("unpacker must be callable, not %s" % type(new))
-
     # thresholds:
     copy_threshold = Integer(
         2**16,
@@ -514,8 +510,7 @@ def _unpack_changed(self, change: t.Any) -> None:
     buffer_threshold = Integer(
         MAX_BYTES,
         config=True,
-        help="Threshold (in bytes) beyond which an object's buffer should be extracted to avoid "
-        "pickling.",
+        help="Threshold (in bytes) beyond which an object's buffer should be extracted to avoid pickling.",
     )
     item_threshold = Integer(
         MAX_ITEMS,
@@ -625,10 +620,7 @@ def _check_packers(self) -> None:
             unpacked = unpack(packed)
             assert unpacked == msg_list
         except Exception as e:
-            msg = (
-                f"unpacker '{self.unpacker}' could not handle output from packer"
-                f" '{self.packer}': {e}"
-            )
+            msg = f"unpacker '{self.unpacker}' could not handle output from packer '{self.packer}': {e}"
             raise ValueError(msg) from e
 
         # check datetime support
diff --git a/pyproject.toml b/pyproject.toml
index 27503497..36f3d281 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,6 +22,7 @@ requires-python = ">=3.9"
 dependencies = [
     "importlib_metadata>=4.8.3;python_version<\"3.10\"",
     "jupyter_core>=4.12,!=5.0.*",
+    "orjson>=3.10.18; implementation_name == 'cpython'",
     "python-dateutil>=2.8.2",
     "pyzmq>=23.0",
     "tornado>=6.2",
diff --git a/tests/test_session.py b/tests/test_session.py
index f30f44f4..0085b1ca 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -14,6 +14,7 @@
 import zmq
 from dateutil.tz import tzlocal
 from tornado import ioloop
+from traitlets import TraitError
 from zmq.eventloop.zmqstream import ZMQStream
 
 from jupyter_client import jsonutil
@@ -40,6 +41,14 @@ def session():
     return ss.Session()
 
 
+serializers = [
+    ("json", ss.json_packer, ss.json_unpacker),
+    ("pickle", ss.pickle_packer, ss.pickle_unpacker),
+]
+if ss.orjson:
+    serializers.append(("orjson", ss.orjson_packer, ss.orjson_unpacker))
+
+
 @pytest.mark.usefixtures("no_copy_threshold")
 class TestSession:
     def assertEqual(self, a, b):
@@ -63,7 +72,11 @@ def test_msg(self, session):
         self.assertEqual(msg["header"]["msg_type"], "execute")
         self.assertEqual(msg["msg_type"], "execute")
 
-    def test_serialize(self, session):
+    @pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
+    def test_serialize(self, session, packer, pack, unpack):
+        session.packer = packer
+        assert session.pack is pack
+        assert session.unpack is unpack
         msg = session.msg("execute", content=dict(a=10, b=1.1))
         msg_list = session.serialize(msg, ident=b"foo")
         ident, msg_list = session.feed_identities(msg_list)
@@ -233,16 +246,16 @@ async def test_send(self, session):
     def test_args(self, session):
         """initialization arguments for Session"""
         s = session
-        self.assertTrue(s.pack is ss.default_packer)
-        self.assertTrue(s.unpack is ss.default_unpacker)
+        assert s.pack is ss._default_pack_unpack[0]
+        assert s.unpack is ss._default_pack_unpack[1]
         self.assertEqual(s.username, os.environ.get("USER", "username"))
 
         s = ss.Session()
         self.assertEqual(s.username, os.environ.get("USER", "username"))
 
-        with pytest.raises(TypeError):
+        with pytest.raises(TraitError):
             ss.Session(pack="hi")
-        with pytest.raises(TypeError):
+        with pytest.raises(TraitError):
             ss.Session(unpack="hi")
         u = str(uuid.uuid4())
         s = ss.Session(username="carrot", session=u)
@@ -490,11 +503,6 @@ async def test_send_raw(self, session):
         B.close()
         ctx.term()
 
