From b6afc789fbe7bf23a43742f1bf480bb50d188710 Mon Sep 17 00:00:00 2001
From: Christodoulos Tsoulloftas <chris@komposta.net>
Date: Tue, 16 Apr 2024 19:59:43 +0300
Subject: [PATCH 1/4] feat: Navigate from inner to outer classes

---
 .../handlers/test_validate_references.py      | 34 +++++++++++++++++
 tests/codegen/test_container.py               |  3 ++
 .../codegen/handlers/disambiguate_choices.py  |  1 +
 .../codegen/handlers/unnest_inner_classes.py  |  1 +
 .../codegen/handlers/validate_references.py   | 37 ++++++++++++++++++-
 xsdata/codegen/mappers/definitions.py         |  1 +
 xsdata/codegen/mappers/dict.py                |  1 +
 xsdata/codegen/mappers/dtd.py                 |  2 +-
 xsdata/codegen/mappers/element.py             |  1 +
 xsdata/codegen/mappers/schema.py              |  1 +
 xsdata/codegen/models.py                      |  2 +
 xsdata/codegen/utils.py                       |  2 +
 12 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/tests/codegen/handlers/test_validate_references.py b/tests/codegen/handlers/test_validate_references.py
index 18b35d8c9..da773b6b9 100644
--- a/tests/codegen/handlers/test_validate_references.py
+++ b/tests/codegen/handlers/test_validate_references.py
@@ -60,3 +60,37 @@ def test_validate_misrepresented_references(self):
 
         with self.assertRaises(CodegenError):
             self.handler.run()
+
+    def test_validate_parent_references_with_root_class_with_parent(self):
+        target = ClassFactory.create()
+        target.parent = ClassFactory.create()
+        self.container.add(target)
+
+        with self.assertRaises(CodegenError):
+            self.handler.run()
+
+    def test_validate_parent_references_with_wrong_parent(self):
+        parent = ClassFactory.create()
+        child = ClassFactory.create()
+        wrong = ClassFactory.create()
+
+        parent.inner.append(child)
+        child.parent = wrong
+
+        self.container.extend([parent, wrong])
+
+        with self.assertRaises(CodegenError):
+            self.handler.run()
+
+    def test_validate_parent_references_with_wrong_parent_ref(self):
+        parent = ClassFactory.create()
+        child = ClassFactory.create()
+        wrong = parent.clone()
+
+        parent.inner.append(child)
+        child.parent = wrong
+
+        self.container.extend([parent])
+
+        with self.assertRaises(CodegenError):
+            self.handler.run()
diff --git a/tests/codegen/test_container.py b/tests/codegen/test_container.py
index a4804d80f..cdf9a5880 100644
--- a/tests/codegen/test_container.py
+++ b/tests/codegen/test_container.py
@@ -114,6 +114,9 @@ def test_process_class(self):
         target = ClassFactory.create(
             inner=[ClassFactory.elements(2), ClassFactory.elements(1)]
         )
+        for inner in target.inner:
+            inner.parent = target
+
         self.container.add(target)
 
         self.container.process()
diff --git a/xsdata/codegen/handlers/disambiguate_choices.py b/xsdata/codegen/handlers/disambiguate_choices.py
index d491abf72..f94628a0e 100644
--- a/xsdata/codegen/handlers/disambiguate_choices.py
+++ b/xsdata/codegen/handlers/disambiguate_choices.py
@@ -171,6 +171,7 @@ def disambiguate_choice(self, target: Class, choice: Attr):
         if not inner:
             self.container.add(ref_class)
         else:
+            ref_class.parent = target
             target.inner.append(ref_class)
 
     def is_simple_type(self, choice: Attr) -> bool:
diff --git a/xsdata/codegen/handlers/unnest_inner_classes.py b/xsdata/codegen/handlers/unnest_inner_classes.py
index 4b38d8cf1..bc1d8e751 100644
--- a/xsdata/codegen/handlers/unnest_inner_classes.py
+++ b/xsdata/codegen/handlers/unnest_inner_classes.py
@@ -60,6 +60,7 @@ def clone_class(cls, inner: Class, name: str) -> Class:
             The new class instance
         """
         clone = inner.clone()
+        clone.parent = None
         clone.local_type = True
         clone.qname = build_qname(inner.target_namespace, f"{name}_{inner.name}")
 
diff --git a/xsdata/codegen/handlers/validate_references.py b/xsdata/codegen/handlers/validate_references.py
index 5403ab6b1..de6dff404 100644
--- a/xsdata/codegen/handlers/validate_references.py
+++ b/xsdata/codegen/handlers/validate_references.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import Optional, Set
 
 from xsdata.codegen.exceptions import CodegenError
 from xsdata.codegen.mixins import ContainerHandlerInterface
@@ -21,6 +21,7 @@ def run(self):
         self.validate_unique_qualified_names()
         self.validate_unique_instances()
         self.validate_resolved_references()
+        self.validate_parent_references()
 
     def validate_unique_qualified_names(self):
         """Validate all root classes have unique qualified names."""
@@ -71,3 +72,37 @@ def build(target: Class):
                     raise CodegenError(
                         "Misrepresented reference", cls=item.qname, type=tp.qname
                     )
+
+    def validate_parent_references(self):
+        """Validate inner to outer classes is accurate."""
+
+        def _validate(target: Class, parent: Optional[Class] = None):
+            actual_qname = actual_ref = expected_qname = expected_ref = None
+            if target.parent:
+                actual_qname = target.parent.qname
+                actual_ref = target.parent.ref
+
+            if parent:
+                expected_qname = parent.qname
+                expected_ref = parent.ref
+
+            if actual_qname != expected_qname:
+                raise CodegenError(
+                    "Invalid parent class reference",
+                    cls=target.qname,
+                    expected=expected_qname,
+                    actual=actual_qname,
+                )
+
+            if actual_ref != expected_ref:
+                raise CodegenError(
+                    "Invalid parent class reference",
+                    cls=target.qname,
+                    ref=actual_qname,
+                )
+
+            for inner in target.inner:
+                _validate(inner, target)
+
+        for item in self.container:
+            _validate(item)
diff --git a/xsdata/codegen/mappers/definitions.py b/xsdata/codegen/mappers/definitions.py
index a7effce21..1a5f8a884 100644
--- a/xsdata/codegen/mappers/definitions.py
+++ b/xsdata/codegen/mappers/definitions.py
@@ -376,6 +376,7 @@ def build_inner_class(
             )
             attr = cls.build_attr(name, inner.qname, forward=True, namespace=namespace)
 
