bug - Fix method descriptor bug (#9)

* 🐛 - Fix method descriptor bug

* 🔖 - Bump up version to 1.0.2

flake8_force_keyword_arguments/util.py

@@ -2,7 +2,7 @@
 import inspect
 from enum import Enum
 from types import ModuleType
-from typing import Iterable, Optional, Set
+from typing import Any, Callable, Iterable, Optional, Set
 
 
 class QualifierOption(str, Enum):
@@ -67,12 +67,13 @@ def _list_pos_only_callables(
 
 def does_callable_have_poa_more_than(o: object, poa_threshold: int) -> bool:
     """POA: Positional Only Arguments"""
-    sig = get_invocation_signature(o)
-    if sig is None:
+    func = get_inspectable_function(o)
+    if func is None:
         return False
 
+    sig = inspect.signature(func)
     params = tuple(sig.parameters.values())
-    if len(params) > 0 and params[0].name in ('self', 'cls'):
+    if inspect.ismethoddescriptor(func) and len(params) > 0:
         params = params[1:]
 
     poa_count = 0
@@ -85,22 +86,28 @@ def does_callable_have_poa_more_than(o: object, poa_threshold: int) -> bool:
     return poa_count >= poa_threshold
 
 
-def get_invocation_signature(o: object) -> Optional[inspect.Signature]:
+def get_inspectable_function(o: object) -> Optional[Callable[..., Any]]:
     try:
-        return inspect.signature(o)  # type: ignore[arg-type]
+        inspect.signature(o)  # type: ignore[arg-type]
     except (ValueError, TypeError):
         pass
+    else:
+        return o  # type: ignore
 
     if inspect.isclass(o):
         try:
-            return inspect.signature(o.__init__)  # type: ignore[misc]
+            inspect.signature(o.__init__)  # type: ignore[misc]
         except (ValueError, TypeError):
             return None
+        else:
+            return o.__init__  # type: ignore[no-any-return,misc]
     elif callable(o):
         try:
-            return inspect.signature(o.__call__)
+            inspect.signature(o.__call__)
         except (ValueError, TypeError):
             return None
+        else:
+            return o.__call__
     return None
 
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "flake8-force-keyword-arguments"
-version = "1.0.1"
+version = "1.0.2"
 description = "A flake8 extension that is looking for function calls and forces to use keyword arguments if there are more than X arguments"
 authors = ["Viktor Chaptsev <viktor@chaptsev.ru>", "Byeonghoon Yoo <bh322yoo@gmail.com>"]
 maintainers = ["Byeonghoon Yoo <bh322yoo@gmail.com>"]

tests/test_util.py

@@ -1,11 +1,10 @@
 import ast
-import inspect
+import sys
 from functools import partial
 from textwrap import dedent
 from typing import Set
 
 import pytest
-import sys
 
 from flake8_force_keyword_arguments import util
 
@@ -33,79 +32,24 @@ def test_get_invocation_line(source_code: str, expected: str) -> None:
 
 
 @pytest.mark.parametrize(
-    ('obj', 'expected'),
+    ('obj', 'expected_attribute_name'),
     (
         (1, None),
         ('qwr', None),
-        (
-            int,
-            inspect.Signature(
-                (
-                    inspect.Parameter(
-                        'self',
-                        kind=inspect.Parameter.POSITIONAL_ONLY,
-                    ),
-                    inspect.Parameter(
-                        'args',
-                        kind=inspect.Parameter.VAR_POSITIONAL,
-                    ),
-                    inspect.Parameter(
-                        'kwargs',
-                        kind=inspect.Parameter.VAR_KEYWORD,
-                    ),
-                )
-            ),
-        ),
-        (
-            getattr,
-            inspect.Signature(
-                (
-                    inspect.Parameter(
-                        'args',
-                        kind=inspect.Parameter.VAR_POSITIONAL,
-                    ),
-                    inspect.Parameter(
-                        'kwargs',
-                        kind=inspect.Parameter.VAR_KEYWORD,
-                    ),
-                )
-            ),
-        ),
-        (
-            type('TestClass', (), dict(__init__=lambda self, a, b: None)),
-            inspect.Signature(
-                (
-                    inspect.Parameter(
-                        'a',
-                        kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
-                    ),
-                    inspect.Parameter(
-                        'b',
-                        kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
-                    ),
-                )
-            ),
-        ),
-        (
-            type('TestClass', (), dict(__init__=lambda self: None)),
-            inspect.Signature(()),
-        ),
-        (
-            lambda c: None,
-            inspect.Signature((inspect.Parameter('c', kind=inspect.Parameter.POSITIONAL_OR_KEYWORD),)),
-        ),
-        (
-            partial(lambda c, d: None, 1),
-            inspect.Signature((inspect.Parameter('d', kind=inspect.Parameter.POSITIONAL_OR_KEYWORD),)),
-        ),
-        (
-            type('TestClass', (), dict(__call__=lambda self, a: None))(),
-            inspect.Signature((inspect.Parameter('a', kind=inspect.Parameter.POSITIONAL_OR_KEYWORD),)),
-        ),
+        (int, '__init__'),
+        (getattr, '__call__'),
+        (type('TestClass', (), dict(__init__=lambda self, a, b: None)), '$self$'),
+        (lambda c: None, '$self$'),
+        (type('TestClass', (), dict(__call__=lambda self, a: None))(), '$self$'),
     ),
 )
-def test_get_invocation_signature(obj: object, expected: inspect.Signature) -> None:
-    assert util.get_invocation_signature(obj) == expected
+def test_get_inspectable_function(obj, expected_attribute_name):
+    if expected_attribute_name == '$self$':
+        assert util.get_inspectable_function(obj) == obj
+    elif expected_attribute_name is None:
+        assert util.get_inspectable_function(obj) is None
+    else:
+        assert util.get_inspectable_function(obj) == getattr(obj, expected_attribute_name)
 
 
 @pytest.mark.parametrize(
@@ -137,6 +81,9 @@ def test_get_invocation_signature(obj: object, expected: inspect.Signature) -> N
         (type('TestClass', (), dict(__call__=lambda self, a: None))(), 0, True),
         (type('TestClass', (), dict(__call__=lambda self, a: None))(), 1, False),
         (type('TestClass', (), dict(__call__=lambda self, a: None))(), 2, False),
+        (issubclass, 0, True),
+        (issubclass, 1, True),
+        (issubclass, 2, True),
     ),
 )
 def test_does_callable_have_poa_more_than(obj: object, threshold: int, expected: bool) -> None: