From df9f633f94e97fc43e0235cb2be076491ea7f67f Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Tue, 10 Jul 2018 00:48:57 -0700 Subject: bpo-33967: Fix singledispatch raised IndexError when no args (GH-8184) (cherry picked from commit 445f1b35ce8461268438c8a6b327ddc764287e05) Co-authored-by: Dong-hee Na --- Lib/functools.py | 5 +++++ Lib/test/test_functools.py | 7 +++++++ Misc/NEWS.d/next/Library/2018-07-08-18-49-41.bpo-33967.lhaAez.rst | 2 ++ 3 files changed, 14 insertions(+) create mode 100644 Misc/NEWS.d/next/Library/2018-07-08-18-49-41.bpo-33967.lhaAez.rst diff --git a/Lib/functools.py b/Lib/functools.py index c8b79c2..24b011d 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -817,8 +817,13 @@ def singledispatch(func): return func def wrapper(*args, **kw): + if not args: + raise TypeError(f'{funcname} requires at least ' + '1 positional argument') + return dispatch(args[0].__class__)(*args, **kw) + funcname = getattr(func, '__name__', 'singledispatch function') registry[object] = func wrapper.register = register wrapper.dispatch = dispatch diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py index 2245b97..e325480 100644 --- a/Lib/test/test_functools.py +++ b/Lib/test/test_functools.py @@ -2187,6 +2187,13 @@ class TestSingleDispatch(unittest.TestCase): )) self.assertTrue(str(exc.exception).endswith(msg_suffix)) + def test_invalid_positional_argument(self): + @functools.singledispatch + def f(*args): + pass + msg = 'f requires at least 1 positional argument' + with self.assertRaisesRegexp(TypeError, msg): + f() if __name__ == '__main__': unittest.main() diff --git a/Misc/NEWS.d/next/Library/2018-07-08-18-49-41.bpo-33967.lhaAez.rst b/Misc/NEWS.d/next/Library/2018-07-08-18-49-41.bpo-33967.lhaAez.rst new file mode 100644 index 0000000..1e1e745 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-07-08-18-49-41.bpo-33967.lhaAez.rst @@ -0,0 +1,2 @@ +functools.singledispatch now raises TypeError instead of IndexError when no +positional arguments are passed. -- cgit v0.12