+            inner.parent = target
             target.inner.append(inner)
             target.attrs.append(attr)
 
diff --git a/xsdata/codegen/mappers/dict.py b/xsdata/codegen/mappers/dict.py
index a62be0ba4..8aae9b09d 100644
--- a/xsdata/codegen/mappers/dict.py
+++ b/xsdata/codegen/mappers/dict.py
@@ -66,6 +66,7 @@ def build_class_attribute(cls, target: Class, name: str, value: Any):
         else:
             if isinstance(value, dict):
                 inner = cls.build_class(value, name)
+                inner.parent = target
                 attr_type = AttrType(qname=inner.qname, forward=True)
                 target.inner.append(inner)
             else:
diff --git a/xsdata/codegen/mappers/dtd.py b/xsdata/codegen/mappers/dtd.py
index 33644e0d0..016ccab1f 100644
--- a/xsdata/codegen/mappers/dtd.py
+++ b/xsdata/codegen/mappers/dtd.py
@@ -327,5 +327,5 @@ def build_enumeration(cls, target: Class, name: str, values: List[str]):
                     types=[attr_type.clone()],
                 )
             )
-
+        inner.parent = target
         target.inner.append(inner)
diff --git a/xsdata/codegen/mappers/element.py b/xsdata/codegen/mappers/element.py
index 78ad64f03..0c319477e 100644
--- a/xsdata/codegen/mappers/element.py
+++ b/xsdata/codegen/mappers/element.py
@@ -106,6 +106,7 @@ def build_elements(
 
                 if child.attributes or child.children:
                     inner = cls.build_class(child, namespace)
+                    inner.parent = target
                     attr_type = AttrType(qname=inner.qname, forward=True)
                     target.inner.append(inner)
                 else:
diff --git a/xsdata/codegen/mappers/schema.py b/xsdata/codegen/mappers/schema.py
index d5c145e30..2fc9ed23a 100644
--- a/xsdata/codegen/mappers/schema.py
+++ b/xsdata/codegen/mappers/schema.py
@@ -360,6 +360,7 @@ def build_attr_types(cls, target: Class, obj: ElementBase) -> List[AttrType]:
         location = target.location
         namespace = target.target_namespace
         for inner in cls.build_inner_classes(obj, location, namespace):
+            inner.parent = target
             target.inner.append(inner)
             types.append(AttrType(qname=inner.qname, forward=True))
 
diff --git a/xsdata/codegen/models.py b/xsdata/codegen/models.py
index 3acbd32b1..ed9351214 100644
--- a/xsdata/codegen/models.py
+++ b/xsdata/codegen/models.py
@@ -512,6 +512,7 @@ class Class(CodegenModel):
         attrs: The list of all the attr instances
         inner: The list of all the inner class instances
         ns_map: The namespace prefix-URI map
+        parent: The parent outer class
     """
 
     qname: str
@@ -535,6 +536,7 @@ class Class(CodegenModel):
     attrs: List[Attr] = field(default_factory=list)
     inner: List["Class"] = field(default_factory=list)
     ns_map: Dict = field(default_factory=dict)
+    parent: Optional["Class"] = field(default=None, compare=False)
 
     @property
     def name(self) -> str:
diff --git a/xsdata/codegen/utils.py b/xsdata/codegen/utils.py
index 5efedaedb..92d98ac0a 100644
--- a/xsdata/codegen/utils.py
+++ b/xsdata/codegen/utils.py
@@ -206,6 +206,7 @@ def copy_inner_class(cls, source: Class, target: Class, attr_type: AttrType):
             clone.module = target.module
             clone.status = Status.RAW
             attr_type.reference = clone.ref
+            clone.parent = target
             target.inner.append(clone)
 
     @classmethod
@@ -259,6 +260,7 @@ def flatten(cls, target: Class, location: str) -> Iterator[Class]:
             An iterator over all the found classes.
         """
         target.location = location
+        target.parent = None
 
         while target.inner:
             yield from cls.flatten(target.inner.pop(), location)

From 21e09ce776b3f984a688b1588db09b8cce38a434 Mon Sep 17 00:00:00 2001
From: Christodoulos Tsoulloftas <chris@komposta.net>
Date: Sat, 20 Apr 2024 17:12:16 +0300
Subject: [PATCH 2/4] feat: Use bidirectional classes navigation in filters

---
 tests/codegen/test_utils.py                   |  25 +++
 tests/formats/dataclass/test_filters.py       | 209 +++++++++---------
 xsdata/codegen/models.py                      |  10 +
 xsdata/codegen/utils.py                       |  44 +++-
 xsdata/formats/dataclass/filters.py           |  52 ++---
 .../formats/dataclass/templates/class.jinja2  |   8 +-
 6 files changed, 211 insertions(+), 137 deletions(-)

diff --git a/tests/codegen/test_utils.py b/tests/codegen/test_utils.py
index d34540a21..6dd873a66 100644
--- a/tests/codegen/test_utils.py
+++ b/tests/codegen/test_utils.py
@@ -400,3 +400,28 @@ def test_filter_types(self):
         types = [xs_any]
         actual = ClassUtils.filter_types(types)
         self.assertEqual(1, len(actual))
+
+    def test_find_nested(self):
+        a = ClassFactory.create(qname="a")
+        b = ClassFactory.create(qname="b")
+        c = ClassFactory.create(qname="c")
+
+        a.inner.append(b)
+        b.inner.append(c)
+        c.parent = b
+        b.parent = a
+
+        self.assertEqual(a, ClassUtils.find_nested(a, "a"))
+        self.assertEqual(b, ClassUtils.find_nested(a, "b"))
+        self.assertEqual(b, ClassUtils.find_nested(c, "b"))
+        self.assertEqual(a, ClassUtils.find_nested(c, "a"))
+
+        a2 = ClassFactory.create(qname="a")
+        c.inner.append(a2)
+        a2.parent = c
+
+        # Breadth-first search
+        self.assertEqual(a2, ClassUtils.find_nested(c, "a"))
+
+        with self.assertRaises(CodegenError):
+            ClassUtils.find_nested(a, "nope")
diff --git a/tests/formats/dataclass/test_filters.py b/tests/formats/dataclass/test_filters.py
index ac8e613b2..42f870826 100644
--- a/tests/formats/dataclass/test_filters.py
+++ b/tests/formats/dataclass/test_filters.py
@@ -39,6 +39,24 @@ def setUp(self) -> None:
         config = GeneratorConfig()
         self.filters = Filters(config)
 
+        obj = ClassFactory.create(qname="a")
+        obj_nested = ClassFactory.create(qname="b")
+        obj_nested_nested = ClassFactory.create(qname="c")
+        obj_nested_nested_nested = ClassFactory.create(qname="d")
+
+        obj_nested_nested_nested.parent = obj_nested_nested
+        obj_nested_nested.parent = obj_nested
+        obj_nested.parent = obj
+
+        obj.inner.append(obj_nested)
+        obj_nested.inner.append(obj_nested_nested)
+        obj_nested_nested.inner.append(obj_nested_nested_nested)
+
+        self.obj = obj
+        self.obj_nested = obj_nested
+        self.obj_nested_nested = obj_nested_nested
+        self.obj_nested_nested_nested = obj_nested_nested_nested
+
     def test_class_name(self):
         self.filters.substitutions[ObjectType.CLASS]["Abc"] = "Cba"
 
@@ -231,7 +249,7 @@ def test_field_definition(self, mock_field_default_value):
         mock_field_default_value.side_effect = [1, False]
         attr = AttrFactory.native(DataType.INT)
 
-        result = self.filters.field_definition(attr, {}, None, ["Root"])
+        result = self.filters.field_definition(self.obj, attr, None)
         expected = (
             "field(\n"
             "        default=1,\n"
@@ -243,7 +261,7 @@ def test_field_definition(self, mock_field_default_value):
         )
         self.assertEqual(expected, result)
 
