Skip empty classes while inspecting fields order (incl inherited) (PY-40018)

GitOrigin-RevId: 53ce68c45df4049346c67416d250b2e36e2c762c

python/src/com/jetbrains/python/inspections/PyNamedTupleInspection.kt

@@ -31,10 +31,20 @@ class PyNamedTupleInspection : PyInspection() {
 
       val ancestors = cls.getAncestorClasses(context)
       val ancestorsFields = ancestors.map {
-        when {
-          !classFieldsFilter(it) -> Ancestor.FILTERED
-          processFields(it, fieldsFilter, hasAssignedValue).fieldsWithDefaultValue.isNotEmpty() -> Ancestor.HAS_FIELD_WITH_DEFAULT_VALUE
-          else -> Ancestor.HAS_NOT_FIELD_WITH_DEFAULT_VALUE
+        if (!classFieldsFilter(it)) {
+          Ancestor.FILTERED
+        }
+        else {
+          val processor = processFields(it, fieldsFilter, hasAssignedValue)
+          if (processor.fieldsWithDefaultValue.isNotEmpty()) {
+            Ancestor.HAS_FIELD_WITH_DEFAULT_VALUE
+          }
+          else if (processor.lastFieldWithoutDefaultValue != null) {
+            Ancestor.HAS_NOT_FIELD_WITH_DEFAULT_VALUE
+          }
+          else {
+            Ancestor.FILTERED
+          }
         }
       }
 

python/testData/inspections/PyDataclassInspection/inheritingDefaultArgumentThroughEmptyDataclass.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+
+@dataclass
+class AnimalClass:
+    number_legs: int = None
+
+@dataclass
+class MamaClass(AnimalClass):
+    pass
+
+@dataclass
+class CatClass(MamaClass):
+    pet_name: str = None

python/testSrc/com/jetbrains/python/inspections/PyDataclassInspectionTest.java

@@ -296,6 +296,11 @@ public class PyDataclassInspectionTest extends PyInspectionTestCase {
     doTest();
   }
 
+  // PY-40018
+  public void testInheritingDefaultArgumentThroughEmptyDataclass() {
+    doTest();
+  }
+
   @Override
   protected void doTest() {
     runWithLanguageLevel(