-    def test_set_packer(self, session):
-        s = session
-        s.packer = "json"
-        s.unpacker = "json"
-
     def test_clone(self, session):
         s = session
         s._add_digest("initial")
@@ -514,14 +522,43 @@ def test_squash_unicode():
     assert ss.squash_unicode("hi") == b"hi"
 
 
-def test_json_packer():
-    ss.json_packer(dict(a=1))
-    with pytest.raises(ValueError):
-        ss.json_packer(dict(a=ss.Session()))
-    ss.json_packer(dict(a=datetime(2021, 4, 1, 12, tzinfo=tzlocal())))
+@pytest.mark.parametrize(
+    ["description", "data"],
+    [
+        ("dict", [{"a": 1}, [{"a": 1}]]),
+        ("infinite", [math.inf, ["inf", None]]),
+        ("datetime", [datetime(2021, 4, 1, 12, tzinfo=tzlocal()), ["2021-04-01T12:00:00+11:00"]]),
+    ],
+)
+@pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
+def test_serialize_objects(packer, pack, unpack, description, data):
+    data_in, data_out_options = data
     with warnings.catch_warnings():
         warnings.simplefilter("ignore")
-        ss.json_packer(dict(a=math.inf))
+        value = pack(data_in)
+    unpacked = unpack(value)
+    if (description == "infinite") and (packer == "pickle"):
+        assert math.isinf(unpacked)
+        return
+    assert unpacked in data_out_options
+
+
+@pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
+def test_cannot_serialize(session, packer, pack, unpack):
+    data = {"a": session}
+    with pytest.raises((TypeError, ValueError)):
+        pack(data)
+
+
+@pytest.mark.parametrize("mode", ["packer", "unpacker"])
+@pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
+def test_packer_unpacker(session, packer, pack, unpack, mode):
+    s: ss.Session = session
+    s.set_trait(mode, packer)
+    assert s.pack is pack
+    assert s.unpack is unpack
+    mode_reverse = "unpacker" if mode == "packer" else "packer"
+    assert getattr(s, mode_reverse) == packer
 
 
 def test_message_cls():

From 6ec7306eb1d070b2ee34d8d3a66e42895cab1e67 Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 11:53:50 +1000
Subject: [PATCH 2/9] Refactor orjson packer to use functools.partial.

---
 jupyter_client/session.py | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/jupyter_client/session.py b/jupyter_client/session.py
index 92f8829d..5883cbdb 100644
--- a/jupyter_client/session.py
+++ b/jupyter_client/session.py
@@ -132,16 +132,11 @@ def json_unpacker(s: str | bytes) -> t.Any:
     _default_packer_unpacker = "json", "json"
     _default_pack_unpack = (json_packer, json_unpacker)
 else:
+    import functools
 
-    def orjson_packer(obj: t.Any) -> bytes:
-        """Convert a json object to a bytes using orjson with a fallback to json_packer."""
-        try:
-            return orjson.dumps(
-                obj, default=json_default, option=orjson.OPT_NAIVE_UTC | orjson.OPT_UTC_Z
-            )
-        except (TypeError, ValueError):
-            return json_packer(obj)
-
+    orjson_packer = functools.partial(
+        orjson.dumps, default=json_default, option=orjson.OPT_NAIVE_UTC | orjson.OPT_UTC_Z
+    )
     orjson_unpacker = orjson.loads
     _default_packer_unpacker = "orjson", "orjson"
     _default_pack_unpack = (orjson_packer, orjson_unpacker)

From c92b9c74eb5127a10322dacc18bbf2927bf42c17 Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 14:16:35 +1000
Subject: [PATCH 3/9] Add msgpack support for message serialization in Session

---
 CHANGELOG.md              |  2 +-
 jupyter_client/session.py | 20 ++++++++++++++++----
 tests/test_session.py     |  6 ++++--
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fed08eb4..1e199a88 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,7 +9,7 @@
 ### Enhancements made
 
 - Support psutil for finding network addresses [#1033](https://github.com/jupyter/jupyter_client/pull/1033) ([@juliangilbey](https://github.com/juliangilbey))
-- Add new functions `orjson_packer` and `orjson_unpacker`.
+- Add new functions `orjson_packer`, `orjson_unpacker`, `msgpack_packer` and `msgpack_unpacker`
 
