Create type aliases for nested elements with titles when use-title-as-name is enabled

src/datamodel_code_generator/parser/jsonschema.py

@@ -1891,7 +1891,7 @@ def parse_combined_schema(
         target_attribute_name: str,
     ) -> list[DataType]:
         """Parse combined schema (anyOf, oneOf, allOf) into a list of data types."""
-        base_object = model_dump(obj, exclude={target_attribute_name}, exclude_unset=True, by_alias=True)
+        base_object = model_dump(obj, exclude={target_attribute_name, "title"}, exclude_unset=True, by_alias=True)
         combined_schemas: list[JsonSchemaObject] = []
         refs = []
         for index, target_attribute in enumerate(getattr(obj, target_attribute_name, [])):
@@ -2636,12 +2636,14 @@ def parse_property_names(  # noqa: PLR0912
             dict_key=key_type,
         )
 
-    def _should_create_type_alias_for_title(self, item: JsonSchemaObject, name: str) -> bool:
+    def _should_create_type_alias_for_title(  # noqa: PLR0911
+        self, item: JsonSchemaObject, name: str
+    ) -> bool:
         """Check if a type alias should be created for an inline type with title.
 
         When use_title_as_name is enabled and the item has a title, certain inline types
-        (array, dict, oneOf/anyOf unions, enum as literal) should create a type alias
-        instead of being inlined.
+        (array, dict, oneOf/anyOf unions, enum as literal, primitive types) should create
+        a type alias instead of being inlined.
         """
         if not (self.use_title_as_name and item.title):
             return False
@@ -2665,11 +2667,27 @@ def _should_create_type_alias_for_title(self, item: JsonSchemaObject, name: str)
             and isinstance(item.additionalProperties, JsonSchemaObject)
         ):
             return True
-        return bool(
+        if item.patternProperties:
+            return True
+        if item.propertyNames:
+            return True
+        if (
             item.enum
             and not self.ignore_enum_constraints
             and self.should_parse_enum_as_literal(item, property_name=name)
+        ):
+            return True
+        is_primitive = (
+            item.type
+            and not item.is_array
+            and not item.is_object
+            and not item.anyOf
+            and not item.oneOf
+            and not item.allOf
+            and not item.ref
+            and not (item.enum and not self.ignore_enum_constraints)
         )
+        return bool(is_primitive)
 
     def parse_item(  # noqa: PLR0911, PLR0912, PLR0914
         self,
@@ -2763,7 +2781,11 @@ def parse_item(  # noqa: PLR0911, PLR0912, PLR0914
                 python_type_flags = self._get_python_type_flags(item)
                 dict_flags = python_type_flags or {"is_dict": True}
                 return self.data_type(
-                    data_types=[self.parse_item(name, item.additionalProperties, object_path)],
+                    data_types=[
+                        self.parse_item(
+                            name, item.additionalProperties, get_special_path("additionalProperties", object_path)
+                        )
+                    ],
                     **dict_flags,
                 )
             return self.data_type_manager.get_data_type(
@@ -2981,7 +3003,9 @@ def parse_root_type(  # noqa: PLR0912, PLR0914, PLR0915
             python_type_flags = self._get_python_type_flags(obj)
             dict_flags = python_type_flags or {"is_dict": True}
             data_type = self.data_type(
-                data_types=[self.parse_item(name, obj.additionalProperties, path)],
+                data_types=[
+                    self.parse_item(name, obj.additionalProperties, get_special_path("additionalProperties", path))
+                ],
                 **dict_flags,
             )
         elif obj.enum and not self.ignore_enum_constraints:

