Declare function mutators with inline comment

This is accomplised by defining an "error" called decorator-preserves-signature
which, when disabled via a comment on a decorator definition, will disable
function argument checks on calls to functions that have that decorator. We
use an error to do this in order to consume the inline comment state via the
linter.file_state._supression_mapping

.gitignore

@@ -27,3 +27,4 @@ build-stamp
 .pytest_cache/
 .mypy_cache/
 .benchmarks/
+venv

pylint/checkers/typecheck.py

@@ -381,6 +381,11 @@ def _missing_member_hint(
  "Used when a slice step is 0 and the object doesn't implement "
  "a custom __getitem__ method.",
  ),
+ "E1145": (
+ "",
+ "decorator-preserves-signature",
+ "Ignore invalid argument errors on calls to this function",
+ ),
  "W1113": (
  "Keyword argument before variable positional arguments list "
  "in the definition of %s function",
@@ -1454,10 +1459,19 @@ def visit_call(self, node: nodes.Call) -> None:
  return
 
  # Has the function signature changed in ways we cannot reliably detect?
- if hasattr(called, "decorators") and decorated_with(
- called, self.linter.config.signature_mutators
- ):
- return
+ if getattr(called, "decorators", None):
+ if decorated_with(called, self.linter.config.signature_mutators):
+ return
+
+ for called_decorator in filter(
+ None, map(safe_infer, called.decorators.nodes)
+ ):
+ if decorated_with(called, ["yet_another_mutation_decorator"]):
+ print(self.linter.file_state._module_msgs_state.get("E1145", {}))
+ if not self.linter.file_state._module_msgs_state.get("E1145", {}).get(
+ called_decorator.lineno, True
+ ):
+ return
 
  num_positional_args = len(call_site.positional_arguments)
  keyword_args = list(call_site.keyword_arguments.keys())

tests/functional/a/arguments.py

@@ -240,6 +240,17 @@ def wrapper(*args, do_something=True, **kwargs):
  return wrapper
 
 
+def yet_another_mutation_decorator(fun): # pylint: disable=decorator-preserves-signature
+ """Yet another decorator that changes a function's signature"""
+ def wrapper(*args, do_something=True, **kwargs):
+ if do_something:
+ return fun(*args, **kwargs)
+
+ return None
+
+ return wrapper
+
+
 @mutation_decorator
 def mutated_function(arg):
  return arg
@@ -250,11 +261,17 @@ def mutated(arg):
  return arg
 
 
+@yet_another_mutation_decorator
+def another_mutated_function(arg):
+ return arg
+
+
 mutated_function(do_something=False)
 mutated_function()
 
 mutated(do_something=True)
 
+another_mutated_function(do_something=False)
 
 def func(one, two, three):
  return one + two + three