 ### Bugs fixed
 
diff --git a/jupyter_client/session.py b/jupyter_client/session.py
index 5883cbdb..2adfaa0f 100644
--- a/jupyter_client/session.py
+++ b/jupyter_client/session.py
@@ -12,6 +12,7 @@
 # Distributed under the terms of the Modified BSD License.
 from __future__ import annotations
 
+import functools
 import hashlib
 import hmac
 import json
@@ -132,8 +133,6 @@ def json_unpacker(s: str | bytes) -> t.Any:
     _default_packer_unpacker = "json", "json"
     _default_pack_unpack = (json_packer, json_unpacker)
 else:
-    import functools
-
     orjson_packer = functools.partial(
         orjson.dumps, default=json_default, option=orjson.OPT_NAIVE_UTC | orjson.OPT_UTC_Z
     )
@@ -141,6 +140,15 @@ def json_unpacker(s: str | bytes) -> t.Any:
     _default_packer_unpacker = "orjson", "orjson"
     _default_pack_unpack = (orjson_packer, orjson_unpacker)
 
+try:
+    import msgpack  # type:ignore[import-not-found]
+
+except ModuleNotFoundError:
+    msgpack = None
+else:
+    msgpack_packer = functools.partial(msgpack.packb, default=json_default)
+    msgpack_unpacker = msgpack.unpackb
+
 
 def pickle_packer(o: t.Any) -> bytes:
     """Pack an object using the pickle module."""
@@ -331,7 +339,7 @@ class Session(Configurable):
 
     debug : bool
         whether to trigger extra debugging statements
-    packer/unpacker : str : 'json', 'pickle' or import_string
+    packer/unpacker : str : 'orjson', 'json', 'pickle', 'msgpack' or import_string
         importstrings for methods to serialize message parts.  If just
         'json' or 'pickle', predefined JSON and pickle packers will be used.
         Otherwise, the entire importstring must be used.
@@ -399,6 +407,10 @@ def _packer_unpacker_changed(self, change: t.Any) -> None:
             self.pack = pickle_packer
             self.unpack = pickle_unpacker
             self.packer = self.unpacker = new
+        elif new_ == "msgpack":
+            self.pack = msgpack_packer
+            self.unpack = msgpack_unpacker
+            self.packer = self.unpacker = new
         else:
             obj = import_item(str(new))
             name = "pack" if change["name"] == "packer" else "unpack"
@@ -523,7 +535,7 @@ def __init__(self, **kwargs: t.Any) -> None:
 
         debug : bool
             whether to trigger extra debugging statements
-        packer/unpacker : str : 'json', 'pickle' or import_string
+        packer/unpacker : str : 'orjson', 'json', 'pickle', 'msgpack' or import_string
             importstrings for methods to serialize message parts.  If just
             'json' or 'pickle', predefined JSON and pickle packers will be used.
             Otherwise, the entire importstring must be used.
diff --git a/tests/test_session.py b/tests/test_session.py
index 0085b1ca..34c0203d 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -47,6 +47,8 @@ def session():
 ]
 if ss.orjson:
     serializers.append(("orjson", ss.orjson_packer, ss.orjson_unpacker))
+if ss.msgpack:
+    serializers.append(("msgpack", ss.msgpack_packer, ss.msgpack_unpacker))
 
 
 @pytest.mark.usefixtures("no_copy_threshold")
@@ -537,7 +539,7 @@ def test_serialize_objects(packer, pack, unpack, description, data):
         warnings.simplefilter("ignore")
         value = pack(data_in)
     unpacked = unpack(value)
-    if (description == "infinite") and (packer == "pickle"):
+    if (description == "infinite") and (packer in ["pickle", "msgpack"]):
         assert math.isinf(unpacked)
         return
     assert unpacked in data_out_options
@@ -552,7 +554,7 @@ def test_cannot_serialize(session, packer, pack, unpack):
 
 @pytest.mark.parametrize("mode", ["packer", "unpacker"])
 @pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
-def test_packer_unpacker(session, packer, pack, unpack, mode):
+def test_pack_unpack(session, packer, pack, unpack, mode):
     s: ss.Session = session
     s.set_trait(mode, packer)
     assert s.pack is pack

