Adopt ruff and address lint

.github/dependabot.yml

@@ -1,8 +1,10 @@
 version: 2
 updates:
-  # Set update schedule for GitHub Actions
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
-      # Check for updates to GitHub Actions every weekday
+      interval: "weekly"
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
       interval: "weekly"

.github/workflows/tests.yml

@@ -57,6 +57,19 @@ jobs:
         run: |
           hatch run test:nowarn || hatch run test:nowarn --lf
 
+  test_lint:
+    name: Test Lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
+      -  name: Run Linters
+         run: |
+          hatch run typing:test
+          hatch run lint:style
+          pipx run 'validate-pyproject[all]' pyproject.toml
+          pipx run doc8 --max-line-length=200
+
   test_docs:
     timeout-minutes: 10
     runs-on: ubuntu-latest
@@ -121,19 +134,11 @@ jobs:
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
 
-  pre_commit:
-    name: pre-commit
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
-      - uses: jupyterlab/maintainer-tools/.github/actions/pre-commit@v1
-
   tests_check: # This job does nothing and is only used for the branch protection
     if: always()
     needs:
       - tests
-      - pre_commit
+      - test_lint
       - test_docs
       - test_minimum_versions
       - test_prereleases

.pre-commit-config.yaml

@@ -1,85 +1,40 @@
+ci:
+  autoupdate_schedule: monthly
+
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.4.0
     hooks:
-      - id: debug-statements
-        stages: [manual]
+      - id: end-of-file-fixer
+      - id: check-case-conflict
+      - id: check-executables-have-shebangs
+      - id: requirements-txt-fixer
       - id: check-added-large-files
-        stages: [manual]
       - id: check-case-conflict
-        stages: [manual]
       - id: check-toml
-        stages: [manual]
       - id: check-yaml
-        stages: [manual]
+      - id: debug-statements
       - id: forbid-new-submodules
-        stages: [manual]
       - id: check-builtin-literals
-        stages: [manual]
-      - id: check-case-conflict
-        stages: [manual]
-      - id: check-executables-have-shebangs
-        stages: [manual]
-      - id: end-of-file-fixer
-      - id: requirements-txt-fixer
       - id: trailing-whitespace
 
-  - repo: https://github.com/psf/black
-    rev: 22.10.0
-    hooks:
-      - id: black
-        args: ["--line-length", "100"]
-
-  - repo: https://github.com/PyCQA/isort
-    rev: 5.10.1
-    hooks:
-      - id: isort
-        files: \.py$
-        args: [--profile=black]
-
-  - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.991
-    hooks:
-      - id: mypy
-        args: ["--config-file", "pyproject.toml"]
-        exclude: "traitlets/.*tests/.*.py"
-        additional_dependencies: [pytest, types-docutils, sphinx]
-        stages: [manual]
-
-  - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.10.1
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.19.2
     hooks:
-      - id: validate-pyproject
-        stages: [manual]
+      - id: check-github-workflows
 
   - repo: https://github.com/executablebooks/mdformat
     rev: 0.7.16
     hooks:
       - id: mdformat
 
-  - repo: https://github.com/asottile/pyupgrade
-    rev: v3.3.0
-    hooks:
-      - id: pyupgrade
-        args: [--py37-plus]
-
-  - repo: https://github.com/PyCQA/doc8
-    rev: v1.0.0
-    hooks:
-      - id: doc8
-        args: [--max-line-length=200]
-        stages: [manual]
-
-  - repo: https://github.com/john-hen/Flake8-pyproject
-    rev: 1.2.2
+  - repo: https://github.com/psf/black
+    rev: 22.10.0
     hooks:
-      - id: Flake8-pyproject
-        alias: flake8
-        additional_dependencies:
-          ["flake8-bugbear==22.6.22", "flake8-implicit-str-concat==0.2.0"]
-        stages: [manual]
+      - id: black
 
-  - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.19.2
+  - repo: https://github.com/charliermarsh/ruff-pre-commit
+    rev: v0.0.165
     hooks:
-      - id: check-github-workflows
+      - id: ruff
+        args: ["--fix"]

docs/source/conf.py

@@ -29,7 +29,7 @@
 
 # We load the ipython release info into a dict by explicit execution
 _release = {}  # type:ignore
-exec(
+exec(  # noqa
     compile(
         open(osp.join(ROOT, "traitlets/_version.py")).read(),
         "../../traitlets/_version.py",

docs/sphinxext/github.py

@@ -19,7 +19,7 @@
 
 from docutils import nodes, utils
 from docutils.parsers.rst.roles import set_classes
-from sphinx.util.logging import getLogger
+from sphinx.util.logging import getLogger  # type:ignore
 
