codespell_lib/_codespell.py: read additional args from file with with…

README.rst

@@ -229,6 +229,13 @@ instead of these invalid entries:
 
 .. _tomli: https://pypi.org/project/tomli/
 
+Reading arguments from file
+---------------------------
+
+Additional arguments can be read from a file with ``@PATH``. Arguments are
+extracted using ``shlex.split()``.
+
+
 pre-commit hook
 ---------------
 

codespell_lib/_codespell.py

@@ -23,6 +23,7 @@
 import itertools
 import os
 import re
+import shlex
 import sys
 import textwrap
 from collections.abc import Iterable, Sequence
@@ -388,7 +389,18 @@ def _supports_ansi_colors() -> bool:
 def parse_options(
     args: Sequence[str],
 ) -> tuple[argparse.Namespace, argparse.ArgumentParser, list[str]]:
-    parser = argparse.ArgumentParser(formatter_class=NewlineHelpFormatter)
+    # Split lines read from `@PATH` using shlex.split(), otherwise default
+    # behaviour is to have one arg per line. See:
+    # https://docs.python.org/3/library/argparse.html#argparse.ArgumentParser.convert_arg_line_to_args
+    class ArgumentParser(argparse.ArgumentParser):
+        def convert_arg_line_to_args(self, arg_line: str) -> list[str]:
+            return shlex.split(arg_line)
+
+    parser = ArgumentParser(
+        formatter_class=NewlineHelpFormatter,
+        fromfile_prefix_chars="@",
+        epilog="Use @<path> to read additional arguments from file <path>.",
+    )
 
     parser.set_defaults(colors=_supports_ansi_colors())
     parser.add_argument("--version", action="version", version=VERSION)