Use ruff for linting (#404)

Also fixes a few items that were marked as issues by ruff.

7 files changed, 35 insertions, 14 deletions

diff --git a/gitlint-core/gitlint/cli.py b/gitlint-core/gitlint/cli.py
index 387072e..d1ed456 100644
--- a/gitlint-core/gitlint/cli.py
+++ b/gitlint-core/gitlint/cli.py
@@ -172,11 +172,9 @@ def build_git_context(lint_config, msg_filename, commit_hash, refspec):
     from_commit_msg = GitContext.from_commit_msg
     if lint_config.staged:
         LOG.debug("Fetching additional meta-data from staged commit")
-        from_commit_msg = (
-            lambda message: GitContext.from_staged_commit(  # pylint: disable=unnecessary-lambda-assignment
-                message, lint_config.target
-            )
-        )
+
+        def from_commit_msg(message):
+            return GitContext.from_staged_commit(message, lint_config.target)
 
     # Order of precedence:
     # 1. Any data specified via --msg-filename
diff --git a/gitlint-core/gitlint/tests/cli/test_cli.py b/gitlint-core/gitlint/tests/cli/test_cli.py
index 45093dd..f0177c4 100644
--- a/gitlint-core/gitlint/tests/cli/test_cli.py
+++ b/gitlint-core/gitlint/tests/cli/test_cli.py
@@ -1,4 +1,3 @@
-import io
 import os
 import sys
 import platform
diff --git a/gitlint-core/gitlint/tests/cli/test_cli_hooks.py b/gitlint-core/gitlint/tests/cli/test_cli_hooks.py
index 6564a64..cfdb704 100644
--- a/gitlint-core/gitlint/tests/cli/test_cli_hooks.py
+++ b/gitlint-core/gitlint/tests/cli/test_cli_hooks.py
@@ -1,4 +1,3 @@
-import io
 from io import StringIO
 import os
 
diff --git a/gitlint-core/gitlint/tests/git/test_git_commit.py b/gitlint-core/gitlint/tests/git/test_git_commit.py
index b27deaf..ee76a96 100644
--- a/gitlint-core/gitlint/tests/git/test_git_commit.py
+++ b/gitlint-core/gitlint/tests/git/test_git_commit.py
@@ -10,7 +10,6 @@ from unittest.mock import patch, call
 
 from gitlint.tests.base import BaseTestCase
 from gitlint.git import (
-    GitChangedFileStats,
     GitContext,
     GitCommit,
     GitContextError,
diff --git a/pyproject.toml b/pyproject.toml
index b45cbcf..4a5bed2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -88,6 +88,7 @@ dependencies = [
     "pytest-cov==4.0.0",
     "python-coveralls==2.9.3",
     "pylint==2.15.3",
+    "ruff==0.0.211",
     "radon==5.1.0",
     "pdbr==0.7.5; sys_platform != \"win32\""
 ]
@@ -99,12 +100,17 @@ unit-tests = [
 u = "unit-tests"
 unit-tests-no-cov = "pytest -rw -s {args:gitlint-core}"
 format = "black --check --diff ."
-lint = "pylint gitlint-core/gitlint qa"
+plint = "pylint gitlint-core/gitlint qa"
+lint = "ruff gitlint-core/gitlint qa"
+autofix = [
+    "ruff --fix gitlint-core/gitlint qa",
+    "black .",
+]
 
 all = [
     "unit-tests",
     "format",
-    "lint"
+    "lint",
 ]
 stats = [
     "./tools/stats.sh"
@@ -154,6 +160,26 @@ line-length = 120
 # extend-exclude: keep excluding files from .gitignore in addition to the ones specified
 extend-exclude =  "gitlint-core/gitlint/tests/samples/user_rules/import_exception/invalid_python.py"
 
+[tool.ruff]
+target-version = "py37"
+extend-exclude =  ["gitlint-core/gitlint/tests/samples/user_rules/import_exception/invalid_python.py"]
+
+ignore = [
+    "E501", # Never enforce `E501` (line length violations) - taken care of by black
+]
+
+select = [
+    "E",    # Pycodestyle
+    "F",    # PyFlakes
+    "T20",  # no print statements
+    "UP",   # pyupgrade
+    "PLC",  # pylint 
+    "PLE",  # pylint
+    "PLR",  # pylint
+    "PLW",  # pylint
+    "RUF",  # ruff specific
+]
+
 [tool.coverage.run]
 branch = true # measure branch coverage in addition to statement coverage
 
diff --git a/qa/samples/user_rules/extra/extra_rules.py b/qa/samples/user_rules/extra/extra_rules.py
index cad531b..fa05879 100644
--- a/qa/samples/user_rules/extra/extra_rules.py
+++ b/qa/samples/user_rules/extra/extra_rules.py
@@ -64,9 +64,9 @@ class ConfigurableCommitRule(CommitRule):
 
     def validate(self, _):
         violations = [
-            RuleViolation(self.id, f"int-öption: {self.options[u'int-öption'].value}", line_nr=1),
-            RuleViolation(self.id, f"str-öption: {self.options[u'str-öption'].value}", line_nr=1),
-            RuleViolation(self.id, f"list-öption: {self.options[u'list-öption'].value}", line_nr=1),
+            RuleViolation(self.id, f"int-öption: {self.options['int-öption'].value}", line_nr=1),
+            RuleViolation(self.id, f"str-öption: {self.options['str-öption'].value}", line_nr=1),
+            RuleViolation(self.id, f"list-öption: {self.options['list-öption'].value}", line_nr=1),
         ]
 
         return violations
diff --git a/qa/shell.py b/qa/shell.py
index 7cddf3b..ef94727 100644
--- a/qa/shell.py
+++ b/qa/shell.py
@@ -49,7 +49,7 @@ else:
 
         def __getattr__(self, p):  # pylint: disable=invalid-name
             # https://github.com/amoffat/sh/blob/e0ed8e244e9d973ef4e0749b2b3c2695e7b5255b/sh.py#L952=
-            _unicode_methods = set(dir(str()))
+            _unicode_methods = set(dir(str()))  # noqa
             if p in _unicode_methods:
                 return getattr(str(self), p)