bpo-38478: Correctly handle keyword argument with same name as positional-only parameter (GH-16800)

miss-islington · pablogsal · web-flow · commit f705f8e9b589 · 2019-10-15T05:02:34.000-07:00
(cherry picked from commit f3ef06a) Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Lib/inspect.py b/Lib/inspect.py
@@ -2960,7 +2960,7 @@ def _bind(self, args, kwargs, *, partial=False):
                         arguments[param.name] = tuple(values)
                         break
 
-                    if param.name in kwargs:
+                    if param.name in kwargs and param.kind != _POSITIONAL_ONLY:
                         raise TypeError(
                             'multiple values for argument {arg!r}'.format(
                                 arg=param.name)) from None
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
@@ -3577,6 +3577,16 @@ def make_set():
         iterator = iter(range(5))
         self.assertEqual(self.call(setcomp_func, iterator), {0, 1, 4, 9, 16})
 
+    def test_signature_bind_posonly_kwargs(self):
+        def foo(bar, /, **kwargs):
+            return bar, kwargs.get(bar)
+
+        sig = inspect.signature(foo)
+        result = sig.bind("pos-only", bar="keyword")
+
+        self.assertEqual(result.kwargs, {"bar": "keyword"})
+        self.assertIn(("bar", "pos-only"), result.arguments.items())
+
 
 class TestBoundArguments(unittest.TestCase):
     def test_signature_bound_arguments_unhashable(self):
diff --git a/Misc/NEWS.d/next/Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst b/Misc/NEWS.d/next/Library/2019-10-15-11-37-57.bpo-38478.A87OPO.rst
@@ -0,0 +1,3 @@
+Fixed a bug in :meth:`inspect.signature.bind` that was causing it to fail
+when handling a keyword argument with same name as positional-only parameter.
+Patch by Pablo Galindo.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+Fixed a bug in :meth:`inspect.signature.bind` that was causing it to fail
	`2`	`+when handling a keyword argument with same name as positional-only parameter.`
	`3`	`+Patch by Pablo Galindo.`