tests/data/expected/main/jsonschema/use_title_as_name_nested_titles.py

@@ -0,0 +1,61 @@
+# generated by datamodel-codegen:
+#   filename:  use_title_as_name_nested_titles.json
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import NotRequired, TypedDict
+
+type MyArrayItem = str
+
+
+type MyArray = list[MyArrayItem]
+
+
+type MyObjectProp = str
+
+
+type MyObject = dict[str, MyObjectProp]
+
+
+type MyOneOfBranch = str
+
+
+type MyOneOf = MyOneOfBranch | float
+
+
+type MyAnyOfBranch = bool
+
+
+type MyAnyOf = MyAnyOfBranch | int
+
+
+type MyDeepItem = int
+
+
+type MyNestedArrayItem = list[MyDeepItem]
+
+
+type MyNestedArray = list[MyNestedArrayItem]
+
+
+type MyPatternValue = str
+
+
+type MyPatternObj = dict[str, MyPatternValue]
+
+
+type MyPropValue = int
+
+
+type MyPropNamesObj = dict[str, MyPropValue]
+
+
+class Foo(TypedDict):
+    array: NotRequired[MyArray]
+    object: NotRequired[MyObject]
+    oneOf: NotRequired[MyOneOf]
+    anyOf: NotRequired[MyAnyOf]
+    nestedArray: NotRequired[MyNestedArray]
+    patternObj: NotRequired[MyPatternObj]
+    propNamesObj: NotRequired[MyPropNamesObj]

tests/data/expected/main/jsonschema/use_title_as_name_nested_titles_pydantic.py

@@ -0,0 +1,87 @@
+# generated by datamodel-codegen:
+#   filename:  use_title_as_name_nested_titles.json
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Any
+
+from pydantic import BaseModel, Field, RootModel, constr
+
+
+class Model(RootModel[Any]):
+    root: Any
+
+
+class MyArrayItem(RootModel[str]):
+    root: str = Field(..., title='MyArrayItem')
+
+
+class MyArray(RootModel[list[MyArrayItem]]):
+    root: list[MyArrayItem] = Field(..., title='MyArray')
+
+
+class MyObjectProp(RootModel[str]):
+    root: str = Field(..., title='MyObjectProp')
+
+
+class MyObject(RootModel[dict[str, MyObjectProp]]):
+    root: dict[str, MyObjectProp] = Field(..., title='MyObject')
+
+
+class MyOneOfBranch(RootModel[str]):
+    root: str = Field(..., title='MyOneOfBranch')
+
+
+class MyOneOf(RootModel[MyOneOfBranch | float]):
+    root: MyOneOfBranch | float = Field(..., title='MyOneOf')
+
+
+class MyAnyOfBranch(RootModel[bool]):
+    root: bool = Field(..., title='MyAnyOfBranch')
+
+
+class MyAnyOf(RootModel[MyAnyOfBranch | int]):
+    root: MyAnyOfBranch | int = Field(..., title='MyAnyOf')
+
+
+class MyDeepItem(RootModel[int]):
+    root: int = Field(..., title='MyDeepItem')
+
+
+class MyNestedArrayItem(RootModel[list[MyDeepItem]]):
+    root: list[MyDeepItem] = Field(..., title='MyNestedArrayItem')
+
+
+class MyNestedArray(RootModel[list[MyNestedArrayItem]]):
+    root: list[MyNestedArrayItem] = Field(..., title='MyNestedArray')
+
+
+class MyPatternValue(RootModel[str]):
+    root: str = Field(..., title='MyPatternValue')
+
+
+class MyPatternObj(RootModel[dict[constr(pattern=r'^S_'), MyPatternValue]]):
+    root: dict[constr(pattern=r'^S_'), MyPatternValue] = Field(
+        ..., title='MyPatternObj'
+    )
+
+
+class MyPropValue(RootModel[int]):
+    root: int = Field(..., title='MyPropValue')
+
+
+class MyPropNamesObj(RootModel[dict[constr(pattern=r'^[a-z]+$'), MyPropValue]]):
+    root: dict[constr(pattern=r'^[a-z]+$'), MyPropValue] = Field(
+        ..., title='MyPropNamesObj'
+    )
+
+
+class Foo(BaseModel):
+    array: MyArray | None = Field(None, title='MyArray')
+    object: MyObject | None = Field(None, title='MyObject')
+    oneOf: MyOneOf | None = Field(None, title='MyOneOf')
+    anyOf: MyAnyOf | None = Field(None, title='MyAnyOf')
+    nestedArray: MyNestedArray | None = Field(None, title='MyNestedArray')
+    patternObj: MyPatternObj | None = Field(None, title='MyPatternObj')
+    propNamesObj: MyPropNamesObj | None = Field(None, title='MyPropNamesObj')

