Move B042 to B913 to not be enabled by deefault due to false positives

README.rst

@@ -288,7 +288,7 @@ second usage. Save the result to a list if the result is needed multiple times.
 
 **B041**: Repeated key-value pair in dictionary literal. Only emits errors when the key's value is *also* the same, being the opposite of the pyflakes like check.
 
-**B042**: Remember to call super().__init__() in custom exceptions initalizer.
+**B042**: Reserved for future use. This check has been moved to B913.
 
 Opinionated warnings
 ~~~~~~~~~~~~~~~~~~~~
@@ -372,6 +372,11 @@ The ``strict=`` argument was added in Python 3.13, so don't enable this flag for
 **B912**: ``map()`` without an explicit `strict=` parameter set. ``strict=True`` causes the resulting iterator
 to raise a ``ValueError`` if the arguments are exhausted at differing lengths.
 
+.. _B913:
+
+**B913**: Exception class with ``__init__`` should pass all args to ``super().__init__()`` in order to work
+with ``copy.copy()``. It should also not take any kwargs.
+
 .. _B950:
 
 **B950**: Line too long. This is a pragmatic equivalent of
@@ -479,10 +484,15 @@ MIT
 Change Log
 ----------
 
+UNRELEASED
+~~~~~~~~~~
+
+* B913: Move B042 to be optional by default. It checks for reminding to call super().__init__ in custom exceptions
+
 25.10.21
 ~~~~~~~~~~
 
-* B042: New check for reminding to call super().__init__ in custom exceptions
+* B042: New check for reminding to call super().__init__ in custom exceptions (moved to B913, B042 reserved for future use)
 * B028: Skip if skip_file_prefixes is used (#503)
 * B912: New check for `map()` without an explicit `strict=` parameter. (#516)
 * Add python3.14 Support / CI

bugbear.py

@@ -614,7 +614,7 @@ def visit_ClassDef(self, node: ast.ClassDef) -> None:
         self.check_for_b903(node)
         self.check_for_b021(node)
         self.check_for_b024_and_b027(node)
-        self.check_for_b042(node)
+        self.check_for_b913(node)
         self.generic_visit(node)
 
     def visit_Try(self, node) -> None:
@@ -1733,7 +1733,7 @@ def check(num_args: int, param_name: str) -> None:
         elif func.attr == "split":
             check(2, "maxsplit")
 
-    def check_for_b042(self, node: ast.ClassDef) -> None:  # noqa: C901 # too-complex
+    def check_for_b913(self, node: ast.ClassDef) -> None:  # noqa: C901 # too-complex
         def is_exception(s: str):
             for ending in "Exception", "Error", "Warning", "ExceptionGroup":
                 if s.endswith(ending):
@@ -1755,7 +1755,7 @@ def is_exception(s: str):
                 continue
             if fun.args.kwonlyargs or fun.args.kwarg:
                 # kwargs cannot be passed to super().__init__()
-                self.add_error("B042", fun)
+                self.add_error("B913", fun)
                 return
             # -1 to exclude the `self` argument
             expected_arg_count = (
@@ -1782,18 +1782,18 @@ def is_exception(s: str):
                     and b.value.func.attr == "__init__"
                 ):
                     if len(b.value.args) != expected_arg_count:
-                        self.add_error("B042", fun)
+                        self.add_error("B913", fun)
                     elif fun.args.vararg:
                         for arg in b.value.args:
                             if isinstance(arg, ast.Starred):
                                 return
                         else:
                             # no Starred argument despite vararg
-                            self.add_error("B042", fun)
+                            self.add_error("B913", fun)
                     return
             else:
                 # no super().__init__() found
-                self.add_error("B042", fun)
+                self.add_error("B913", fun)
                 return
         # no `def __init__` found, which is fine
 
@@ -2408,13 +2408,6 @@ def __call__(self, lineno: int, col: int, vars: tuple[object, ...] = ()) -> erro
         message="B040 Exception with added note not used. Did you forget to raise it?"
     ),
     "B041": Error(message=("B041 Repeated key-value pair in dictionary literal.")),
-    "B042": Error(
-        message=(
-            "B042 Exception class with `__init__` should pass all args to "
-            "`super().__init__()` in order to work with `copy.copy()`. "
-            "It should also not take any kwargs."
-        )
-    ),
     # Warnings disabled by default.
     "B901": Error(
         message=(
@@ -2477,6 +2470,13 @@ def __call__(self, lineno: int, col: int, vars: tuple[object, ...] = ()) -> erro
         message="B911 `itertools.batched()` without an explicit `strict=` parameter."
     ),
     "B912": Error(message="B912 `map()` without an explicit `strict=` parameter."),
+    "B913": Error(
+        message=(
+            "B913 Exception class with `__init__` should pass all args to "
+            "`super().__init__()` in order to work with `copy.copy()`. "
+            "It should also not take any kwargs."
+        )
+    ),
     "B950": Error(message="B950 line too long ({} > {} characters)"),
 }
 
@@ -2493,5 +2493,6 @@ def __call__(self, lineno: int, col: int, vars: tuple[object, ...] = ()) -> erro
     "B910",
     "B911",
     "B912",
+    "B913",
     "B950",
 ]

tests/eval_files/b042.py → tests/eval_files/b913.py

@@ -9,17 +9,17 @@ def __init__(self, foo, bar=3):
 
 
 class MyError_args_bad(Exception):
-    def __init__(self, foo, bar=3):  # B042: 4
+    def __init__(self, foo, bar=3):  # B913: 4
         super().__init__(foo)
 
 
 class MyError_kwonlyargs(Exception):
-    def __init__(self, *, foo):  # B042: 4
+    def __init__(self, *, foo):  # B913: 4
         super().__init__(foo=foo)
 
 
 class MyError_kwargs(Exception):
-    def __init__(self, **kwargs):  # B042: 4
+    def __init__(self, **kwargs):  # B913: 4
         super().__init__(**kwargs)
 
 
@@ -29,16 +29,16 @@ def __init__(self, *args):  # safe
 
 
 class MyError_vararg_bad(Exception):
-    def __init__(self, *args):  # B042: 4
+    def __init__(self, *args):  # B913: 4
         super().__init__()
 
 
 class MyError_args_nothing(Exception):
-    def __init__(self, *args): ...  # B042: 4
+    def __init__(self, *args): ...  # B913: 4
 
 
 class MyError_nested_init(Exception):
-    def __init__(self, x):  # B042: 4
+    def __init__(self, x):  # B913: 4
         if True:
             super().__init__(x)
 
@@ -50,22 +50,22 @@ def __init__(self, x, /, y):
 # if it inherits from a class whose name ends with, any of
 # 'Error', 'Exception', 'ExceptionGroup', 'Warning', 'ExceptionGroup'
 class Anything(ValueError):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 class Anything2(BaseException):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 class Anything3(ExceptionGroup):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 class Anything4(UserWarning):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 
 class MyError(Anything):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 class MyException(Anything):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 class MyExceptionGroup(Anything):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 class MyWarning(Anything):
-    def __init__(self, x): ...  # B042: 4
+    def __init__(self, x): ...  # B913: 4
 
 class ExceptionHandler(Anything):
     def __init__(self, x): ...  # safe