WPS230: Allow any number of attributes in @dataclass, closes #2448

CHANGELOG.md

@@ -86,6 +86,7 @@ Semantic versioning in our case means:
 - Allows underscores (`_`) with exactly 3 digits after it in `WPS303`, #3120
 - Allows class / instance attribute shadowing
   in `@dataclass`es for `WPS601`, #1926
+- Allows any number of instance attributes on `@dataclass`es in `WPS230`, #2448
 - Adds new rule to forbid `lambda` assigns to special attributes, #1733
 - Adds new rule to check problematic function params, #1343
 - Adds new rule to detect duplicate conditions in `if`s and `elif`s, #2241

tests/test_visitors/test_ast/test_complexity/test_classes/test_public_attrs_count.py

@@ -16,6 +16,26 @@ def other(self):
         {1}
 """
 
+dataclass_template = """
+@dataclass
+class Test:
+    def __init__(self):
+        {0}
+
+    def other(self):
+        {1}
+"""
+
+not_a_dataclass_template = """
+@not_a_dataclass
+class Test:
+    def __init__(self):
+        {0}
+
+    def other(self):
+        {1}
+"""
+
 module_template = """
 {0}
 {1}
@@ -32,6 +52,8 @@ def some():
     'code',
     [
         class_template,
+        dataclass_template,
+        not_a_dataclass_template,
         module_template,
         function_template,
     ],
@@ -78,6 +100,7 @@ def test_correct_attributes(
     'code',
     [
         class_template,
+        not_a_dataclass_template,
     ],
 )
 @pytest.mark.parametrize(
@@ -112,6 +135,7 @@ def test_wrong_attributes_count(
 @pytest.mark.parametrize(
     'code',
     [
+        dataclass_template,
         module_template,
         function_template,
     ],

wemake_python_styleguide/violations/complexity.py

@@ -1007,6 +1007,8 @@ class TooManyPublicAttributesViolation(ASTViolation):
         https://en.wikipedia.org/wiki/Coupling_(computer_programming)
 
     .. versionadded:: 0.12.0
+    .. versionchanged:: 1.0.0
+       Any amount of attributes are allowed on ``@dataclasses``.
 
     """
 

wemake_python_styleguide/visitors/ast/complexity/classes.py

@@ -53,6 +53,9 @@ def _check_base_classes(self, node: ast.ClassDef) -> None:
             )
 
     def _check_public_attributes(self, node: ast.ClassDef) -> None:
+        if classes.is_dataclass(node):
+            return  # dataclasses can have any amount of attributes
+
         _, instance_attributes = classes.get_attributes(
             node,
             include_annotated=False,