Meta+CI: Enforce python linting with ruff

We could use flake8 for linting, but ruff is compatible with black
formatting out-of-the-box. It also seems to catch more than flake8,
such as unnecessary f-strings.

.github/workflows/lint-code.yml

@@ -15,7 +15,7 @@ jobs:
         run: |
           set -e
 
-          brew install black curl llvm@20 ninja optipng shellcheck swift-format unzip
+          brew install curl llvm@20 ninja optipng ruff shellcheck swift-format unzip
 
           # Note: gn isn't available in homebrew :(
           # Corresponds to https://gn.googlesource.com/gn/+/225e90c5025bf74f41dbee60d9cde4512c846fe7

Meta/lint-python.sh

@@ -5,11 +5,11 @@ set -e
 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "${script_path}/.." || exit 1
 
-check_argument="--check"
+overwrite=0
 
 if [ "$#" -gt "0" ]; then
     if  [ "--overwrite-inplace" = "$1" ] ; then
-        check_argument=""
+        overwrite=1
         shift
     fi
 fi
@@ -31,12 +31,18 @@ else
 fi
 
 if (( ${#files[@]} )); then
-    if ! command -v black >/dev/null 2>&1 ; then
-        echo "black is not available, but python files need linting! Either skip this script, or install black."
+    if ! command -v ruff >/dev/null 2>&1 ; then
+        echo "Please install ruff: pip3 install ruff"
         exit 1
     fi
 
-    black ${check_argument} "${files[@]}"
+    if [[ ${overwrite} -eq 0 ]] ; then
+        ruff check "${files[@]}"
+        ruff format --check "${files[@]}"
+    else
+        ruff check --fix "${files[@]}"
+        ruff format "${files[@]}"
+    fi
 else
     echo "No py files to check."
 fi

pyproject.toml

@@ -1,2 +1,14 @@
 [tool.black]
 line-length = 120
+
+[tool.ruff]
+line-length = 120
+
+[tool.ruff.lint]
+# On top of the defaults (`E4`, E7`, `E9`, and `F`), enable flake8-bugbear (`B`) and isort (`i`).
+# https://docs.astral.sh/ruff/rules/
+select = ["E4", "E7", "E9", "F", "B", "I"]
+
+[tool.ruff.lint.isort]
+force-single-line = true
+lines-between-types = 1