1 files changed, 187 insertions, 0 deletions
diff --git a/tools/lint/python/ruff.py b/tools/lint/python/ruff.py
new file mode 100644
index 0000000000..d8096199f3
--- /dev/null
+++ b/tools/lint/python/ruff.py
@@ -0,0 +1,187 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import json
+import os
+import platform
+import re
+import signal
+import subprocess
+import sys
+from pathlib import Path
+
+import mozfile
+from mozlint import result
+from mozprocess.processhandler import ProcessHandler
+
+here = os.path.abspath(os.path.dirname(__file__))
+RUFF_REQUIREMENTS_PATH = os.path.join(here, "ruff_requirements.txt")
+
+RUFF_NOT_FOUND = """
+Could not find ruff! Install ruff and try again.
+
+    $ pip install -U --require-hashes -r {}
+""".strip().format(
+    RUFF_REQUIREMENTS_PATH
+)
+
+
+RUFF_INSTALL_ERROR = """
+Unable to install correct version of ruff!
+Try to install it manually with:
+    $ pip install -U --require-hashes -r {}
+""".strip().format(
+    RUFF_REQUIREMENTS_PATH
+)
+
+
+def default_bindir():
+    # We use sys.prefix to find executables as that gets modified with
+    # virtualenv's activate_this.py, whereas sys.executable doesn't.
+    if platform.system() == "Windows":
+        return os.path.join(sys.prefix, "Scripts")
+    else:
+        return os.path.join(sys.prefix, "bin")
+
+
+def get_ruff_version(binary):
+    """
+    Returns found binary's version
+    """
+    try:
+        output = subprocess.check_output(
+            [binary, "--version"],
+            stderr=subprocess.STDOUT,
+            text=True,
+        )
+    except subprocess.CalledProcessError as e:
+        output = e.output
+
+    matches = re.match(r"ruff ([0-9\.]+)", output)
+    if matches:
+        return matches[1]
+    print("Error: Could not parse the version '{}'".format(output))
+
+
+def setup(root, log, **lintargs):
+    virtualenv_bin_path = lintargs.get("virtualenv_bin_path")
+    binary = mozfile.which("ruff", path=(virtualenv_bin_path, default_bindir()))
+
+    if binary and os.path.isfile(binary):
+        log.debug(f"Looking for ruff at {binary}")
+        version = get_ruff_version(binary)
+        versions = [
+            line.split()[0].strip()
+            for line in open(RUFF_REQUIREMENTS_PATH).readlines()
+            if line.startswith("ruff==")
+        ]
+        if [f"ruff=={version}"] == versions:
+            log.debug("ruff is present with expected version {}".format(version))
+            return 0
+        else:
+            log.debug("ruff is present but unexpected version {}".format(version))
+
+    virtualenv_manager = lintargs["virtualenv_manager"]
+    try:
+        virtualenv_manager.install_pip_requirements(RUFF_REQUIREMENTS_PATH, quiet=True)
+    except subprocess.CalledProcessError:
+        print(RUFF_INSTALL_ERROR)
+        return 1
+
+
+class RuffProcess(ProcessHandler):
+    def __init__(self, config, *args, **kwargs):
+        self.config = config
+        self.stderr = []
+        kwargs["stream"] = False
+        kwargs["universal_newlines"] = True
+        ProcessHandler.__init__(self, *args, **kwargs)
+
+    def run(self, *args, **kwargs):
+        orig = signal.signal(signal.SIGINT, signal.SIG_IGN)
+        ProcessHandler.run(self, *args, **kwargs)
+        signal.signal(signal.SIGINT, orig)
+
+
+def run_process(config, cmd, **kwargs):
+    proc = RuffProcess(config, cmd, **kwargs)
+    proc.run()
+    try:
+        proc.wait()
+    except KeyboardInterrupt:
+        proc.kill()
+
+    return "\n".join(proc.output)
+
+
+def lint(paths, config, log, **lintargs):
+    fixed = 0
+    results = []
+
+    if not paths:
+        return {"results": results, "fixed": fixed}
+
+    # Currently ruff only lints non `.py` files if they are explicitly passed
+    # in. So we need to find any non-py files manually. This can be removed
+    # after https://github.com/charliermarsh/ruff/issues/3410 is fixed.
+    exts = [e for e in config["extensions"] if e != "py"]
+    non_py_files = []
+    for path in paths:
+        p = Path(path)
+        if not p.is_dir():
+            continue
+        for ext in exts:
+            non_py_files.extend([str(f) for f in p.glob(f"**/*.{ext}")])
+
+    args = ["ruff", "check", "--force-exclude"] + paths + non_py_files
+
+    if config["exclude"]:
+        args.append(f"--extend-exclude={','.join(config['exclude'])}")
+
+    process_kwargs = {"processStderrLine": lambda line: log.debug(line)}
+
+    warning_rules = set(config.get("warning-rules", []))
+    if lintargs.get("fix"):
+        # Do a first pass with --fix-only as the json format doesn't return the
+        # number of fixed issues.
+        fix_args = args + ["--fix-only"]
+
+        # Don't fix warnings to limit unrelated changes sneaking into patches.
+        fix_args.append(f"--extend-ignore={','.join(warning_rules)}")
+        output = run_process(config, fix_args, **process_kwargs)
+        matches = re.match(r"Fixed (\d+) errors?.", output)
+        if matches:
+            fixed = int(matches[1])
+
+    log.debug(f"Running with args: {args}")
+
+    output = run_process(config, args + ["--format=json"], **process_kwargs)
+    if not output:
+        return []
+
+    try:
+        issues = json.loads(output)
+    except json.JSONDecodeError:
+        log.error(f"could not parse output: {output}")
+        return []
+
+    for issue in issues:
+        res = {
+            "path": issue["filename"],
+            "lineno": issue["location"]["row"],
+            "column": issue["location"]["column"],
+            "lineoffset": issue["end_location"]["row"] - issue["location"]["row"],
+            "message": issue["message"],
+            "rule": issue["code"],
+            "level": "error",
+        }
+        if any(issue["code"].startswith(w) for w in warning_rules):
+            res["level"] = "warning"
+
+        if issue["fix"]:
+            res["hint"] = issue["fix"]["message"]
+
+        results.append(result.from_config(config, **res))
+
+    return {"results": results, "fixed": fixed}