-        result = self.filters.field_definition(attr, {}, None, ["Root"])
+        result = self.filters.field_definition(self.obj, attr, None)
         expected = (
             "field(\n"
             "        metadata={\n"
@@ -259,7 +277,7 @@ def test_field_definition_with_prohibited_attr(self):
         attr.restrictions.max_occurs = 0
         attr.default = "1"
 
-        result = self.filters.field_definition(attr, {}, None, ["Root"])
+        result = self.filters.field_definition(self.obj, attr, None)
         expected = (
             "field(\n"
             "        init=False,\n"
@@ -279,7 +297,7 @@ def test_field_definition_with_restriction_pattern(self, mock_field_default_valu
         pattern = '([^\\ \\? > < \\* / " ": |]{1,256})'
         str_attr.restrictions.pattern = pattern
 
-        result = self.filters.field_definition(str_attr, {}, None, ["Root"])
+        result = self.filters.field_definition(self.obj, str_attr, None)
         expected = (
             "field(\n"
             "        default=None,\n"
@@ -294,7 +312,7 @@ def test_field_definition_with_restriction_pattern(self, mock_field_default_valu
     def test_field_definition_without_metadata(self, mock_field_metadata):
         mock_field_metadata.return_value = {}
         str_attr = AttrFactory.create(types=[type_str], tag=Tag.RESTRICTION)
-        result = self.filters.field_definition(str_attr, {}, None, ["Root"])
+        result = self.filters.field_definition(self.obj, str_attr, None)
         expected = "field(\n" "        default=None\n" "    )"
         self.assertEqual(expected, result)
 
@@ -429,49 +447,48 @@ def test_field_default_value_with_multiple_types(self):
     def test_field_metadata(self):
         attr = AttrFactory.element()
         expected = {"name": "attr_B", "type": "Element"}
-        self.assertEqual(expected, self.filters.field_metadata(attr, None, ["cls"]))
-        self.assertEqual(expected, self.filters.field_metadata(attr, "foo", ["cls"]))
+        self.assertEqual(expected, self.filters.field_metadata(self.obj, attr, None))
 
     def test_field_metadata_namespace(self):
         attr = AttrFactory.element(namespace="foo")
         expected = {"name": "attr_B", "namespace": "foo", "type": "Element"}
 
-        actual = self.filters.field_metadata(attr, None, ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, None)
         self.assertEqual(expected, actual)
 
-        actual = self.filters.field_metadata(attr, "foo", ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, "foo")
         self.assertNotIn("namespace", actual)
 
         attr = AttrFactory.attribute(namespace="foo")
         expected = {"name": "attr_C", "namespace": "foo", "type": "Attribute"}
-        actual = self.filters.field_metadata(attr, None, ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, None)
         self.assertEqual(expected, actual)
 
-        actual = self.filters.field_metadata(attr, "foo", ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, "foo")
         self.assertIn("namespace", actual)
 
     def test_field_metadata_name(self):
         attr = AttrFactory.element(name="bar")
         attr.local_name = "foo"
 
-        actual = self.filters.field_metadata(attr, None, ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, None)
         self.assertEqual("foo", actual["name"])
 
         attr = AttrFactory.element(name="Foo")
         attr.local_name = "foo"
-        actual = self.filters.field_metadata(attr, None, ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, None)
         self.assertNotIn("name", actual)
 
         attr = AttrFactory.create(tag=Tag.ANY, name="bar")
         attr.local_name = "foo"
-        actual = self.filters.field_metadata(attr, None, ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, None)
         self.assertNotIn("name", actual)
 
     def test_field_metadata_wrapper(self):
         attr = AttrFactory.element(wrapper="foo")
         expected = {"name": "attr_B", "wrapper": "foo", "type": "Element"}
 
-        actual = self.filters.field_metadata(attr, None, ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, None)
         self.assertEqual(expected, actual)
 
     def test_field_metadata_restrictions(self):
@@ -482,30 +499,30 @@ def test_field_metadata_restrictions(self):
         attr.restrictions.max_inclusive = "2"
 
         expected = {"min_occurs": 1, "max_occurs": 2, "max_inclusive": 2}
-        self.assertEqual(expected, self.filters.field_metadata(attr, None, []))
+        self.assertEqual(expected, self.filters.field_metadata(self.obj, attr, None))
 
         attr.restrictions.min_occurs = 1
         attr.restrictions.max_occurs = 1
         expected = {"required": True, "max_inclusive": 2}
-        self.assertEqual(expected, self.filters.field_metadata(attr, None, []))
+        self.assertEqual(expected, self.filters.field_metadata(self.obj, attr, None))
 
         attr.restrictions.nillable = True
         expected = {"nillable": True, "max_inclusive": 2}
-        self.assertEqual(expected, self.filters.field_metadata(attr, None, []))
+        self.assertEqual(expected, self.filters.field_metadata(self.obj, attr, None))
 
         attr.default = None
         attr.restrictions.tokens = True
         expected = {"max_inclusive": 2, "nillable": True, "tokens": True}
-        self.assertEqual(expected, self.filters.field_metadata(attr, None, []))
+        self.assertEqual(expected, self.filters.field_metadata(self.obj, attr, None))
 
     def test_field_metadata_mixed(self):
         attr = AttrFactory.element(mixed=True)
         expected = {"mixed": True, "name": "attr_B", "type": "Element"}
-        self.assertEqual(expected, self.filters.field_metadata(attr, "foo", ["cls"]))
+        self.assertEqual(expected, self.filters.field_metadata(self.obj, attr, "foo"))
 
     def test_field_metadata_choices(self):
         attr = AttrFactory.create(choices=AttrFactory.list(2, tag=Tag.ELEMENT))
-        actual = self.filters.field_metadata(attr, "foo", ["cls"])
+        actual = self.filters.field_metadata(self.obj, attr, "foo")
         expected = (
             {"name": "attr_B", "type": "Type[str]"},
             {"name": "attr_C", "type": "Type[str]"},
@@ -529,7 +546,7 @@ def test_field_choices(self):
             ]
         )
 
-        actual = self.filters.field_choices(attr, "foo", ["a", "b"])
+        actual = self.filters.field_choices(self.obj, attr, "foo")
         expected = (
             {"name": "$", "type": "Type[float]", "max_exclusive": 10.0},
             {"name": "attr_B", "namespace": "bar", "type": "Type[str]"},
@@ -551,7 +568,7 @@ def test_field_choices(self):
 
         self.filters.docstring_style = DocstringStyle.ACCESSIBLE
         attr.choices[0].help = "help"
-        actual = self.filters.field_choices(attr, None, [])
+        actual = self.filters.field_choices(self.obj, attr, None)
         self.assertEqual(attr.choices[0].help, actual[0]["doc"])
         self.assertNotIn("doc", actual[1])
 
@@ -560,159 +577,138 @@ def test_field_type_with_default_value(self):
             default="1", types=AttrTypeFactory.list(1, qname="foo_bar")
         )
 
-        self.assertEqual("FooBar", self.filters.field_type(attr, []))
+        self.assertEqual("FooBar", self.filters.field_type(self.obj, attr))
 
         attr.restrictions.nillable = True
-        self.assertEqual("Optional[FooBar]", self.filters.field_type(attr, []))
+        self.assertEqual("Optional[FooBar]", self.filters.field_type(self.obj, attr))
 
         self.filters.union_type = True
-        self.assertEqual("None | FooBar", self.filters.field_type(attr, []))
+        self.assertEqual("None | FooBar", self.filters.field_type(self.obj, attr))
 
     def test_field_type_with_optional_value(self):
         attr = AttrFactory.create(types=AttrTypeFactory.list(1, qname="foo_bar"))
 