tests/data/jsonschema/use_title_as_name_nested_titles.json

@@ -0,0 +1,83 @@
+{
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "$defs": {
+        "Foo": {
+            "type": "object",
+            "properties": {
+                "array": {
+                    "title": "MyArray",
+                    "type": "array",
+                    "items": {
+                        "title": "MyArrayItem",
+                        "type": "string"
+                    }
+                },
+                "object": {
+                    "title": "MyObject",
+                    "type": "object",
+                    "additionalProperties": {
+                        "title": "MyObjectProp",
+                        "type": "string"
+                    }
+                },
+                "oneOf": {
+                    "title": "MyOneOf",
+                    "oneOf": [
+                        {
+                            "title": "MyOneOfBranch",
+                            "type": "string"
+                        },
+                        {
+                            "type": "number"
+                        }
+                    ]
+                },
+                "anyOf": {
+                    "title": "MyAnyOf",
+                    "anyOf": [
+                        {
+                            "title": "MyAnyOfBranch",
+                            "type": "boolean"
+                        },
+                        {
+                            "type": "integer"
+                        }
+                    ]
+                },
+                "nestedArray": {
+                    "title": "MyNestedArray",
+                    "type": "array",
+                    "items": {
+                        "title": "MyNestedArrayItem",
+                        "type": "array",
+                        "items": {
+                            "title": "MyDeepItem",
+                            "type": "integer"
+                        }
+                    }
+                },
+                "patternObj": {
+                    "title": "MyPatternObj",
+                    "type": "object",
+                    "patternProperties": {
+                        "^S_": {
+                            "title": "MyPatternValue",
+                            "type": "string"
+                        }
+                    }
+                },
+                "propNamesObj": {
+                    "title": "MyPropNamesObj",
+                    "type": "object",
+                    "propertyNames": {
+                        "pattern": "^[a-z]+$"
+                    },
+                    "additionalProperties": {
+                        "title": "MyPropValue",
+                        "type": "integer"
+                    }
+                }
+            }
+        }
+    }
+}

tests/main/jsonschema/test_main_jsonschema.py

@@ -3104,6 +3104,56 @@ def test_jsonschema_use_title_as_name_inline_types_pydantic(output_file: Path) -
     )
 
 
+@BLACK_PY313_SKIP
+def test_jsonschema_use_title_as_name_nested_titles(output_file: Path) -> None:
+    """Test use-title-as-name creates type aliases for nested elements with titles.
+
+    When use_title_as_name is enabled, nested elements like array items,
+    additionalProperties values, and oneOf/anyOf branches that have their own
+    titles should also create type aliases.
+
+    Fixes: https://github.com/koxudaxi/datamodel-code-generator/issues/2887
+    """
+    run_main_and_assert(
+        input_path=JSON_SCHEMA_DATA_PATH / "use_title_as_name_nested_titles.json",
+        output_path=output_file,
+        input_file_type="jsonschema",
+        assert_func=assert_file_content,
+        expected_file="use_title_as_name_nested_titles.py",
+        extra_args=[
+            "--use-title-as-name",
+            "--output-model-type",
+            "typing.TypedDict",
+            "--target-python-version",
+            "3.13",
+            "--use-union-operator",
+            "--use-standard-collections",
+            "--skip-root-model",
+        ],
+    )
+
+
+@BLACK_PY313_SKIP
+def test_jsonschema_use_title_as_name_nested_titles_pydantic(output_file: Path) -> None:
+    """Test use-title-as-name with Pydantic v2 creates named types for nested elements."""
+    run_main_and_assert(
+        input_path=JSON_SCHEMA_DATA_PATH / "use_title_as_name_nested_titles.json",
+        output_path=output_file,
+        input_file_type="jsonschema",
+        assert_func=assert_file_content,
+        expected_file="use_title_as_name_nested_titles_pydantic.py",
+        extra_args=[
+            "--use-title-as-name",
+            "--output-model-type",
+            "pydantic_v2.BaseModel",
+            "--target-python-version",
+            "3.13",
+            "--use-union-operator",
+            "--use-standard-collections",
+        ],
+    )
+
+
 def test_main_jsonschema_has_default_value(output_file: Path) -> None:
     """Test default value handling."""
     run_main_and_assert(