Fix mypy deps and support Python 3.8-3.12 (#862)

Author: blink1073

.github/workflows/tests.yml

@@ -24,7 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: ["3.7", "3.11"]
+        python-version: ["3.8", "3.12"]
         include:
           - os: windows-latest
             python-version: "3.9"
@@ -33,7 +33,7 @@ jobs:
           - os: ubuntu-latest
             python-version: "3.10"
           - os: macos-latest
-            python-version: "3.8"
+            python-version: "3.11"
 
     steps:
       - uses: actions/checkout@v4
@@ -62,7 +62,7 @@ jobs:
           dependency_type: minimum
       - name: Run the unit tests
         run: |
-          hatch run test:nowarn || hatch run test:nowarn --lf
+          hatch run test:nowarn || hatch -v run test:nowarn --lf
 
   test_lint:
     name: Test Lint

pyproject.toml

@@ -18,12 +18,11 @@ classifiers = [
     "Programming Language :: Python :: 3",
 ]
 urls = {Homepage = "https://github.com/ipython/traitlets"}
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 dynamic = ["version"]
-dependencies = ["typing_extensions>=4.0.1"]
 
 [project.optional-dependencies]
-test = ["pytest>=7.0,<7.5", "pytest-mock", "pre-commit", "argcomplete>=2.0", "pytest-mypy-testing", "mypy @ git+https://github.com/python/mypy.git@cb1d1a0baba37f35268cb605b7345726f257f960#egg=mypy"]
+test = ["pytest>=7.0,<7.5", "pytest-mock", "pre-commit", "argcomplete>=3.0.3", "pytest-mypy-testing", "mypy>=1.5.1"]
 docs = [
     "myst-parser",
     "pydata-sphinx-theme",
@@ -56,7 +55,6 @@ nowarn = "test -W default {args}"
 
 [tool.hatch.envs.typing]
 features = ["test"]
-dependencies = ["mypy @ git+https://github.com/python/mypy.git@cb1d1a0baba37f35268cb605b7345726f257f960#egg=mypy"]
 [tool.hatch.envs.typing.scripts]
 test = "mypy --install-types --non-interactive {args:.}"
 
@@ -76,6 +74,7 @@ fmt = [
 ]
 
 [tool.mypy]
+python_version = "3.8"
 check_untyped_defs = true
 disallow_any_generics = true
 disallow_incomplete_defs = true

traitlets/config/application.py

@@ -444,7 +444,7 @@ def _show_config_json_changed(self, change):
     def _show_config_changed(self, change):
         if change.new:
             self._save_start = self.start
-            self.start = self.start_show_config  # type:ignore[assignment]
+            self.start = self.start_show_config  # type:ignore[method-assign]
 
     def __init__(self, **kwargs):
         SingletonConfigurable.__init__(self, **kwargs)

traitlets/tests/test_typing.py

@@ -1,5 +1,6 @@
+from __future__ import annotations
+
 import typing
-from typing import Optional
 
 import pytest
 
@@ -63,7 +64,7 @@ class T(HasTraits):
 def mypy_int_typing():
     class T(HasTraits):
         i: Int[int, int] = Int(42).tag(sync=True)
-        oi: Int[Optional[int], Optional[int]] = Int(42, allow_none=True).tag(sync=True)
+        oi: Int[int | None, int | None] = Int(42, allow_none=True).tag(sync=True)
 
     t = T()
     reveal_type(Int(True))  # R: traitlets.traitlets.Int[builtins.int, builtins.int]