ruff linter

INSTALL.md

@@ -178,6 +178,9 @@ sudo apt install git
 sudo apt install tesseract-ocr
 ```
 
+Developers might want to use `ruff` as a pre-commit linter. Install it with `pip install ruff` then use `ruff check` to analyze code.
+We have supplied a ruff.toml config file in the root of the project.
+
 <div id="setup-pyfedi"></div>
 
 ## Setup PyFedi

ruff.toml

@@ -0,0 +1,63 @@
+# Exclude a variety of commonly ignored directories.
+exclude = [
+    ".bzr",
+    ".direnv",
+    ".eggs",
+    ".git",
+    ".git-rewrite",
+    ".hg",
+    ".ipynb_checkpoints",
+    ".mypy_cache",
+    ".nox",
+    ".pants.d",
+    ".pyenv",
+    ".pytest_cache",
+    ".pytype",
+    ".ruff_cache",
+    ".svn",
+    ".tox",
+    ".venv",
+    ".vscode",
+    "__pypackages__",
+    "_build",
+    "buck-out",
+    "build",
+    "dist",
+    "node_modules",
+    "site-packages",
+    "venv",
+    "offline_utilities",
+    "static"
+]
+
+# Same as Black.
+line-length = 88
+indent-width = 4
+
+# Assume Python 3.9
+target-version = "py39"
+
+[lint]
+# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
+select = ["E4", "E7", "E9", "F"]
+ignore = ["E402", "F401"]
+
+# Allow fix for all enabled rules (when `--fix`) is provided.
+fixable = ["ALL"]
+unfixable = []
+
+# Allow unused variables when underscore-prefixed.
+dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
+
+[format]
+# Like Black, use double quotes for strings.
+quote-style = "double"
+
+# Like Black, indent with spaces, rather than tabs.
+indent-style = "space"
+
+# Like Black, respect magic trailing commas.
+skip-magic-trailing-comma = false
+
+# Like Black, automatically detect the appropriate line ending.
+line-ending = "auto"