require Python 3.9

.github/workflows/tests.yml

@@ -24,10 +24,8 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: ["3.8", "3.13"]
+        python-version: ["3.9", "3.13"]
         include:
-          - os: ubuntu-latest
-            python-version: "3.9"
           - os: ubuntu-latest
             python-version: "3.10"
           - os: ubuntu-latest

pyproject.toml

@@ -20,7 +20,7 @@ classifiers = [
     "Programming Language :: Python",
     "Typing :: Typed",
 ]
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dynamic = ["version"]
 
 [project.urls]
@@ -86,7 +86,7 @@ build = [
 
 [tool.mypy]
 files = "traitlets"
-python_version = "3.8"
+python_version = "3.9"
 strict = true
 enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]
 pretty = true

tests/test_typing.py

@@ -407,27 +407,27 @@ class T(HasTraits):
         otcp = TCPAddress(None, allow_none=True)
 
     t = T()
-    reveal_type(t.tcp)  # R: Tuple[builtins.str, builtins.int]
+    reveal_type(t.tcp)  # R: tuple[builtins.str, builtins.int]
     reveal_type(
-        T.tcp  # R: traitlets.traitlets.TCPAddress[Tuple[builtins.str, builtins.int], Tuple[builtins.str, builtins.int]]
+        T.tcp  # R: traitlets.traitlets.TCPAddress[tuple[builtins.str, builtins.int], tuple[builtins.str, builtins.int]]
     )
     reveal_type(
-        T.tcp.tag(  # R:traitlets.traitlets.TCPAddress[Tuple[builtins.str, builtins.int], Tuple[builtins.str, builtins.int]]
+        T.tcp.tag(  # R:traitlets.traitlets.TCPAddress[tuple[builtins.str, builtins.int], tuple[builtins.str, builtins.int]]
             sync=True
         )
     )
-    reveal_type(t.otcp)  # R: Union[Tuple[builtins.str, builtins.int], None]
+    reveal_type(t.otcp)  # R: Union[tuple[builtins.str, builtins.int], None]
     reveal_type(
-        T.otcp  # R: traitlets.traitlets.TCPAddress[Union[Tuple[builtins.str, builtins.int], None], Union[Tuple[builtins.str, builtins.int], None]]
+        T.otcp  # R: traitlets.traitlets.TCPAddress[Union[tuple[builtins.str, builtins.int], None], Union[tuple[builtins.str, builtins.int], None]]
     )
     reveal_type(
-        T.otcp.tag(  # R: traitlets.traitlets.TCPAddress[Union[Tuple[builtins.str, builtins.int], None], Union[Tuple[builtins.str, builtins.int], None]]
+        T.otcp.tag(  # R: traitlets.traitlets.TCPAddress[Union[tuple[builtins.str, builtins.int], None], Union[tuple[builtins.str, builtins.int], None]]
             sync=True
         )
     )
-    t.tcp = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Tuple[str, int]")  [assignment]
-    t.otcp = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Optional[Tuple[str, int]]")  [assignment]
-    t.tcp = None  # E: Incompatible types in assignment (expression has type "None", variable has type "Tuple[str, int]")  [assignment]
+    t.tcp = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "tuple[str, int]")  [assignment]
+    t.otcp = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Optional[tuple[str, int]]")  [assignment]
+    t.tcp = None  # E: Incompatible types in assignment (expression has type "None", variable has type "tuple[str, int]")  [assignment]
 
 
 @pytest.mark.mypy_testing

traitlets/_version.py

@@ -4,7 +4,6 @@
 from __future__ import annotations
 
 import re
-from typing import List
 
 # Version string must appear intact for hatch versioning
 __version__ = "5.14.3"
@@ -13,7 +12,7 @@
 pattern = r"(?P<major>\d+).(?P<minor>\d+).(?P<patch>\d+)(?P<rest>.*)"
 match = re.match(pattern, __version__)
 assert match is not None
-parts: List[object] = [int(match[part]) for part in ["major", "minor", "patch"]]
+parts: list[object] = [int(match[part]) for part in ["major", "minor", "patch"]]
 if match["rest"]:
     parts.append(match["rest"])
 version_info = tuple(parts)

traitlets/tests/utils.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
 import sys
+from collections.abc import Sequence
 from subprocess import PIPE, Popen
-from typing import Any, Sequence
+from typing import Any
 
 
 def get_output_error_code(cmd: str | Sequence[str]) -> tuple[str, str, Any]:

traitlets/utils/__init__.py

@@ -2,7 +2,7 @@
 
 import os
 import pathlib
-from typing import Sequence
+from collections.abc import Sequence
 
 
 # vestigal things from IPython_genutils.

traitlets/utils/decorators.py

@@ -3,7 +3,7 @@
 
 import copy
 from inspect import Parameter, Signature, signature
-from typing import Any, Type, TypeVar
+from typing import Any, TypeVar
 
 from ..traitlets import HasTraits, Undefined
 
@@ -16,7 +16,7 @@ def _get_default(value: Any) -> Any:
 T = TypeVar("T", bound=HasTraits)
 
 
-def signature_has_traits(cls: Type[T]) -> Type[T]:
+def signature_has_traits(cls: type[T]) -> type[T]:
     """Return a decorated class with a constructor signature that contain Trait names as kwargs."""
     traits = [
         (name, _get_default(value.default_value))

traitlets/utils/nested_update.py

@@ -2,10 +2,10 @@
 # Distributed under the terms of the Modified BSD License.
 from __future__ import annotations
 
-from typing import Any, Dict
+from typing import Any
 
 
-def nested_update(this: Dict[Any, Any], that: Dict[Any, Any]) -> Dict[Any, Any]:
+def nested_update(this: dict[Any, Any], that: dict[Any, Any]) -> dict[Any, Any]:
     """Merge two nested dictionaries.
 
     Effectively a recursive ``dict.update``.

traitlets/utils/text.py

@@ -6,7 +6,6 @@
 import re
 import textwrap
 from textwrap import indent as _indent
-from typing import List
 
 
 def indent(val: str) -> str:
@@ -32,7 +31,7 @@ def _dedent(text: str) -> str:
     return "\n".join([first, rest])
 
 
-def wrap_paragraphs(text: str, ncols: int = 80) -> List[str]:
+def wrap_paragraphs(text: str, ncols: int = 80) -> list[str]:
     """Wrap multiple paragraphs to fit a specified width.
 
     This is equivalent to textwrap.wrap, but with support for multiple