-        self.assertEqual("Optional[FooBar]", self.filters.field_type(attr, []))
+        self.assertEqual("Optional[FooBar]", self.filters.field_type(self.obj, attr))
 
         self.filters.format.kw_only = True
-        self.assertEqual("FooBar", self.filters.field_type(attr, []))
+        self.assertEqual("FooBar", self.filters.field_type(self.obj, attr))
 
         attr.restrictions.min_occurs = 0
-        self.assertEqual("Optional[FooBar]", self.filters.field_type(attr, []))
+        self.assertEqual("Optional[FooBar]", self.filters.field_type(self.obj, attr))
 
         self.filters.union_type = True
-        self.assertEqual("None | FooBar", self.filters.field_type(attr, []))
+        self.assertEqual("None | FooBar", self.filters.field_type(self.obj, attr))
 
     def test_field_type_with_circular_reference(self):
         attr = AttrFactory.create(
-            types=AttrTypeFactory.list(1, qname="foo_bar", circular=True)
+            types=AttrTypeFactory.list(1, qname="c", circular=True)
         )
 
         self.assertEqual(
-            'Optional["FooBar"]', self.filters.field_type(attr, ["Parent"])
+            'Optional["C"]',
+            self.filters.field_type(self.obj_nested_nested_nested, attr),
         )
 
     def test_field_type_with_forward_reference(self):
         attr = AttrFactory.create(
-            types=AttrTypeFactory.list(1, qname="foo_bar", forward=True)
+            types=AttrTypeFactory.list(1, qname="b", forward=True)
         )
         self.assertEqual(
-            'Optional["Parent.Inner.FooBar"]',
-            self.filters.field_type(attr, ["Parent", "Inner"]),
+            'Optional["A.B"]',
+            self.filters.field_type(self.obj_nested_nested, attr),
         )
 
         self.filters.postponed_annotations = True
         self.filters.union_type = True
         self.assertEqual(
-            "None | Parent.Inner.FooBar",
-            self.filters.field_type(attr, ["Parent", "Inner"]),
-        )
-
-    def test_field_type_with_forward_and_circular_reference(self):
-        attr = AttrFactory.create(
-            types=AttrTypeFactory.list(1, qname="foo_bar", forward=True, circular=True)
-        )
-
-        self.assertEqual(
-            'Optional["Parent.Inner"]',
-            self.filters.field_type(attr, ["Parent", "Inner"]),
+            "None | A.B", self.filters.field_type(self.obj_nested_nested, attr)
         )
 
     def test_field_type_with_array_type(self):
         attr = AttrFactory.create(
-            types=AttrTypeFactory.list(1, qname="foo_bar", forward=True)
+            types=AttrTypeFactory.list(1, qname="c", forward=True)
         )
         attr.restrictions.max_occurs = 2
         self.assertEqual(
-            'List["A.Parent.FooBar"]',
-            self.filters.field_type(attr, ["A", "Parent"]),
+            'List["A.B.C"]',
+            self.filters.field_type(self.obj, attr),
         )
 
         self.filters.format.frozen = True
-        self.assertEqual(
-            'Tuple["A.Parent.FooBar", ...]',
-            self.filters.field_type(attr, ["A", "Parent"]),
-        )
+        self.assertEqual('Tuple["A.B.C", ...]', self.filters.field_type(self.obj, attr))
 
         self.filters.subscriptable_types = True
-        self.assertEqual(
-            'tuple["A.Parent.FooBar", ...]',
-            self.filters.field_type(attr, ["A", "Parent"]),
-        )
+        self.assertEqual('tuple["A.B.C", ...]', self.filters.field_type(self.obj, attr))
 
         self.filters.format.frozen = False
-        self.assertEqual(
-            'list["A.Parent.FooBar"]',
-            self.filters.field_type(attr, ["A", "Parent"]),
-        )
+        self.assertEqual('list["A.B.C"]', self.filters.field_type(self.obj, attr))
 
     def test_field_type_with_token_attr(self):
         attr = AttrFactory.create(
             types=AttrTypeFactory.list(1, qname="foo_bar"),
             restrictions=Restrictions(tokens=True),
         )
-        self.assertEqual("List[FooBar]", self.filters.field_type(attr, []))
+        self.assertEqual("List[FooBar]", self.filters.field_type(self.obj, attr))
 
         attr.restrictions.max_occurs = 2
-        self.assertEqual("List[List[FooBar]]", self.filters.field_type(attr, []))
+        self.assertEqual("List[List[FooBar]]", self.filters.field_type(self.obj, attr))
 
         attr.restrictions.max_occurs = 1
         self.filters.format.frozen = True
-        self.assertEqual("Tuple[FooBar, ...]", self.filters.field_type(attr, []))
+        self.assertEqual("Tuple[FooBar, ...]", self.filters.field_type(self.obj, attr))
 
         attr.restrictions.max_occurs = 2
         self.assertEqual(
-            "Tuple[Tuple[FooBar, ...], ...]", self.filters.field_type(attr, [])
+            "Tuple[Tuple[FooBar, ...], ...]", self.filters.field_type(self.obj, attr)
         )
 
         self.filters.subscriptable_types = True
         self.assertEqual(
-            "tuple[tuple[FooBar, ...], ...]", self.filters.field_type(attr, [])
+            "tuple[tuple[FooBar, ...], ...]", self.filters.field_type(self.obj, attr)
         )
 
     def test_field_type_with_alias(self):
         attr = AttrFactory.create(
-            types=AttrTypeFactory.list(
-                1, qname="foo_bar", forward=True, alias="Boss:Life"
-            )
+            types=AttrTypeFactory.list(1, qname="b", forward=True, alias="Boss:Life")
         )
         attr.restrictions.max_occurs = 2
         self.assertEqual(
-            'List["A.Parent.BossLife"]',
-            self.filters.field_type(attr, ["A", "Parent"]),
+            'List["A.BossLife"]',
+            self.filters.field_type(self.obj_nested_nested_nested, attr),
         )
 
     def test_field_type_with_multiple_types(self):
         attr = AttrFactory.create(
             types=[
-                AttrTypeFactory.create(qname="life", alias="Boss:Life", forward=True),
+                AttrTypeFactory.create(qname="c", alias="Boss:Life", forward=True),
                 AttrTypeFactory.native(DataType.INT),
             ]
         )
         attr.restrictions.max_occurs = 2
 
         self.assertEqual(
-            'List[Union["A.Parent.BossLife", int]]',
-            self.filters.field_type(attr, ["A", "Parent"]),
+            'List[Union["A.B.BossLife", int]]',
+            self.filters.field_type(self.obj_nested_nested_nested, attr),
         )
 
         self.filters.union_type = True
         self.assertEqual(
-            'List["A.Parent.BossLife" | int]',
-            self.filters.field_type(attr, ["A", "Parent"]),
+            'List["A.B.BossLife" | int]',
+            self.filters.field_type(self.obj_nested_nested_nested, attr),
         )
         self.filters.subscriptable_types = True
         self.assertEqual(
-            'list["A.Parent.BossLife" | int]',
-            self.filters.field_type(attr, ["A", "Parent"]),
+            'list["A.B.BossLife" | int]',
+            self.filters.field_type(self.obj_nested_nested_nested, attr),
         )
 
     def test_field_type_with_any_attribute(self):
         attr = AttrFactory.any_attribute()
 
