Ignore the "self" argument for methods in posargs2kwargs

Author: domdfcoding

domdf_python_tools/utils.py

@@ -69,6 +69,7 @@
 from io import StringIO
 from math import log10
 from pprint import pformat
+from types import MethodType
 from typing import TYPE_CHECKING, Any, Callable, Dict, Iterable, Iterator, List, Optional, Pattern, Tuple, Union
 
 # this package
@@ -249,16 +250,29 @@ def posargs2kwargs(
 	:default kwargs: ``{}``
 
 	:return: Dictionary mapping argument names to values.
+
+	.. versionchanged:: 2.8.0
+
+		The "self" argument for bound methods is ignored.
+		For unbound methods (which are just functions) the behaviour is unchanged.
 	"""
 
 	if kwargs is None:
 		kwargs = {}
 
-	if callable(posarg_names):
+	self_arg = None
+
+	if isinstance(posarg_names, MethodType):
+		posarg_names = inspect.getfullargspec(posarg_names).args
+		self_arg = posarg_names[0]
+	elif callable(posarg_names):
 		posarg_names = inspect.getfullargspec(posarg_names).args
 
 	kwargs.update(zip(posarg_names, args))
 
+	if self_arg is not None and self_arg in kwargs:
+		del kwargs[self_arg]
+
 	# TODO: positional only arguments
 
 	return kwargs

tests/test_utils.py

@@ -264,6 +264,9 @@ def demo_function(arg1, arg2, arg3):
 	pass
 
 
+cwd = pathlib.Path.cwd()
+
+
 @pytest.mark.parametrize(
 		"args, posarg_names, kwargs, expects",
 		[
@@ -275,6 +278,21 @@ def demo_function(arg1, arg2, arg3):
 						"arg2": 2,
 						"arg3": 3,
 						}),
+				((cwd, "wb", -1, "UTF-8"),
+					pathlib.Path.open,
+					None, {
+							"self": cwd,
+							"mode": "wb",
+							"buffering": -1,
+							"encoding": "UTF-8",
+							}),
+				((cwd, "wb", -1, "UTF-8"),
+					pathlib.Path().open,
+					None, {
+							"mode": "wb",
+							"buffering": -1,
+							"encoding": "UTF-8",
+							}),
 				]
 		)
 def test_posargs2kwargs(args, posarg_names, kwargs, expects):