fix: exposing func arg in CLI under a different name (fixes #224)

CHANGELOG.rst

@@ -6,8 +6,10 @@ Version 0.31.3
 
 Bugs fixed:
 
-- fix type annotation of `errors` in `wrap_errors` (PR #229 by @laazy)
-- test failures under Python 3.13 (issue #228 by @mgorny).
+- wrong type annotation of `errors` in `wrap_errors` (PR #229 by @laazy)
+- tests were failing under Python 3.13 (issue #228 by @mgorny)
+- regression: can't set argument name with `dest` via decorator
+  (issue #224 by @mathieulongtin)
 
 Version 0.31.2 (2024-01-24)
 ---------------------------

src/argh/decorators.py

@@ -140,7 +140,11 @@ def wrapper(func: Callable) -> Callable:
         if not args:
             raise CliArgToFuncArgGuessingError("at least one CLI arg must be defined")
 
-        func_arg_name = naive_guess_func_arg_name(args)
+        if "dest" in kwargs:
+            func_arg_name = kwargs.pop("dest")
+        else:
+            func_arg_name = naive_guess_func_arg_name(args)
+
         cli_arg_names = [name.replace("_", "-") for name in args]
         completer = kwargs.pop("completer", None)
         spec = ParserAddArgumentSpec.make_from_kwargs(

tests/test_regressions.py

@@ -242,3 +242,22 @@ def func(*, paths: Optional[List[str]] = ["one", "two"]):
     assert run(parser, "").out == "['one', 'two']\n"
     assert run(parser, "--paths alpha").out == "['alpha']\n"
     assert run(parser, "--paths alpha beta gamma").out == "['alpha', 'beta', 'gamma']\n"
+
+
+def test_regression_issue224():
+    """
+    Issue #224: @arg param `dest` was ignored and Argh was unable to map the
+    declaration onto the function signature.
+
+    Use case: expose a function argument with a different name in the CLI.
+    """
+
+    @argh.arg("-l", dest="list_files")
+    def func(*, list_files=False):
+        return f"list_files={list_files}"
+
+    parser = DebugArghParser()
+    parser.set_default_command(func)
+
+    assert run(parser, "").out == "list_files=False\n"
+    assert run(parser, "-l").out == "list_files=True\n"