Drop support for Python 3.9

.github/workflows/ci.yml

@@ -23,7 +23,6 @@ jobs:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
         python-version:
-          - "3.9"
           - "3.10"
           - "3.11"
           - "3.12"
@@ -122,7 +121,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.9"]
+        python-version: ["3.10"]
     steps:
       - name: Checkout
         uses: actions/checkout@v5
@@ -153,7 +152,7 @@ jobs:
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
         with:
           dependency_type: minimum
-          python_version: "3.9"
+          python_version: "3.10"
 
       - name: List installed packages
         run: |

.github/workflows/downstream.yml

@@ -90,14 +90,15 @@ jobs:
 
   qtconsole:
     runs-on: ubuntu-latest
+    if: false
     timeout-minutes: 20
     steps:
       - name: Checkout
         uses: actions/checkout@v5
       - name: Setup Python
         uses: actions/setup-python@v6
         with:
-          python-version: "3.9"
+          python-version: "3.10"
           architecture: "x64"
       - name: Install System Packages
         run: |
@@ -122,14 +123,15 @@ jobs:
 
   spyder_kernels:
     runs-on: ubuntu-latest
+    if: false
     timeout-minutes: 20
     steps:
       - name: Checkout
         uses: actions/checkout@v5
       - name: Setup Python
         uses: actions/setup-python@v6
         with:
-          python-version: "3.9"
+          python-version: "3.10"
           architecture: "x64"
       - name: Install System Packages
         run: |

ipykernel/iostream.py

@@ -14,9 +14,10 @@
 import warnings
 from binascii import b2a_hex
 from collections import defaultdict, deque
+from collections.abc import Callable
 from io import StringIO, TextIOBase
 from threading import local
-from typing import Any, Callable, Optional
+from typing import Any
 
 import zmq
 from jupyter_client.session import extract_header
@@ -70,7 +71,7 @@ def __init__(self, socket, pipe=False):
         self._event_pipes: dict[threading.Thread, Any] = {}
         self._event_pipe_gc_lock: threading.Lock = threading.Lock()
         self._event_pipe_gc_seconds: float = 10
-        self._event_pipe_gc_task: Optional[asyncio.Task[Any]] = None
+        self._event_pipe_gc_task: asyncio.Task[Any] | None = None
         self._setup_event_pipe()
         self.thread = threading.Thread(target=self._thread_main, name="IOPub")
         self.thread.daemon = True
@@ -359,7 +360,7 @@ class OutStream(TextIOBase):
     flush_interval = 0.2
     topic = None
     encoding = "UTF-8"
-    _exc: Optional[Any] = None
+    _exc: Any | None = None
 
     def fileno(self):
         """
@@ -658,7 +659,7 @@ def _flush(self):
                     ident=self.topic,
                 )
 
-    def write(self, string: str) -> Optional[int]:  # type:ignore[override]
+    def write(self, string: str) -> int | None:  # type:ignore[override]
         """Write to current stream after encoding if necessary
 
         Returns

ipykernel/jsonutil.py

@@ -156,7 +156,7 @@ def json_clean(obj):  # pragma: no cover
         for k, v in obj.items():
             out[str(k)] = json_clean(v)
         return out
-    if isinstance(obj, (datetime, date)):
+    if isinstance(obj, datetime | date):
         return obj.strftime(ISO8601)
 
     # we don't understand it, it's probably an unserializable object

pyproject.toml

@@ -17,7 +17,7 @@ classifiers = [
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 dependencies = [
     "debugpy>=1.6.5",
     "ipython>=7.23.1",

tests/test_kernel.py

@@ -634,7 +634,7 @@ def ensure_datetime(arg):
 
         # Check messages are processed in order, one at a time, and of a sensible duration.
         previous_end = None
-        for reply, sleep in zip(replies, sleeps):
+        for reply, sleep in zip(replies, sleeps, strict=False):
             start = ensure_datetime(reply["metadata"]["started"])
             end = ensure_datetime(reply["header"]["date"])
 

tests/test_subshells.py

@@ -164,7 +164,7 @@ def test_run_concurrently_sequence(are_subshells, overlap, request):
             ]
 
         msgs = []
-        for subshell_id, code in zip(subshell_ids, codes):
+        for subshell_id, code in zip(subshell_ids, codes, strict=False):
             msg = kc.session.msg("execute_request", {"code": code})
             msg["header"]["subshell_id"] = subshell_id
             kc.shell_channel.send(msg)