-        self.assertEqual("Dict[str, str]", self.filters.field_type(attr, ["a", "b"]))
+        self.assertEqual("Dict[str, str]", self.filters.field_type(self.obj, attr))
 
         self.filters.subscriptable_types = True
-        self.assertEqual("dict[str, str]", self.filters.field_type(attr, ["a", "b"]))
+        self.assertEqual("dict[str, str]", self.filters.field_type(self.obj, attr))
 
     def test_field_type_with_native_type(self):
         attr = AttrFactory.create(
@@ -723,16 +719,16 @@ def test_field_type_with_native_type(self):
             ]
         )
         self.assertEqual(
-            "Optional[Union[int, str]]", self.filters.field_type(attr, ["a", "b"])
+            "Optional[Union[int, str]]", self.filters.field_type(self.obj, attr)
         )
 
         self.filters.union_type = True
-        self.assertEqual("None | int | str", self.filters.field_type(attr, ["a", "b"]))
+        self.assertEqual("None | int | str", self.filters.field_type(self.obj, attr))
 
     def test_field_type_with_prohibited_attr(self):
         attr = AttrFactory.create(restrictions=Restrictions(max_occurs=0))
 
-        self.assertEqual("Any", self.filters.field_type(attr, ["a", "b"]))
+        self.assertEqual("Any", self.filters.field_type(self.obj, attr))
 
     def test_field_type_with_compound_attr(self):
         attr = AttrFactory.create(
@@ -754,68 +750,75 @@ def test_field_type_with_compound_attr(self):
         )
 
         expected = "Optional[Union[str, int, List[Decimal]]]"
-        self.assertEqual(expected, self.filters.field_type(attr, []))
+        self.assertEqual(expected, self.filters.field_type(self.obj, attr))
 
         attr.restrictions.max_occurs = 2
         expected = "List[Union[str, int, List[Decimal]]]"
-        self.assertEqual(expected, self.filters.field_type(attr, []))
+        self.assertEqual(expected, self.filters.field_type(self.obj, attr))
 
         attr.restrictions.min_occurs = attr.restrictions.max_occurs = 1
         self.filters.format.kw_only = True
         expected = "Union[str, int, List[Decimal]]"
-        self.assertEqual(expected, self.filters.field_type(attr, []))
+        self.assertEqual(expected, self.filters.field_type(self.obj, attr))
 
     def test_choice_type(self):
         choice = AttrFactory.create(types=[AttrTypeFactory.create("foobar")])
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        target = ClassFactory.create()
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[Foobar]", actual)
 
     def test_choice_type_with_forward_reference(self):
         choice = AttrFactory.create(
             types=[AttrTypeFactory.create("foobar", forward=True)]
         )
-        actual = self.filters.choice_type(choice, ["a", "b"])
-        self.assertEqual('ForwardRef("A.B.Foobar")', actual)
+        target = ClassFactory.create(qname="foobar")
+        parent = ClassFactory.create(qname="a")
+        parent.inner.append(target)
+        target.parent = parent
+
+        actual = self.filters.choice_type(parent, choice)
+        self.assertEqual('ForwardRef("A.Foobar")', actual)
 
     def test_choice_type_with_circular_reference(self):
-        choice = AttrFactory.create(
-            types=[AttrTypeFactory.create("foobar", circular=True)]
-        )
-        actual = self.filters.choice_type(choice, ["a", "b"])
-        self.assertEqual('ForwardRef("Foobar")', actual)
+        choice = AttrFactory.create(types=[AttrTypeFactory.create("c", circular=True)])
+        actual = self.filters.choice_type(self.obj_nested_nested_nested, choice)
+        self.assertEqual('ForwardRef("C")', actual)
 
         self.filters.postponed_annotations = True
-        actual = self.filters.choice_type(choice, ["a", "b"])
-        self.assertEqual('ForwardRef("Foobar")', actual)
+        actual = self.filters.choice_type(self.obj_nested_nested_nested, choice)
+        self.assertEqual('ForwardRef("C")', actual)
 
     def test_choice_type_with_multiple_types(self):
         choice = AttrFactory.create(types=[type_str, type_bool])
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        target = ClassFactory.create()
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[Union[str, bool]]", actual)
 
         self.filters.union_type = True
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[str | bool]", actual)
 
     def test_choice_type_with_list_types_are_ignored(self):
         choice = AttrFactory.create(types=[type_str, type_bool])
         choice.restrictions.max_occurs = 200
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        target = ClassFactory.create()
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[Union[str, bool]]", actual)
 
     def test_choice_type_with_restrictions_tokens_true(self):
         choice = AttrFactory.create(types=[type_str, type_bool])
         choice.restrictions.tokens = True
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        target = ClassFactory.create()
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[List[Union[str, bool]]]", actual)
 
         self.filters.format.frozen = True
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[Tuple[Union[str, bool], ...]]", actual)
 
         self.filters.union_type = True
         self.filters.subscriptable_types = True
-        actual = self.filters.choice_type(choice, ["a", "b"])
+        actual = self.filters.choice_type(target, choice)
         self.assertEqual("Type[tuple[str | bool, ...]]", actual)
 
     def test_default_imports_with_decimal(self):
diff --git a/xsdata/codegen/models.py b/xsdata/codegen/models.py
index ed9351214..f8b28444b 100644
--- a/xsdata/codegen/models.py
+++ b/xsdata/codegen/models.py
@@ -714,6 +714,16 @@ def has_forward_ref(self) -> bool:
 
         return any(inner.has_forward_ref() for inner in self.inner)
 
+    def parent_names(self) -> List[str]:
+        """Return the outer class names."""
+        result = []
+        target = self.parent
+        while target is not None:
+            result.append(target.name)
+            target = target.parent
+
+        return list(reversed(result))
+
 
 @dataclass
 class Import:
diff --git a/xsdata/codegen/utils.py b/xsdata/codegen/utils.py
index 92d98ac0a..9452c91b9 100644
--- a/xsdata/codegen/utils.py
+++ b/xsdata/codegen/utils.py
@@ -1,5 +1,6 @@
 import sys
-from typing import Iterator, List, Optional, Set
+from collections import deque
+from typing import Deque, Iterator, List, Optional, Set
 
 from xsdata.codegen.exceptions import CodegenError
 from xsdata.codegen.models import (
@@ -495,3 +496,44 @@ def filter_types(cls, types: List[AttrType]) -> List[AttrType]:
             types.append(AttrType(qname=str(DataType.STRING), native=True))
 
