Make dataclasses/attrs comparison recursive, fixes #4675

testing/example_scripts/dataclasses/test_compare_recursive_dataclasses.py

@@ -0,0 +1,34 @@
+from dataclasses import dataclass
+from dataclasses import field
+
+
+@dataclass
+class SimpleDataObject:
+    field_a: int = field()
+    field_b: int = field()
+
+
+@dataclass
+class ComplexDataObject2:
+    field_a: SimpleDataObject = field()
+    field_b: SimpleDataObject = field()
+
+
+@dataclass
+class ComplexDataObject:
+    field_a: SimpleDataObject = field()
+    field_b: ComplexDataObject2 = field()
+
+
+def test_recursive_dataclasses():
+
+    left = ComplexDataObject(
+        SimpleDataObject(1, "b"),
+        ComplexDataObject2(SimpleDataObject(1, "b"), SimpleDataObject(2, "c"),),
+    )
+    right = ComplexDataObject(
+        SimpleDataObject(1, "b"),
+        ComplexDataObject2(SimpleDataObject(1, "b"), SimpleDataObject(3, "c"),),
+    )
+
+    assert left == right