Add support for ruff

Fix #17
See https://docs.astral.sh/ruff

vcs-diff-lint

@@ -25,6 +25,9 @@ CSDIFF_PYLINT = os.path.realpath(os.path.join(os.path.dirname(__file__),
 CSDIFF_MYPY = os.path.realpath(os.path.join(os.path.dirname(__file__),
                                             'vcs-diff-lint-csdiff-mypy'))
 
+CSDIFF_RUFF = os.path.realpath(
+    os.path.join(os.path.dirname(__file__), 'vcs-diff-lint-csdiff-ruff'))
+
 
 def _run_csdiff(old, new, msg):
     popen_diff = Popen(['csdiff', '-c', old, new],
@@ -170,6 +173,23 @@ class MypyLinter(_Linter):
         return cmd, {}
 
 
+class RuffLinter(_Linter):
+    """
+    Generate Ruff error output compatible with 'csdiff'.
+    """
+    linter_tags = [
+        "ruff",
+        "python",
+    ]
+
+    def is_compatible(self, file):
+        return file.type == 'python'
+
+    def command(self, projectdir, filenames):
+        cmd = [CSDIFF_RUFF] + filenames
+        return cmd, {}
+
+
 def get_rename_map(options, subdir):
     """
     Using the os.getcwd() and 'git diff --namestatus', generate list of
@@ -213,7 +233,7 @@ class _Worker:  # pylint: disable=too-few-public-methods
     projectsubdir = None
     workdir = None
     checkout = None
-    linters = [PylintLinter, MypyLinter]
+    linters = [PylintLinter, MypyLinter, RuffLinter]
 
     def __init__(self, options):
         self.options = options

vcs-diff-lint-csdiff-ruff

@@ -0,0 +1,64 @@
+#! /usr/bin/python3
+
+"""
+The csdiff tool doesn't support the Ruff's JSON output yet.  So this just a
+trivial wrapper which reads Ruff's report and transforms it to JSON which is
+supported by csdiff.
+
+The script accepts the same parameters as `ruff check` itself.
+"""
+
+import os
+import sys
+import json
+from subprocess import Popen, PIPE
+
+
+def ruff_check():
+    """
+    Run `ruff check` and return a dict with its results
+    """
+    cmd = ["ruff", "check", "--output-format=json"] + sys.argv[1:]
+    proc = Popen(cmd, stdout=PIPE)
+    out, _err = proc.communicate(timeout=60)
+    return json.loads(out)
+
+
+def ruff_code_to_name(code):
+    """
+    Convert noqa code e.g. F401 to its human-readable name, e.g. unused-import
+    """
+    # This implementation will likely kill all ruff performance benefits
+    cmd = ["ruff", "rule", code, "--output-format=json"]
+    proc = Popen(cmd, stdout=PIPE)
+    out, _err = proc.communicate(timeout=60)
+    data = json.loads(out)
+    return data["name"]
+
+
+def main():
+    """
+    The main fuction
+    """
+    defects = ruff_check()
+    for defect in defects:
+        path = os.path.relpath(defect["filename"])
+        column = defect["location"]["column"] or ""
+        colsep = ":" if column else ""
+        event = "{0}[{1}]".format(
+            defect["code"], ruff_code_to_name(defect["code"]))
+
+        print("Error: RUFF_WARNING:")
+        print("{file}:{line}{colsep}{column}: {event}: {msg}".format(
+            file=path,
+            line=defect["location"]["row"],
+            colsep=colsep,
+            column=column,
+            event=event,
+            msg=defect["message"],
+        ))
+        print()
+
+
+if __name__ == "__main__":
+    sys.exit(main())