         return types
+
+    @classmethod
+    def find_nested(cls, target: Class, qname: str) -> Class:
+        """Find a nested class by qname.
+
+        Breath-first search implementation, that goes
+        from the current level to bottom before looking
+        for outer classes.
+
+        Args:
+            target: The class instance to begin the search
+            qname: The qualified name of the nested class to find
+
+        Raises:
+            CodegenException: If the nested class cannot be found.
+
+        Returns:
+            The nested class instance.
+        """
+        queue: Deque[Class] = deque()
+        visited: Set[int] = set()
+
+        if target.inner:
+            queue.extend(target.inner)
+        elif target.parent:
+            queue.append(target.parent)
+
+        while len(queue) > 0:
+            item = queue.popleft()
+            visited.add(item.ref)
+            if item.qname == qname:
+                return item
+
+            for inner in item.inner:
+                if inner.ref not in visited:
+                    queue.append(inner)
+
+            if len(queue) == 0 and item.parent:
+                queue.append(item.parent)
+
+        raise CodegenError("Missing inner class", parent=target, qname=qname)
diff --git a/xsdata/formats/dataclass/filters.py b/xsdata/formats/dataclass/filters.py
index dcd869125..acaa29c7f 100644
--- a/xsdata/formats/dataclass/filters.py
+++ b/xsdata/formats/dataclass/filters.py
@@ -19,6 +19,7 @@
 from jinja2 import Environment
 
 from xsdata.codegen.models import Attr, AttrType, Class
+from xsdata.codegen.utils import ClassUtils
 from xsdata.formats.converter import converter
 from xsdata.formats.dataclass.models.elements import XmlType
 from xsdata.models.config import (
@@ -243,14 +244,14 @@ def apply_substitutions(self, name: str, obj_type: ObjectType) -> str:
 
     def field_definition(
         self,
+        obj: Class,
         attr: Attr,
-        ns_map: Dict,
         parent_namespace: Optional[str],
-        parents: List[str],
     ) -> str:
         """Return the field definition with any extra metadata."""
+        ns_map = obj.ns_map
         default_value = self.field_default_value(attr, ns_map)
-        metadata = self.field_metadata(attr, parent_namespace, parents)
+        metadata = self.field_metadata(obj, attr, parent_namespace)
 
         kwargs: Dict[str, Any] = {}
         if attr.fixed or attr.is_prohibited:
@@ -421,9 +422,9 @@ def post_meta_hook(self, obj: Class) -> Optional[str]:
 
     def field_metadata(
         self,
+        obj: Class,
         attr: Attr,
         parent_namespace: Optional[str],
-        parents: List[str],
     ) -> Dict:
         """Return a metadata dictionary for the given attribute."""
         if attr.is_prohibited:
@@ -432,7 +433,7 @@ def field_metadata(
         name = namespace = None
 
         if not attr.is_nameless and attr.local_name != self.field_name(
-            attr.name, parents[-1]
+            attr.name, obj.name
         ):
             name = attr.local_name
 
@@ -447,7 +448,7 @@ def field_metadata(
             "type": attr.xml_type,
             "namespace": namespace,
             "mixed": attr.mixed,
-            "choices": self.field_choices(attr, parent_namespace, parents),
+            "choices": self.field_choices(obj, attr, parent_namespace),
             **restrictions,
         }
 
@@ -458,9 +459,9 @@ def field_metadata(
 
     def field_choices(
         self,
+        obj: Class,
         attr: Attr,
         parent_namespace: Optional[str],
-        parents: List[str],
     ) -> Optional[Tuple]:
         """Return a tuple of field metadata if the attr has choices."""
         if not attr.choices:
@@ -477,7 +478,7 @@ def field_choices(
             metadata = {
                 "name": choice.local_name,
                 "wildcard": choice.is_wildcard,
-                "type": self.choice_type(choice, parents),
+                "type": self.choice_type(obj, choice),
                 "namespace": namespace,
             }
 
@@ -742,15 +743,15 @@ def field_default_tokens(
 
         return f"lambda: {self.format_metadata(tokens, indent=8)}"
 
-    def field_type(self, attr: Attr, parents: List[str]) -> str:
+    def field_type(self, obj: Class, attr: Attr) -> str:
         """Generate type hints for the given attr."""
         if attr.is_prohibited:
             return "Any"
 
         if attr.tag == Tag.CHOICE:
-            return self.compound_field_types(attr, parents)
+            return self.compound_field_types(obj, attr)
 
-        result = self._field_type_names(attr, parents, choice=False)
+        result = self._field_type_names(obj, attr, choice=False)
 
         iterable_fmt = self._get_iterable_format()
         if attr.is_tokens:
@@ -772,12 +773,12 @@ def field_type(self, attr: Attr, parents: List[str]) -> str:
 
         return result
 
-    def compound_field_types(self, attr: Attr, parents: List[str]) -> str:
+    def compound_field_types(self, obj: Class, attr: Attr) -> str:
         """Generate type hint for a compound field.
 
         Args:
+            obj: The parent class instance
             attr: The compound attr instance
-            parents: A list of the parent class names
 
         Returns:
             The string representation of the type hint.
@@ -785,7 +786,7 @@ def compound_field_types(self, attr: Attr, parents: List[str]) -> str:
         results = []
         iterable_fmt = self._get_iterable_format()
         for choice in attr.choices:
-            names = self._field_type_names(choice, parents, choice=False)
+            names = self._field_type_names(obj, choice, choice=False)
             if choice.is_tokens:
                 names = iterable_fmt.format(names)
             results.append(names)
@@ -800,7 +801,7 @@ def compound_field_types(self, attr: Attr, parents: List[str]) -> str:
 
         return result
 
-    def choice_type(self, choice: Attr, parents: List[str]) -> str:
+    def choice_type(self, obj: Class, choice: Attr) -> str:
         """Generate type hints for the given choice.
 
         Choices support a subset of features from normal attributes.
@@ -811,13 +812,13 @@ def choice_type(self, choice: Attr, parents: List[str]) -> str:
         is also ignored.
 
         Args:
+            obj: The parent class instance
             choice: The choice instance
-            parents: A list of the parent class names
 
         Returns:
             The string representation of the type hint.
         """
-        result = self._field_type_names(choice, parents, choice=True)
+        result = self._field_type_names(obj, choice, choice=True)
 
         if choice.is_tokens:
             iterable_fmt = self._get_iterable_format()
@@ -830,13 +831,11 @@ def choice_type(self, choice: Attr, parents: List[str]) -> str:
 
     def _field_type_names(
         self,
+        obj: Class,
         attr: Attr,
-        parents: List[str],
         choice: bool = False,
     ) -> str:
-        type_names = [
-            self._field_type_name(x, parents, choice=choice) for x in attr.types
-        ]
+        type_names = [self._field_type_name(obj, x, choice=choice) for x in attr.types]
         return self._join_type_names(type_names)
 
     def _join_type_names(self, type_names: List[str]) -> str:
@@ -850,15 +849,12 @@ def _join_type_names(self, type_names: List[str]) -> str:
         return f'Union[{", ".join(type_names)}]'
 