From c03c7a0a84aeb2f511a8f63511496e6a73e9ea4b Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 20:35:04 +1000
Subject: [PATCH 4/9] Refactor packer/unpacker change handling for improved
 readability

---
 CHANGELOG.md              |  1 -
 jupyter_client/session.py | 31 ++++++++++++-------------------
 tests/test_session.py     |  6 +++++-
 3 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e199a88..12caeba0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,7 +9,6 @@
 ### Enhancements made
 
 - Support psutil for finding network addresses [#1033](https://github.com/jupyter/jupyter_client/pull/1033) ([@juliangilbey](https://github.com/juliangilbey))
-- Add new functions `orjson_packer`, `orjson_unpacker`, `msgpack_packer` and `msgpack_unpacker`
 
 ### Bugs fixed
 
diff --git a/jupyter_client/session.py b/jupyter_client/session.py
index 2adfaa0f..799b08d6 100644
--- a/jupyter_client/session.py
+++ b/jupyter_client/session.py
@@ -393,28 +393,21 @@ class Session(Configurable):
 
     @observe("packer", "unpacker")
     def _packer_unpacker_changed(self, change: t.Any) -> None:
-        new = change["new"]
-        new_ = new.lower()
-        if new_ == "orjson" and orjson:
-            self.pack = orjson_packer
-            self.unpack = orjson_unpacker
-            self.packer = self.unpacker = new
-        elif new_ in ["json", "orjson"]:
-            self.pack = json_packer
-            self.unpack = json_unpacker
-            self.packer = self.unpacker = new
-        elif new_ == "pickle":
-            self.pack = pickle_packer
-            self.unpack = pickle_unpacker
-            self.packer = self.unpacker = new
-        elif new_ == "msgpack":
-            self.pack = msgpack_packer
-            self.unpack = msgpack_unpacker
-            self.packer = self.unpacker = new
+        new = change["new"].lower()
+        if new == "orjson" and orjson:
+            self.pack, self.unpack = orjson_packer, orjson_unpacker
+        elif new == "json" or new == "orjson":
+            self.pack, self.unpack = json_packer, json_unpacker
+        elif new == "pickle":
+            self.pack, self.unpack = pickle_packer, pickle_unpacker
+        elif new == "msgpack" and msgpack:
+            self.pack, self.unpack = msgpack_packer, msgpack_unpacker
         else:
-            obj = import_item(str(new))
+            obj = import_item(str(change["new"]))
             name = "pack" if change["name"] == "packer" else "unpack"
             self.set_trait(name, obj)
+            return
+        self.packer = self.unpacker = change["new"]
 
     session = CUnicode("", config=True, help="""The UUID identifying this session.""")
 
diff --git a/tests/test_session.py b/tests/test_session.py
index 34c0203d..694f9922 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -524,12 +524,16 @@ def test_squash_unicode():
     assert ss.squash_unicode("hi") == b"hi"
 
 
+_sample_time = datetime(2021, 4, 1, 12, tzinfo=tzlocal())
+_sample_time_string = ss.json_default(_sample_time)
+
+
 @pytest.mark.parametrize(
     ["description", "data"],
     [
         ("dict", [{"a": 1}, [{"a": 1}]]),
         ("infinite", [math.inf, ["inf", None]]),
-        ("datetime", [datetime(2021, 4, 1, 12, tzinfo=tzlocal()), ["2021-04-01T12:00:00+11:00"]]),
+        ("datetime", [_sample_time, [_sample_time_string]]),
     ],
 )
 @pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)

From f4d15806f76f87076541e88ffa765d405035e132 Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 21:00:24 +1000
Subject: [PATCH 5/9] Fix test_serialize_objects datetime checks on ci to
 compare using datetime format.

