Fix crash with dataclasses that have __init_subclass__ modifying __init__

Co-authored-by: Pierre-Sassoulas <[email protected]>

Author: Copilot

pylint/checkers/dataclass_checker.py

@@ -14,6 +14,52 @@
 from pylint.checkers import BaseChecker, utils
 from pylint.interfaces import INFERENCE
 
+
+# Monkey patch to fix astroid issue with __init_subclass__ modifying __init__
+# See: https://github.com/pylint-dev/pylint/issues/10519
+def _patched_find_arguments_from_base_classes(node):
+    """Patched version that handles AssignAttr nodes in __init__."""
+    import astroid.brain.brain_dataclasses as brain_dataclasses_module
+    
+    # Get the original function implementation
+    orig_func = brain_dataclasses_module._find_arguments_from_base_classes.__wrapped__ if hasattr(brain_dataclasses_module._find_arguments_from_base_classes, '__wrapped__') else brain_dataclasses_module._find_arguments_from_base_classes
+    
+    pos_only_store = {}
+    kw_only_store = {}
+    
+    for base in reversed(node.mro()):
+        if not base.is_dataclass:
+            continue
+        try:
+            base_init = base.locals["__init__"][0]
+        except KeyError:
+            continue
+
+        # Check if base_init is actually a FunctionDef node
+        # When __init_subclass__ modifies __init__ by assignment, it becomes an AssignAttr node
+        if not isinstance(base_init, nodes.FunctionDef):
+            continue
+
+        pos_only, kw_only = base_init.args._get_arguments_data()
+        for posarg, data in pos_only.items():
+            pos_only_store[posarg] = data
+
+        for kwarg, data in kw_only.items():
+            kw_only_store[kwarg] = data
+    
+    return pos_only_store, kw_only_store
+
+
+# Apply the monkey patch
+try:
+    import astroid.brain.brain_dataclasses as brain_dataclasses_module
+    if not hasattr(brain_dataclasses_module._find_arguments_from_base_classes, '__wrapped__'):
+        brain_dataclasses_module._find_arguments_from_base_classes.__wrapped__ = brain_dataclasses_module._find_arguments_from_base_classes
+    brain_dataclasses_module._find_arguments_from_base_classes = _patched_find_arguments_from_base_classes
+except ImportError:
+    # astroid.brain.brain_dataclasses might not be available in all versions
+    pass
+
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 

test_issue.py renamed to tests/functional/d/dataclass/dataclass_generic_init_subclass.py

@@ -1,4 +1,4 @@
-"""Playground file. Do not commit"""
+"""Test for issue #10519: Crash with generic dataclass that has __init_subclass__"""
 
 from abc import ABC
 from collections.abc import Callable
@@ -10,6 +10,7 @@
 
 @dataclass
 class Foo[T](ABC):
+    """A generic dataclass with __init_subclass__ that modifies __init__"""
 
     _foo: T | None = field(init=False)
     _bar: dict[str, str] = field(init=False)
@@ -30,4 +31,10 @@ def _w(*args: _P.args, **kwds: _P.kwargs) -> None:
 
 
 @dataclass
-class Bar(Foo): ...
+class Bar(Foo):
+    """A subclass of the generic dataclass without type parameter"""
+
+
+@dataclass
+class Baz(Foo[str]):
+    """A subclass of the generic dataclass with type parameter"""