Fix false positive for ``positional-only-arguments-expected`` when a function contains both a positional-only parameter that has a default value, and ``**kwargs``. (#8556) (#8560)

(cherry picked from commit db17860fd61154c59f3acc13ff34b120cc5ba091)

Co-authored-by: Mark Byrne <31762852+mbyrnepr2@users.noreply.github.com>

3 files changed, 23 insertions, 0 deletions

diff --git a/doc/whatsnew/fragments/8555.false_positive b/doc/whatsnew/fragments/8555.false_positive
new file mode 100644
index 000000000..157486b39
--- /dev/null
+++ b/doc/whatsnew/fragments/8555.false_positive
@@ -0,0 +1,3 @@
+Fix false positive for ``positional-only-arguments-expected`` when a function contains both a positional-only parameter that has a default value, and ``**kwargs``.
+
+Closes #8555
diff --git a/pylint/checkers/method_args.py b/pylint/checkers/method_args.py
index e88248219..8862328e3 100644
--- a/pylint/checkers/method_args.py
+++ b/pylint/checkers/method_args.py
@@ -111,6 +111,8 @@ class MethodArgsChecker(BaseChecker):
             and inferred_func.args.posonlyargs
         ):
             return
+        if inferred_func.args.kwarg:
+            return
         pos_args = [a.name for a in inferred_func.args.posonlyargs]
         kws = [k.arg for k in node.keywords if k.arg in pos_args]
         if not kws:
diff --git a/tests/functional/p/positional_only_arguments_expected.py b/tests/functional/p/positional_only_arguments_expected.py
index 7bde59ab8..98a2d65f5 100644
--- a/tests/functional/p/positional_only_arguments_expected.py
+++ b/tests/functional/p/positional_only_arguments_expected.py
@@ -16,3 +16,21 @@ cake.nihon(1, 2, i=3)  # [positional-only-arguments-expected]
 cake.nihon(1, r=2, i=3)  # [positional-only-arguments-expected]
 cake.nihon(a=1, r=2, i=3)  # [positional-only-arguments-expected]
 cake.nihon(1, r=2, i=3, cheese=True)  # [positional-only-arguments-expected]
+
+
+def function_with_kwargs(apple, banana="Yellow banana", /, **kwargs):
+    """
+    Calling this function with the `banana` keyword should not emit
+    `positional-only-arguments-expected` since it is added to `**kwargs`.
+
+    >>> function_with_kwargs("Red apple", banana="Green banana")
+    >>> "Red apple"
+    >>> "Yellow banana"
+    >>> {"banana": "Green banana"}
+    """
+    print(apple)
+    print(banana)
+    print(kwargs)
+
+
+function_with_kwargs("Red apple", banana="Green banana")