address isinstance false negative when provided too many arguments

- add too-many-function-args call
- include handling for too-few-function-args

doc/whatsnew/fragments/9847.false_negative

@@ -0,0 +1,4 @@
+Fix a false negative when `isinstance` has too many arguments.
+Change now provides a `too-many-arguments` output with behavior similar to other `too-many-arguments` calls.
+
+Closes #9847

pylint/checkers/typecheck.py

@@ -255,7 +255,7 @@ def _missing_member_hint(
         "Used when a function call passes too few arguments.",
     ),
     "E1121": (
-        "Too many positional arguments for %s call",
+        "Too many positional arguments (%s/%s)",
         "too-many-function-args",
         "Used when a function call passes too many positional arguments.",
     ),
@@ -377,6 +377,11 @@ def _missing_member_hint(
         "Used when a slice step is 0 and the object doesn't implement "
         "a custom __getitem__ method.",
     ),
+    "E1145": (
+        "Too few positional arguments (%s/%s)",
+        "too-few-function-args",
+        "Used when a function or method has fewer arguments than expected.",
+    ),
     "W1113": (
         "Keyword argument before variable positional arguments list "
         "in the definition of %s function",
@@ -1420,8 +1425,21 @@ def _check_argument_order(
             self.add_message("arguments-out-of-order", node=node, args=())
 
     def _check_isinstance_args(self, node: nodes.Call) -> None:
-        if len(node.args) != 2:
-            # isinstance called with wrong number of args
+        if len(node.args) > 2:
+            # for when isinstance called with too many args
+            self.add_message(
+                "too-many-function-args",
+                node=node,
+                args=(len(node.args), 2),
+                confidence=HIGH,
+            )
+        elif len(node.args) < 2:
+            self.add_message(
+                "too-few-function-args",
+                node=node,
+                args=(len(node.args), 2),
+                confidence=HIGH,
+            )
             return
 
         second_arg = node.args[1]
@@ -1554,7 +1572,9 @@ def visit_call(self, node: nodes.Call) -> None:
             elif not overload_function:
                 # Too many positional arguments.
                 self.add_message(
-                    "too-many-function-args", node=node, args=(callable_name,)
+                    "too-many-function-args",
+                    node=node,
+                    args=(len(parameters), num_positional_args),
                 )
                 break
 

tests/functional/t/too/too_few_function_args.py

@@ -0,0 +1,3 @@
+# pylint: disable=missing-docstring
+
+isinstance(1) # [too-few-function-args]

tests/functional/t/too/too_few_function_args.txt

@@ -0,0 +1 @@
+too-few-function-args:3:0:3:13::Too few positional arguments (1/2):HIGH

tests/functional/t/too/too_many_arguments.txt

@@ -1,3 +1,3 @@
-too-many-arguments:4:0:4:19:stupid_function:Too many arguments (9/5):UNDEFINED
-too-many-positional-arguments:4:0:4:19:stupid_function:Too many positional arguments (9/5):HIGH
-too-many-arguments:37:0:37:9:name1:Too many arguments (6/5):UNDEFINED
+too-many-arguments:4:0:4:19:stupid_function:Too many arguments (9/5):UNDEFINED
+too-many-positional-arguments:4:0:4:19:stupid_function:Too many positional arguments (9/5):HIGH
+too-many-arguments:37:0:37:9:name1:Too many arguments (6/5):UNDEFINED

tests/functional/t/too/too_many_function_args.py

@@ -17,3 +17,8 @@ def main(param):
     if param == 0:
         tmp = add
     return tmp(1, 1.01)
+
+
+# Negative case, see `_check_isinstance_args` in `./pylint/checkers/typecheck.py`
+isinstance(1, int, int) # [too-many-function-args]
+isinstance(1, 1, int) # [too-many-function-args, isinstance-second-argument-not-valid-type]

tests/functional/t/too/too_many_function_args.txt

@@ -0,0 +1,3 @@
+too-many-function-args:23:0:23:23::Too many positional arguments (3/2):HIGH
+isinstance-second-argument-not-valid-type:24:0:24:21::Second argument of isinstance is not a type:INFERENCE
+too-many-function-args:24:0:24:21::Too many positional arguments (3/2):HIGH