add in-place CLI formatting with side-by-side diff option and ignore support

Author: rongxin-liu

style50/__main__.py

@@ -34,21 +34,37 @@ def main():
     parser.add_argument("-o", "--output", action="store", default="character",
                         choices=["character", "split", "unified", "score", "json", "html", "format"], metavar="MODE",
                         help="output mode, which can be character (default), split, unified, score, json, html, or format")
+    parser.add_argument("-y", "--side-by-side", action="store_true",
+                        help="show side-by-side diff (equivalent to -o split)")
+    parser.add_argument("-i", "--in-place", action="store_true",
+                        help="rewrite files in place with style50 formatting")
     parser.add_argument("-v", "--verbose", action="store_true",
                         help="print full tracebacks of errors")
     parser.add_argument("-V", "--version", action="version",
                         version="%(prog)s {}".format(__version__))
     parser.add_argument("-E", "--extensions", action="version",
                         version=json.dumps(list(Style50.extension_map.keys())),
                         help="print supported file extensions (as JSON list) and exit")
-    parser.add_argument("-i", "--ignore", action="append", metavar="PATTERN",
+    parser.add_argument("--ignore", action="append", metavar="PATTERN",
                         help="paths/patterns to be ignored")
     parser.add_argument("--clang-format-style", metavar="STYLE",
                         help="clang-format style string or file:// URI (overrides default CS50 config)")
 
     args = parser.parse_args()
     ignore = args.ignore or filter(None, os.getenv("STYLE50_IGNORE", "").split(","))
 
+    if args.in_place and args.side_by_side:
+        sys.exit("--in-place cannot be combined with --side-by-side")
+
+    if args.side_by_side:
+        args.output = "split"
+
+    if args.in_place:
+        if args.output != "character":
+            sys.exit("--in-place cannot be combined with --output")
+        Style50("format", clang_format_style=args.clang_format_style).format_files_in_place(args.file, ignore=ignore)
+        return
+
     if args.output == "format":
         if len(args.file) != 1:
             sys.exit("format mode requires exactly one file")

style50/_api.py

@@ -60,6 +60,32 @@ def format_file(self, path):
         results = self._check(path)
         return results.styled
 
+    def format_files_in_place(self, paths, ignore=[]):
+        """Format files and rewrite each path in place."""
+        try:
+            # Translate each ignore pattern into a regex and compile it
+            ignore = [re.compile(fnmatch.translate(i)) for i in ignore]
+        except re.error:
+            raise Error("failed to parse ignore pattern")
+
+        files = list(filter(lambda p: not any(reg.match(p) for reg in ignore),
+                            itertools.chain.from_iterable([path] if not os.path.isdir(path)
+                                                          else (os.path.join(root, file)
+                                                                for root, _, files in os.walk(path)
+                                                                for file in files)
+                                                          for path in paths)))
+
+        for path in files:
+            try:
+                results = self._check(path)
+            except Error as e:
+                termcolor.cprint(f"{path}: {e.msg}", "red", file=sys.stderr)
+                continue
+
+            if results.original != results.styled:
+                with open(path, "w") as file:
+                    file.write(results.styled)
+
     def run(self, *args, **kwargs):
         """Wraps Style50.check and renders the results using the renderer determined by self.output"""
         if self.output == "format":

tests/test_cli.py

@@ -46,3 +46,69 @@ def test_clang_format_style_arg_is_accepted_in_format_mode(tmp_path):
     assert proc.returncode == 0
     assert proc.stdout.strip() != ""
 
+
+def test_in_place_rewrites_file(tmp_path):
+    f = tmp_path / "t.py"
+    original = "x=1\nprint(  x)\n"
+    f.write_text(original, encoding="utf-8")
+
+    proc = run_style50(["-i", str(f)])
+    assert proc.returncode == 0
+
+    updated = f.read_text(encoding="utf-8")
+    assert updated != original
+    assert "print(x)" in updated
+
+
+def test_in_place_multiple_files(tmp_path):
+    f1 = tmp_path / "a.py"
+    f2 = tmp_path / "b.py"
+    f1.write_text("x=1\nprint(  x)\n", encoding="utf-8")
+    f2.write_text("y=2\nprint(  y)\n", encoding="utf-8")
+
+    proc = run_style50(["-i", str(f1), str(f2)])
+    assert proc.returncode == 0
+    assert "print(x)" in f1.read_text(encoding="utf-8")
+    assert "print(y)" in f2.read_text(encoding="utf-8")
+
+
+def test_in_place_skips_already_styled(tmp_path):
+    f = tmp_path / "t.py"
+    original = "x = 1\nprint(x)\n"
+    f.write_text(original, encoding="utf-8")
+
+    proc = run_style50(["-i", str(f)])
+    assert proc.returncode == 0
+    assert f.read_text(encoding="utf-8") == original
+
+
+def test_side_by_side_flag(tmp_path):
+    f = tmp_path / "t.py"
+    f.write_text("x=1\nprint(  x)\n", encoding="utf-8")
+
+    proc = run_style50(["-y", str(f)])
+    assert proc.returncode == 0
+    assert proc.stdout.strip() != ""
+
+
+def test_in_place_and_side_by_side_conflict(tmp_path):
+    f = tmp_path / "t.py"
+    f.write_text("x=1\nprint(  x)\n", encoding="utf-8")
+
+    proc = run_style50(["-i", "-y", str(f)])
+    assert proc.returncode != 0
+    assert "--in-place cannot be combined with --side-by-side" in (proc.stdout + proc.stderr)
+
+
+def test_in_place_respects_ignore(tmp_path):
+    keep = tmp_path / "keep.py"
+    skip = tmp_path / "skip.py"
+    keep.write_text("x=1\nprint(  x)\n", encoding="utf-8")
+    skip.write_text("y=1\nprint(  y)\n", encoding="utf-8")
+
+    proc = run_style50(["-i", "--ignore", "*skip.py", str(keep), str(skip)])
+    assert proc.returncode == 0
+
+    assert "print(x)" in keep.read_text(encoding="utf-8")
+    assert "print(  y)" in skip.read_text(encoding="utf-8")
+