fix: Don't turn items annotated as InitVar into dataclass members

PR-252: #252

src/griffe/extensions/dataclasses.py

@@ -176,13 +176,22 @@ def _set_dataclass_init(class_: Class) -> None:
     class_.set_member("__init__", init)
 
 
+def _del_members_annotated_as_initvar(class_: Class) -> None:
+    # Definitions annotated as InitVar are not class members
+    attributes = [member for member in class_.members.values() if isinstance(member, Attribute)]
+    for attribute in attributes:
+        if isinstance(attribute.annotation, Expr) and attribute.annotation.canonical_path == "dataclasses.InitVar":
+            class_.del_member(attribute.name)
+
+
 def _apply_recursively(mod_cls: Module | Class, processed: set[str]) -> None:
     if mod_cls.canonical_path in processed:
         return
     processed.add(mod_cls.canonical_path)
     if isinstance(mod_cls, Class):
         if "__init__" not in mod_cls.members:
             _set_dataclass_init(mod_cls)
+            _del_members_annotated_as_initvar(mod_cls)
         for member in mod_cls.members.values():
             if not member.is_alias and member.is_class:
                 _apply_recursively(member, processed)  # type: ignore[arg-type]

tests/test_dataclasses.py

@@ -276,3 +276,36 @@ class Reordered(Base):
         assert [p.name for p in params_base] == ["self", "a", "b"]
         assert [p.name for p in params_reordered] == ["self", "b", "c", "a"]
         assert str(params_reordered["b"].annotation) == "float"
+
+
+def test_parameters_annotated_as_initvar() -> None:
+    """Don't return InitVar annotated fields as class members.
+
+    But if __init__ is defined, InitVar has no effect.
+    """
+    code = """
+    from dataclasses import dataclass, InitVar
+
+    @dataclass
+    class PointA:
+        x: float
+        y: float
+        z: InitVar[float]
+
+    @dataclass
+    class PointB:
+        x: float
+        y: float
+        z: InitVar[float]
+
+        def __init__(self, r: float): ...
+    """
+
+    with temporary_visited_package("package", {"__init__.py": code}) as module:
+        point_a = module["PointA"]
+        assert ["self", "x", "y", "z"] == [p.name for p in point_a.parameters]
+        assert ["x", "y", "__init__"] == list(point_a.members)
+
+        point_b = module["PointB"]
+        assert ["self", "r"] == [p.name for p in point_b.parameters]
+        assert ["x", "y", "z", "__init__"] == list(point_b.members)