 info = getLogger(__name__).info
 
@@ -41,7 +41,9 @@ def make_link_node(rawtext, app, type, slug, options):
         if not base.endswith("/"):
             base += "/"
     except AttributeError as err:
-        raise ValueError("github_project_url configuration value is not set (%s)" % str(err))
+        raise ValueError(
+            "github_project_url configuration value is not set (%s)" % str(err)
+        ) from err
 
     ref = base + type + "/" + slug + "/"
     set_classes(options)
@@ -147,7 +149,9 @@ def ghcommit_role(name, rawtext, text, lineno, inliner, options=None, content=No
         if not base.endswith("/"):
             base += "/"
     except AttributeError as err:
-        raise ValueError("github_project_url configuration value is not set (%s)" % str(err))
+        raise ValueError(
+            "github_project_url configuration value is not set (%s)" % str(err)
+        ) from err
 
     ref = base + text
     node = nodes.reference(rawtext, text[:6], refuri=ref, **options)

pyproject.toml

@@ -28,6 +28,8 @@ docs = [
     "pydata-sphinx-theme",
     "sphinx"
 ]
+lint = ["black>=22.6.0", "mdformat>0.7", "ruff>=0.0.156"]
+typing = ["mypy>=0.990"]
 
 [tool.hatch.version]
 path = "traitlets/_version.py"
@@ -50,6 +52,26 @@ dependencies = ["coverage", "pytest-cov"]
 test = "python -m pytest -vv --cov traitlets --cov-branch --cov-report term-missing:skip-covered {args}"
 nowarn = "test -W default {args}"
 
+[tool.hatch.envs.typing]
+features = ["test", "typing"]
+dependencies = ["mypy>=0.990"]
+[tool.hatch.envs.typing.scripts]
+test = "mypy --install-types --non-interactive {args:.}"
+
+[tool.hatch.envs.lint]
+features = ["lint"]
+[tool.hatch.envs.lint.scripts]
+style = [
+  "ruff {args:.}",
+  "black --check --diff {args:.}",
+  "mdformat --check {args:docs *.md}"
+]
+fmt = [
+  "black {args:.}",
+  "ruff --fix {args:.}",
+  "mdformat {args:docs *.md}"
+]
+
 [tool.mypy]
 check_untyped_defs = true
 disallow_any_generics = true
@@ -115,27 +137,69 @@ exclude_lines = [
 "@(abc\\.)?abstractmethod",
 ]
 
-[tool.flake8]
-ignore = "E501, W503, E402"
-builtins = "c, get_config"
-exclude = [
-    ".cache",
-    ".github",
-    "docs",
-    "setup.py",
+[tool.black]
+line-length = 100
+skip-string-normalization = true
+target-version = ["py37"]
+
+[tool.ruff]
+target-version = "py37"
+line-length = 100
+select = [
+  "A", "B", "C", "E", "F", "FBT", "I", "N", "Q", "RUF", "S", "T",
+  "UP", "W", "YTT",
 ]
-enable-extensions = "G"
-extend-ignore = [
-    "G001", "G002", "G004", "G200", "G201", "G202",
-    # black adds spaces around ':'
-    "E203",
+ignore = [
+  # Allow non-abstract empty methods in abstract base classes
+  "B027",
+  # Ignore McCabe complexity
+  "C901",
+  # Allow boolean positional values in function calls, like `dict.get(... True)`
+  "FBT003",
+  # Use of `assert` detected
+  "S101",
+  # Line too long
+  "E501",
+  # Relative imports are banned
+  "I252",
+  # Boolean ... in function definition
+  "FBT001", "FBT002",
+  # Module level import not at top of file
+  "E402",
+  # A001/A002/A003 .. is shadowing a python builtin
+  "A001", "A002", "A003",
+  # Possible hardcoded password
+  "S105", "S106",
+  # Q000 Single quotes found but double quotes preferred
+  "Q000",
+  # N806 Variable `B` in function should be lowercase
+  "N806",
+  # T201 `print` found
+  "T201",
+  # N802 Function name `CreateWellKnownSid` should be lowercase
+  "N802", "N803",
+  # C408 Unnecessary `dict` call (rewrite as a literal)
+  "C408",
+  # N801 Class name `directional_link` should use CapWords convention
+  "N801",
 ]
-per-file-ignores = [
-    # B011: Do not call assert False since python -O removes these calls
-    # F841 local variable 'foo' is assigned to but never used
-    "traitlets/tests/*: B011", "F841",
-    # F401 'foo' imported but unused
-    # F403 'from foo import *' used; unable to detect undefined names
-    "traitlets/__init__.py: F401", "F403",
-    "traitlets/*/__init__.py: F401", "F403",
+unfixable = [
+  # Don't touch print statements
+  "T201",
+  # Don't touch noqa lines
+  "RUF100",
 ]
+
+[tool.ruff.per-file-ignores]
+# B011 Do not call assert False since python -O removes these calls
+# F841 local variable 'foo' is assigned to but never used
+# C408 Unnecessary `dict` call
+# E402 Module level import not at top of file
+# T201 `print` found
+# B007 Loop control variable `i` not used within the loop body.
+# N802 Function name `assertIn` should be lowercase
+# F841 Local variable `t` is assigned to but never used
+"traitlets/tests/*" = ["B011", "F841", "C408", "E402", "T201", "B007", "N802", "F841"]
+# F401 `_version.__version__` imported but unused
+# F403 `from .traitlets import *` used; unable to detect undefined names
+"traitlets/*__init__.py" = ["F401", "F403"]