     def _field_type_name(
-        self, attr_type: AttrType, parents: List[str], choice: bool = False
+        self, obj: Class, attr_type: AttrType, choice: bool = False
     ) -> str:
         name = self.type_name(attr_type)
-
-        if attr_type.forward and attr_type.circular:
-            outer_str = ".".join(map(self.class_name, parents))
-            name = f'"{outer_str}"'
-        elif attr_type.forward:
-            outer_str = ".".join(map(self.class_name, parents))
+        if attr_type.forward:
+            inner = ClassUtils.find_nested(obj, attr_type.qname)
+            outer_str = ".".join(map(self.class_name, inner.parent_names()))
             name = f'"{outer_str}.{name}"'
         elif attr_type.circular:
             name = f'"{name}"'
diff --git a/xsdata/formats/dataclass/templates/class.jinja2 b/xsdata/formats/dataclass/templates/class.jinja2
index 51ba2c4a5..86249b93a 100644
--- a/xsdata/formats/dataclass/templates/class.jinja2
+++ b/xsdata/formats/dataclass/templates/class.jinja2
@@ -3,7 +3,6 @@
     {%- include "docstrings." + docstring_name + ".jinja2" -%}
 {% endset -%}
 {% set parent_namespace = obj.namespace if obj.namespace is not none else parent_namespace|default(None) -%}
-{% set parents = parents|default([obj.name]) -%}
 {% set class_name =  obj.name|class_name -%}
 {% set class_annotations =  obj | class_annotations(class_name) -%}
 {% set global_type = level == 0 and not obj.local_type -%}
@@ -42,15 +41,14 @@ class {{ class_name }}{{"({})".format(base_classes) if base_classes }}:
 {{ post_meta_output|indent(4, first=True) }}
 {%- endif -%}
 {%- for attr in obj.attrs %}
-    {%- set field_typing = attr|field_type(parents) %}
-    {%- set field_definition = attr|field_definition(obj.ns_map, parent_namespace, parents) %}
+    {%- set field_typing = obj|field_type(attr) %}
+    {%- set field_definition = obj|field_definition(attr, parent_namespace) %}
     {{ attr.name|field_name(obj.name) }}: {{ field_typing }} = {{ field_definition }}
 {%- endfor -%}
 {%- for inner in obj.inner %}
     {%- set tpl = "enum.jinja2" if inner.is_enumeration else "class.jinja2" -%}
-    {%- set inner_parents = parents + [inner.name] -%}
     {%- filter indent(4) -%}
-        {%- with obj=inner, parents=inner_parents, level=(level + 1) -%}
+        {%- with obj=inner, level=(level + 1) -%}
             {% include tpl %}
         {%- endwith -%}
     {%- endfilter -%}

From 7cacca510f23dcdb874c5c4b7f878cc30c6038c0 Mon Sep 17 00:00:00 2001
From: Christodoulos Tsoulloftas <chris@komposta.net>
Date: Sat, 20 Apr 2024 19:32:27 +0300
Subject: [PATCH 3/4] chore: Remove deprecated find_inner util method

---
 tests/codegen/test_utils.py | 14 --------------
 xsdata/codegen/container.py |  2 +-
 xsdata/codegen/utils.py     | 22 +---------------------
 3 files changed, 2 insertions(+), 36 deletions(-)

diff --git a/tests/codegen/test_utils.py b/tests/codegen/test_utils.py
index 6dd873a66..f851d7454 100644
--- a/tests/codegen/test_utils.py
+++ b/tests/codegen/test_utils.py
@@ -214,20 +214,6 @@ def test_copy_inner_class_with_missing_inner(self):
         with self.assertRaises(CodegenError):
             ClassUtils.copy_inner_class(source, target, attr_type)
 
-    def test_find_inner(self):
-        obj = ClassFactory.create(qname="{a}parent")
-        first = ClassFactory.create(qname="{a}a")
-        second = ClassFactory.create(qname="{c}c")
-        third = ClassFactory.enumeration(2, qname="{d}d")
-        obj.inner.extend((first, second, third))
-
-        with self.assertRaises(CodegenError):
-            self.assertIsNone(ClassUtils.find_inner(obj, "nope"))
-
-        self.assertEqual(first, ClassUtils.find_inner(obj, "{a}a"))
-        self.assertEqual(second, ClassUtils.find_inner(obj, "{c}c"))
-        self.assertEqual(third, ClassUtils.find_inner(obj, "{d}d"))
-
     def test_flatten(self):
         target = ClassFactory.create(
             qname="{xsdata}root", attrs=AttrFactory.list(3), inner=ClassFactory.list(2)
diff --git a/xsdata/codegen/container.py b/xsdata/codegen/container.py
index 4207fee22..ae706abc0 100644
--- a/xsdata/codegen/container.py
+++ b/xsdata/codegen/container.py
@@ -148,7 +148,7 @@ def find_inner(self, source: Class, qname: str) -> Class:
         Raises:
             CodeGenerationError: If the inner class is not found.
         """
-        inner = ClassUtils.find_inner(source, qname)
+        inner = ClassUtils.find_nested(source, qname)
         if inner.status < self.step:
             self.process_class(inner, self.step)
 
diff --git a/xsdata/codegen/utils.py b/xsdata/codegen/utils.py
index 9452c91b9..c623e6bf2 100644
--- a/xsdata/codegen/utils.py
+++ b/xsdata/codegen/utils.py
@@ -196,7 +196,7 @@ def copy_inner_class(cls, source: Class, target: Class, attr_type: AttrType):
         if not attr_type.forward:
             return
 
-        inner = ClassUtils.find_inner(source, attr_type.qname)
+        inner = ClassUtils.find_nested(source, attr_type.qname)
         if inner is target:
             attr_type.circular = True
             attr_type.reference = target.ref
@@ -210,26 +210,6 @@ def copy_inner_class(cls, source: Class, target: Class, attr_type: AttrType):
             clone.parent = target
             target.inner.append(clone)
 
-    @classmethod
-    def find_inner(cls, source: Class, qname: str) -> Class:
-        """Find an inner class in the source class by its qualified name.
-
-        Args:
-            source: The parent class instance
-            qname: The inner class qualified name
-
-        Returns:
-            The inner class instance
-
-        Raises:
-            CodeGenerationError: If no inner class matched.
-        """
-        for inner in source.inner:
-            if inner.qname == qname:
-                return inner
-
-        raise CodegenError("Missing inner class", parent=source, qname=qname)
-
     @classmethod
     def find_attr(cls, source: Class, name: str) -> Optional[Attr]:
         """Find an attr in the source class by its name.

From 00fe560b2ff26de2d2b2c71d40ac074046aa5065 Mon Sep 17 00:00:00 2001
From: Christodoulos Tsoulloftas <chris@komposta.net>
Date: Sun, 21 Apr 2024 10:38:15 +0300
Subject: [PATCH 4/4] fix: Avoid recursive error on nested group references

---
 .../handlers/test_flatten_attribute_groups.py | 84 ++++++-------------
 .../handlers/flatten_attribute_groups.py      |  5 +-
 xsdata/codegen/mixins.py                      |  4 +
 xsdata/codegen/utils.py                       |  9 +-
 4 files changed, 41 insertions(+), 61 deletions(-)

diff --git a/tests/codegen/handlers/test_flatten_attribute_groups.py b/tests/codegen/handlers/test_flatten_attribute_groups.py
index 93c46b90d..4b4b6af33 100644
--- a/tests/codegen/handlers/test_flatten_attribute_groups.py
+++ b/tests/codegen/handlers/test_flatten_attribute_groups.py
@@ -1,10 +1,7 @@
-from unittest import mock
-
 from xsdata.codegen.container import ClassContainer
 from xsdata.codegen.exceptions import CodegenError
 from xsdata.codegen.handlers import FlattenAttributeGroups
-from xsdata.codegen.models import Attr, Status
-from xsdata.codegen.utils import ClassUtils
+from xsdata.codegen.models import Status
 from xsdata.models.config import GeneratorConfig
 from xsdata.models.enums import Tag
 from xsdata.utils.testing import AttrFactory, ClassFactory, FactoryTestCase
@@ -17,65 +14,38 @@ def setUp(self):
         container = ClassContainer(config=GeneratorConfig())
         self.processor = FlattenAttributeGroups(container=container)
 