---
 tests/test_session.py | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/tests/test_session.py b/tests/test_session.py
index 694f9922..c1c50f1c 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -524,16 +524,12 @@ def test_squash_unicode():
     assert ss.squash_unicode("hi") == b"hi"
 
 
-_sample_time = datetime(2021, 4, 1, 12, tzinfo=tzlocal())
-_sample_time_string = ss.json_default(_sample_time)
-
-
 @pytest.mark.parametrize(
     ["description", "data"],
     [
         ("dict", [{"a": 1}, [{"a": 1}]]),
         ("infinite", [math.inf, ["inf", None]]),
-        ("datetime", [_sample_time, [_sample_time_string]]),
+        ("datetime", [datetime(2021, 4, 1, 12, tzinfo=tzlocal()), []]),
     ],
 )
 @pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
@@ -545,8 +541,10 @@ def test_serialize_objects(packer, pack, unpack, description, data):
     unpacked = unpack(value)
     if (description == "infinite") and (packer in ["pickle", "msgpack"]):
         assert math.isinf(unpacked)
-        return
-    assert unpacked in data_out_options
+    elif description == "datetime":
+        assert data_in == datetime.fromisoformat(unpacked)
+    else:
+        assert unpacked in data_out_options
 
 
 @pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)

From fd29e5d8689c4e85223c83f6c61fd89332ceba76 Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 21:59:03 +1000
Subject: [PATCH 6/9] Fix datetime deserialization in test_serialize_objects to
 use dateutil.parser.isoparse

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

diff --git a/tests/test_session.py b/tests/test_session.py
index c1c50f1c..340ad4ed 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -10,6 +10,7 @@
 from datetime import datetime
 from unittest import mock
 
+import dateutil.parser
 import pytest
 import zmq
 from dateutil.tz import tzlocal
@@ -542,7 +543,7 @@ def test_serialize_objects(packer, pack, unpack, description, data):
     if (description == "infinite") and (packer in ["pickle", "msgpack"]):
         assert math.isinf(unpacked)
     elif description == "datetime":
-        assert data_in == datetime.fromisoformat(unpacked)
+        assert data_in == dateutil.parser.isoparse(unpacked)
     else:
         assert unpacked in data_out_options
 

From cec22e6e97101f0b4393cbd0a8a00d3a7585c7e6 Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Mon, 9 Jun 2025 22:12:49 +1000
Subject: [PATCH 7/9] Add PicklingError to exception handling in
 test_cannot_serialize

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

diff --git a/tests/test_session.py b/tests/test_session.py
index 340ad4ed..257df5c8 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -8,6 +8,7 @@
 import uuid
 import warnings
 from datetime import datetime
+from pickle import PicklingError
 from unittest import mock
 
 import dateutil.parser
@@ -551,7 +552,7 @@ def test_serialize_objects(packer, pack, unpack, description, data):
 @pytest.mark.parametrize(["packer", "pack", "unpack"], serializers)
 def test_cannot_serialize(session, packer, pack, unpack):
     data = {"a": session}
-    with pytest.raises((TypeError, ValueError)):
+    with pytest.raises((TypeError, ValueError, PicklingError)):
         pack(data)
 
 

From 452103bafa17573206b77d78062b2c0dea2bc04c Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Tue, 10 Jun 2025 07:23:48 +1000
Subject: [PATCH 8/9] Update api docs

---
 docs/api/jupyter_client.asynchronous.rst |  4 +--
 docs/api/jupyter_client.blocking.rst     |  4 +--
 docs/api/jupyter_client.ioloop.rst       |  6 ++--
 docs/api/jupyter_client.provisioning.rst |  8 ++---
 docs/api/jupyter_client.rst              | 46 ++++++++++++------------
 docs/api/jupyter_client.ssh.rst          |  6 ++--
 6 files changed, 37 insertions(+), 37 deletions(-)

diff --git a/docs/api/jupyter_client.asynchronous.rst b/docs/api/jupyter_client.asynchronous.rst
index 5fee3b81..7377df34 100644
--- a/docs/api/jupyter_client.asynchronous.rst
+++ b/docs/api/jupyter_client.asynchronous.rst
@@ -7,13 +7,13 @@ Submodules
 
 .. automodule:: jupyter_client.asynchronous.client
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 Module contents
 ---------------
 