traitlets/config/application.py

@@ -366,7 +366,9 @@ def _log_default(self):
     # flags are loaded from this dict by '--key' flags
     # this must be a dict of two-tuples, the first element being the Config/dict
     # and the second being the help string for the flag
-    flags: t.Dict[t.Union[str, t.Tuple[str, ...]], t.Tuple[t.Union[t.Dict, Config], str]] = {
+    flags: t.Dict[
+        t.Union[str, t.Tuple[str, ...]], t.Tuple[t.Union[t.Dict[str, t.Any], Config], str]
+    ] = {
         "debug": (
             {
                 "Application": {
@@ -537,12 +539,13 @@ def emit_alias_help(self):
                 fhelp = cls.class_get_trait_help(trait, helptext=fhelp).splitlines()
 
                 if not isinstance(alias, tuple):
-                    alias = (alias,)  # type:ignore[assignment]
+                    alias = (alias,)
                 alias = sorted(alias, key=len)  # type:ignore[assignment]
                 alias = ", ".join(("--%s" if len(m) > 1 else "-%s") % m for m in alias)
 
                 # reformat first line
-                fhelp[0] = fhelp[0].replace("--" + longname, alias)
+                assert fhelp is not None
+                fhelp[0] = fhelp[0].replace("--" + longname, alias)  # type:ignore
                 yield from fhelp
                 yield indent("Equivalent to: [--%s]" % longname)
             except Exception as ex:
@@ -561,7 +564,7 @@ def emit_flag_help(self):
         for flags, (cfg, fhelp) in self.flags.items():
             try:
                 if not isinstance(flags, tuple):
-                    flags = (flags,)  # type:ignore[assignment]
+                    flags = (flags,)
                 flags = sorted(flags, key=len)  # type:ignore[assignment]
                 flags = ", ".join(("--%s" if len(m) > 1 else "-%s") % m for m in flags)
                 yield flags
@@ -748,7 +751,7 @@ def flatten_flags(self):
         for alias, longname in self.aliases.items():
             if isinstance(longname, tuple):
                 longname, _ = longname
-            cls, trait = longname.split(".", 1)
+            cls, trait = longname.split(".", 1)  # type:ignore
             children = mro_tree[cls]  # type:ignore[index]
             if len(children) == 1:
                 # exactly one descendent, promote alias
@@ -763,7 +766,7 @@ def flatten_flags(self):
         flags = {}
         for key, (flagdict, help) in self.flags.items():
             newflag: t.Dict[t.Any, t.Any] = {}
-            for cls, subdict in flagdict.items():
+            for cls, subdict in flagdict.items():  # type:ignore
                 children = mro_tree[cls]  # type:ignore[index]
                 # exactly one descendent, promote flag section
                 if len(children) == 1:
@@ -775,7 +778,7 @@ def flatten_flags(self):
                     newflag[cls] = subdict
 
             if not isinstance(key, tuple):
-                key = (key,)  # type:ignore[assignment]
+                key = (key,)
             for k in key:
                 flags[k] = (newflag, help)
         return flags, aliases
@@ -952,7 +955,7 @@ def generate_config_file(self, classes=None):
         """generate default config file from Configurables"""
         lines = ["# Configuration file for %s." % self.name]
         lines.append("")
-        lines.append("c = get_config()  # noqa")
+        lines.append("c = get_config()  #" + "noqa")
         lines.append("")
         classes = self.classes if classes is None else classes
         config_classes = list(self._classes_with_config_traits(classes))