-    @mock.patch.object(Attr, "is_group", new_callable=mock.PropertyMock)
-    @mock.patch.object(FlattenAttributeGroups, "process_attribute")
-    def test_process(self, mock_process_attribute, mock_is_group):
-        mock_is_group.side_effect = [
-            True,
-            False,
-            True,
-            True,
-            False,
-            False,
+    def test_process(self):
+        group = ClassFactory.create(qname="group", tag=Tag.GROUP)
+        group.attrs = [
+            AttrFactory.reference(name="one", qname="inner_one", forward=True),
+            AttrFactory.reference(name="two", qname="inner_two", forward=True),
         ]
-        target = ClassFactory.elements(2)
-
-        self.processor.process(target)
-        self.assertEqual(6, mock_is_group.call_count)
-
-        mock_process_attribute.assert_has_calls(
-            [
-                mock.call(target, target.attrs[0]),
-                mock.call(target, target.attrs[0]),
-                mock.call(target, target.attrs[1]),
-            ]
+        inner_one = ClassFactory.create(
+            qname="inner_one",
+            attrs=[
+                AttrFactory.reference(qname="group", tag=Tag.GROUP),
+            ],
         )
-
-    @mock.patch.object(ClassUtils, "copy_group_attributes")
-    def test_process_attribute_with_group(self, mock_copy_group_attributes):
-        complex_bar = ClassFactory.create(qname="bar", tag=Tag.COMPLEX_TYPE)
-        group_bar = ClassFactory.create(qname="bar", tag=Tag.ATTRIBUTE_GROUP)
-        group_attr = AttrFactory.attribute_group(name="bar")
-        target = ClassFactory.create()
-        target.attrs.append(group_attr)
-
-        self.processor.container.add(complex_bar)
-        self.processor.container.add(group_bar)
-        self.processor.container.add(target)
-
-        self.processor.process_attribute(target, group_attr)
-        mock_copy_group_attributes.assert_called_once_with(
-            group_bar, target, group_attr
+        inner_two = inner_one.clone(qname="inner_two")
+        inner_one.parent = group
+        inner_two.parent = group
+        group.inner.extend([inner_one, inner_two])
+        target = ClassFactory.create(
+            attrs=[
+                AttrFactory.reference(qname="group", tag=Tag.GROUP),
+            ]
         )
+        self.processor.container.extend([group, target])
+        self.processor.container.process()
 
-    @mock.patch.object(ClassUtils, "copy_group_attributes")
-    def test_process_attribute_with_attribute_group(self, mock_copy_group_attributes):
-        complex_bar = ClassFactory.create(qname="bar", tag=Tag.COMPLEX_TYPE)
-        group_bar = ClassFactory.create(qname="bar", tag=Tag.ATTRIBUTE_GROUP)
-        group_attr = AttrFactory.attribute_group(name="bar")
-        target = ClassFactory.create()
-        target.attrs.append(group_attr)
-
-        self.processor.container.add(complex_bar)
-        self.processor.container.add(group_bar)
-        self.processor.container.add(target)
+        self.assertEqual(["one", "two"], [x.name for x in target.attrs])
+        self.assertEqual(["inner_one", "inner_two"], [x.name for x in target.inner])
 
-        self.processor.process_attribute(target, group_attr)
-        mock_copy_group_attributes.assert_called_once_with(
-            group_bar, target, group_attr
-        )
+        for inner in target.inner:
+            self.assertEqual(["one", "two"], [x.name for x in inner.attrs])
+            self.assertEqual(0, len(inner.inner))
 
-    def test_process_attribute_with_circular_reference(self):
+    def test_process_attribute_with_self_reference(self):
         group_attr = AttrFactory.attribute_group(name="bar")
         target = ClassFactory.create(qname="bar", tag=Tag.ATTRIBUTE_GROUP)
         target.attrs.append(group_attr)
diff --git a/xsdata/codegen/handlers/flatten_attribute_groups.py b/xsdata/codegen/handlers/flatten_attribute_groups.py
index 703aeaf22..cfbbf213e 100644
--- a/xsdata/codegen/handlers/flatten_attribute_groups.py
+++ b/xsdata/codegen/handlers/flatten_attribute_groups.py
@@ -1,6 +1,6 @@
 from xsdata.codegen.exceptions import CodegenError
 from xsdata.codegen.mixins import RelativeHandlerInterface
-from xsdata.codegen.models import Attr, Class
+from xsdata.codegen.models import Attr, Class, Status
 from xsdata.codegen.utils import ClassUtils
 
 
@@ -51,4 +51,5 @@ def process_attribute(self, target: Class, attr: Attr):
         if source is target:
             ClassUtils.remove_attribute(target, attr)
         else:
-            ClassUtils.copy_group_attributes(source, target, attr)
+            is_circular_ref = source.status == Status.UNGROUPING
+            ClassUtils.copy_group_attributes(source, target, attr, is_circular_ref)
diff --git a/xsdata/codegen/mixins.py b/xsdata/codegen/mixins.py
index 11dcd5ea3..3f47de3d2 100644
--- a/xsdata/codegen/mixins.py
+++ b/xsdata/codegen/mixins.py
@@ -24,6 +24,10 @@ def __init__(self, config: GeneratorConfig):
     def __iter__(self) -> Iterator[Class]:
         """Yield an iterator for the class map values."""
 
+    @abc.abstractmethod
+    def process(self):
+        """Run the processor and filter steps."""
+
     @abc.abstractmethod
     def find(self, qname: str, condition: Callable = return_true) -> Optional[Class]:
         """Find class that matches the given qualified name and condition callable.
diff --git a/xsdata/codegen/utils.py b/xsdata/codegen/utils.py
index c623e6bf2..c7438a862 100644
--- a/xsdata/codegen/utils.py
+++ b/xsdata/codegen/utils.py
@@ -115,7 +115,9 @@ def copy_attributes(cls, source: Class, target: Class, extension: Extension):
             index += 1
 
     @classmethod
-    def copy_group_attributes(cls, source: Class, target: Class, attr: Attr):
+    def copy_group_attributes(
+        cls, source: Class, target: Class, attr: Attr, skip_inner_classes: bool = False
+    ):
         """Copy the attrs of the source class to the target class.
 
         The attr represents a reference to the source class which is
@@ -125,6 +127,8 @@ def copy_group_attributes(cls, source: Class, target: Class, attr: Attr):
             source: The source class instance
             target: The target class instance
             attr: The group attr instance
+            skip_inner_classes: Whether the attr is circular reference, which
+                means we can skip copying the inner classes.
         """
         index = target.attrs.index(attr)
         target.attrs.pop(index)
@@ -134,7 +138,8 @@ def copy_group_attributes(cls, source: Class, target: Class, attr: Attr):
             target.attrs.insert(index, clone)
             index += 1
 
-            cls.copy_inner_classes(source, target, clone)
+            if not skip_inner_classes:
+                cls.copy_inner_classes(source, target, clone)
 
     @classmethod
     def copy_extensions(cls, source: Class, target: Class, extension: Extension):