 .. automodule:: jupyter_client.asynchronous
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
diff --git a/docs/api/jupyter_client.blocking.rst b/docs/api/jupyter_client.blocking.rst
index ba194cbf..e74eb840 100644
--- a/docs/api/jupyter_client.blocking.rst
+++ b/docs/api/jupyter_client.blocking.rst
@@ -7,13 +7,13 @@ Submodules
 
 .. automodule:: jupyter_client.blocking.client
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 Module contents
 ---------------
 
 .. automodule:: jupyter_client.blocking
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
diff --git a/docs/api/jupyter_client.ioloop.rst b/docs/api/jupyter_client.ioloop.rst
index 2c06a832..f1d9d909 100644
--- a/docs/api/jupyter_client.ioloop.rst
+++ b/docs/api/jupyter_client.ioloop.rst
@@ -7,19 +7,19 @@ Submodules
 
 .. automodule:: jupyter_client.ioloop.manager
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.ioloop.restarter
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 Module contents
 ---------------
 
 .. automodule:: jupyter_client.ioloop
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
diff --git a/docs/api/jupyter_client.provisioning.rst b/docs/api/jupyter_client.provisioning.rst
index 5a2de00f..80c431a7 100644
--- a/docs/api/jupyter_client.provisioning.rst
+++ b/docs/api/jupyter_client.provisioning.rst
@@ -7,25 +7,25 @@ Submodules
 
 .. automodule:: jupyter_client.provisioning.factory
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.provisioning.local_provisioner
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.provisioning.provisioner_base
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 Module contents
 ---------------
 
 .. automodule:: jupyter_client.provisioning
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
diff --git a/docs/api/jupyter_client.rst b/docs/api/jupyter_client.rst
index 336dcc2d..797ceae1 100644
--- a/docs/api/jupyter_client.rst
+++ b/docs/api/jupyter_client.rst
@@ -19,139 +19,139 @@ Submodules
 
 .. automodule:: jupyter_client.adapter
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.channels
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.channelsabc
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.client
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.clientabc
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.connect
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.consoleapp
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.jsonutil
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.kernelapp
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.kernelspec
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.kernelspecapp
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.launcher
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.localinterfaces
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.manager
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.managerabc
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.multikernelmanager
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.restarter
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.runapp
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.session
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.threaded
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.utils
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.win_interrupt
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 Module contents
 ---------------
 
 .. automodule:: jupyter_client
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
diff --git a/docs/api/jupyter_client.ssh.rst b/docs/api/jupyter_client.ssh.rst
index 06a1d9db..9ad3c79b 100644
--- a/docs/api/jupyter_client.ssh.rst
+++ b/docs/api/jupyter_client.ssh.rst
@@ -7,19 +7,19 @@ Submodules
 
 .. automodule:: jupyter_client.ssh.forward
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 
 .. automodule:: jupyter_client.ssh.tunnel
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:
 
 Module contents
 ---------------
 
 .. automodule:: jupyter_client.ssh
    :members:
-   :undoc-members:
    :show-inheritance:
+   :undoc-members:

From 7386b1db9f7a93c108905224029bc6334f00037c Mon Sep 17 00:00:00 2001
From: Alan Fleming <fleming79@gmail.com>
Date: Tue, 10 Jun 2025 14:12:16 +1000
Subject: [PATCH 9/9] Replace dateutil.parser.isoparse with jsonutil.parse_date
 in test_serialize_objects for datetime validation

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

diff --git a/tests/test_session.py b/tests/test_session.py
index 257df5c8..88117d05 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -11,7 +11,6 @@
 from pickle import PicklingError
 from unittest import mock
 
-import dateutil.parser
 import pytest
 import zmq
 from dateutil.tz import tzlocal
@@ -544,7 +543,7 @@ def test_serialize_objects(packer, pack, unpack, description, data):
     if (description == "infinite") and (packer in ["pickle", "msgpack"]):
         assert math.isinf(unpacked)
     elif description == "datetime":
-        assert data_in == dateutil.parser.isoparse(unpacked)
+        assert data_in == jsonutil.parse_date(unpacked)
     else:
         assert unpacked in data_out_options