Migrate from black + pyupgrade to ruff

- Replace black and pyupgrade with ruff-check and ruff-format hooks
- Configure ruff with isort (I), bugbear (B), pyupgrade (UP),
  and pytest-style (PT) rules
- Set force-single-line imports for isort
- Auto-fix imports and code style with ruff

Ruff automatically:
- Sorted and organized imports (isort)
- Upgraded to modern Python syntax (pyupgrade)
- Applied bugbear fixes
- Fixed pytest style issues (renamed shadowing variables)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: RonnyPfannschmidt

.pre-commit-config.yaml

@@ -1,24 +1,21 @@
 repos:
--   repo: https://github.com/asottile/pyupgrade
-    rev: v3.21.0
-    hooks:
-    -   id: pyupgrade
-        args: [--py38-plus]
 - repo: https://github.com/tox-dev/pyproject-fmt
   rev: "v2.11.0"
   hooks:
     - id: pyproject-fmt
 
-- repo: https://github.com/psf/black
-  rev: 25.9.0
+- repo: https://github.com/astral-sh/ruff-pre-commit
+  rev: v0.14.1
   hooks:
-      - id: black
-        language_version: python3
--   repo: https://github.com/pre-commit/mirrors-mypy
-    rev: 'v1.18.2' 
-    hooks:
-    -   id: mypy
-        args: []
-        additional_dependencies:
-          - "pytest==7.2.0"
-          - "tomli"
+    - id: ruff-check
+      args: [--fix]
+    - id: ruff-format
+
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: 'v1.18.2'
+  hooks:
+    - id: mypy
+      args: []
+      additional_dependencies:
+        - "pytest==7.2.0"
+        - "tomli"

pyproject.toml

@@ -46,6 +46,17 @@ iniconfig = [ "py.typed" ]
 [tool.setuptools_scm]
 write_to = "src/iniconfig/_version.py"
 
+[tool.ruff]
+
+lint.extend-select = [
+  "B",  # flake8-bugbear
+  "I",  # isort
+  "PT", # flake8-pytest-style
+  "UP", # pyupgrade
+]
+lint.isort.force-single-line = true
+lint.isort.known-first-party = [ "iniconfig" ]
+
 [tool.pytest.ini_options]
 testpaths = "testing"
 

src/iniconfig/__init__.py

@@ -3,25 +3,24 @@
 """
 
 from __future__ import annotations
-from typing import (
-    Callable,
-    Iterator,
-    Mapping,
-    TypeVar,
-    TYPE_CHECKING,
-    overload,
-)
 
 import os
+from collections.abc import Callable
+from collections.abc import Iterator
+from collections.abc import Mapping
+from typing import TYPE_CHECKING
+from typing import TypeVar
+from typing import overload
 
 if TYPE_CHECKING:
     from typing import Final
 
 __all__ = ["IniConfig", "ParseError", "COMMENTCHARS", "iscommentline"]
 
-from .exceptions import ParseError
 from . import _parse
-from ._parse import COMMENTCHARS, iscommentline
+from ._parse import COMMENTCHARS
+from ._parse import iscommentline
+from .exceptions import ParseError
 
 _D = TypeVar("_D")
 _T = TypeVar("_T")

src/iniconfig/_parse.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
-from .exceptions import ParseError
 
 from typing import NamedTuple
 
+from .exceptions import ParseError
 
 COMMENTCHARS = "#;"
 
@@ -70,7 +70,7 @@ def _parseline(path: str, line: str, lineno: int) -> tuple[str | None, str | Non
             try:
                 name, value = line.split(":", 1)
             except ValueError:
-                raise ParseError(path, lineno, "unexpected line: %r" % line)
+                raise ParseError(path, lineno, f"unexpected line: {line!r}") from None
         return name.strip(), value.strip()
     # continuation
     else:

src/iniconfig/exceptions.py

@@ -1,4 +1,5 @@
 from __future__ import annotations
+
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:

testing/test_iniconfig.py

@@ -1,11 +1,15 @@
 from __future__ import annotations
-import pytest
-from iniconfig import IniConfig, ParseError, __all__ as ALL
-from iniconfig._parse import _ParsedLine as PL
-from iniconfig import iscommentline
-from textwrap import dedent
+
 from pathlib import Path
+from textwrap import dedent
 
+import pytest
+
+from iniconfig import IniConfig
+from iniconfig import ParseError
+from iniconfig import __all__ as ALL
+from iniconfig import iscommentline
+from iniconfig._parse import _ParsedLine as PL
 
 check_tokens: dict[str, tuple[str, list[PL]]] = {
     "section": ("[section]", [PL(0, "section", None, None)]),
@@ -44,7 +48,6 @@
 
 @pytest.fixture(params=sorted(check_tokens))
 def input_expected(request: pytest.FixtureRequest) -> tuple[str, list[PL]]:
-
     return check_tokens[request.param]
 
 
@@ -214,12 +217,12 @@ def test_config_iter() -> None:
     """
         ),
     )
-    l = list(config)
-    assert len(l) == 2
-    assert l[0].name == "section1"
-    assert l[0]["value"] == "1"
-    assert l[1].name == "section2"
-    assert l[1]["value"] == "2"
+    sections = list(config)
+    assert len(sections) == 2
+    assert sections[0].name == "section1"
+    assert sections[0]["value"] == "1"
+    assert sections[1].name == "section2"
+    assert sections[1]["value"] == "2"
 
 
 def test_config_contains() -> None:
@@ -251,8 +254,8 @@ def test_iter_file_order() -> None:
 b = 2
 """,
     )
-    l = list(config)
-    secnames = [x.name for x in l]
+    sections_list = list(config)
+    secnames = [x.name for x in sections_list]
     assert secnames == ["section2", "section"]
     assert list(config["section2"]) == ["value", "value2"]
     assert list(config["section"]) == ["a", "b"]