inspect.signature: Check for function-like objects before builtins. Issue #17159
diff --git a/Lib/inspect.py b/Lib/inspect.py
index b85fbcc..c7a2cf8 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -1911,15 +1911,15 @@
return sig.replace(parameters=new_params)
- if _signature_is_builtin(obj):
- return _signature_from_builtin(Signature, obj,
- skip_bound_arg=skip_bound_arg)
-
if isfunction(obj) or _signature_is_functionlike(obj):
# If it's a pure Python function, or an object that is duck type
# of a Python function (Cython functions, for instance), then:
return Signature.from_function(obj)
+ if _signature_is_builtin(obj):
+ return _signature_from_builtin(Signature, obj,
+ skip_bound_arg=skip_bound_arg)
+
if isinstance(obj, functools.partial):
wrapped_sig = _signature_internal(obj.func,
follow_wrapper_chains,
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 95c1b32..0dc7451 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -14,6 +14,7 @@
import types
import unicodedata
import unittest
+import unittest.mock
try:
from concurrent.futures import ThreadPoolExecutor
@@ -1836,6 +1837,21 @@
('kwargs', ..., ..., "var_keyword")),
...))
+ # Test with cython-like builtins:
+ _orig_isdesc = inspect.ismethoddescriptor
+ def _isdesc(obj):
+ if hasattr(obj, '_builtinmock'):
+ return True
+ return _orig_isdesc(obj)
+
+ with unittest.mock.patch('inspect.ismethoddescriptor', _isdesc):
+ builtin_func = funclike(func)
+ # Make sure that our mock setup is working
+ self.assertFalse(inspect.ismethoddescriptor(builtin_func))
+ builtin_func._builtinmock = True
+ self.assertTrue(inspect.ismethoddescriptor(builtin_func))
+ self.assertEqual(inspect.signature(builtin_func), sig_func)
+
def test_signature_functionlike_class(self):
# We only want to duck type function-like objects,
# not classes.