Add --jsonschema-version and --openapi-version CLI options

src/datamodel_code_generator/__init__.py

@@ -43,9 +43,11 @@
     GraphQLScope,
     InputFileType,
     InputModelRefStrategy,
+    JsonSchemaVersion,
     ModuleSplitMode,
     NamingStrategy,
     OpenAPIScope,
+    OpenAPIVersion,
     ReadOnlyWriteOnlyModelType,
     ReuseScope,
     TargetPydanticVersion,
@@ -966,10 +968,12 @@ def __getattr__(name: str) -> Any:
     "InputModelRefStrategy",
     "InvalidClassNameError",
     "InvalidFileFormatError",
+    "JsonSchemaVersion",
     "LiteralType",
     "ModuleSplitMode",
     "NamingStrategy",
     "OpenAPIScope",
+    "OpenAPIVersion",
     "PythonVersion",
     "PythonVersionMin",
     "ReadOnlyWriteOnlyModelType",

src/datamodel_code_generator/__main__.py

@@ -63,9 +63,11 @@
     InputFileType,
     InputModelRefStrategy,
     InvalidClassNameError,
+    JsonSchemaVersion,
     ModuleSplitMode,
     NamingStrategy,
     OpenAPIScope,
+    OpenAPIVersion,
     ReadOnlyWriteOnlyModelType,
     ReuseScope,
     TargetPydanticVersion,
@@ -491,6 +493,8 @@ def validate_class_name_affix_scope(cls, v: str | ClassNameAffixScope | None) ->
     input_model: Optional[list[str]] = None  # noqa: UP045
     input_model_ref_strategy: Optional[InputModelRefStrategy] = None  # noqa: UP045
     input_file_type: InputFileType = InputFileType.Auto
+    jsonschema_version: JsonSchemaVersion = JsonSchemaVersion.Auto
+    openapi_version: OpenAPIVersion = OpenAPIVersion.Auto
     output_model_type: DataModelType = DataModelType.PydanticBaseModel
     output: Optional[Path] = None  # noqa: UP045
     check: bool = False
@@ -938,6 +942,8 @@ def run_generate_from_config(  # noqa: PLR0913, PLR0917
     result = generate(
         input_=input_,
         input_file_type=config.input_file_type,
+        jsonschema_version=config.jsonschema_version,
+        openapi_version=config.openapi_version,
         output=output,
         output_model_type=config.output_model_type,
         target_python_version=config.target_python_version,

src/datamodel_code_generator/_types/generate_config_dict.py

@@ -24,9 +24,11 @@
         FieldTypeCollisionStrategy,
         GraphQLScope,
         InputFileType,
+        JsonSchemaVersion,
         ModuleSplitMode,
         NamingStrategy,
         OpenAPIScope,
+        OpenAPIVersion,
         ReadOnlyWriteOnlyModelType,
         ReuseScope,
         StrictTypes,
@@ -41,6 +43,8 @@
 class GenerateConfigDict(TypedDict):
     input_filename: NotRequired[str | None]
     input_file_type: NotRequired[InputFileType]
+    jsonschema_version: NotRequired[JsonSchemaVersion]
+    openapi_version: NotRequired[OpenAPIVersion]
     output: NotRequired[Path | None]
     output_model_type: NotRequired[DataModelType]
     target_python_version: NotRequired[PythonVersion]

src/datamodel_code_generator/_types/parser_config_dicts.py

@@ -19,8 +19,10 @@
         CollapseRootModelsNameStrategy,
         DataclassArguments,
         FieldTypeCollisionStrategy,
+        JsonSchemaVersion,
         NamingStrategy,
         OpenAPIScope,
+        OpenAPIVersion,
         ReadOnlyWriteOnlyModelType,
         ReuseScope,
         StrictTypes,
@@ -45,6 +47,8 @@ class ParserConfigDict(TypedDict):
     data_model_root_type: NotRequired[type[DataModel]]
     data_type_manager_type: NotRequired[type[DataTypeManager]]
     data_model_field_type: NotRequired[type[DataModelFieldBase]]
+    jsonschema_version: NotRequired[JsonSchemaVersion]
+    openapi_version: NotRequired[OpenAPIVersion]
     base_class: NotRequired[str | None]
     base_class_map: NotRequired[dict[str, str] | None]
     additional_imports: NotRequired[list[str] | None]

src/datamodel_code_generator/arguments.py

@@ -26,9 +26,11 @@
     FieldTypeCollisionStrategy,
     InputFileType,
     InputModelRefStrategy,
+    JsonSchemaVersion,
     ModuleSplitMode,
     NamingStrategy,
     OpenAPIScope,
+    OpenAPIVersion,
     ReadOnlyWriteOnlyModelType,
     ReuseScope,
     StrictTypes,
@@ -146,6 +148,24 @@ def start_section(self, heading: str | None) -> None:
     ),
     choices=[i.value for i in InputFileType],
 )
+base_options.add_argument(
+    "--jsonschema-version",
+    help=(
+        "JSON Schema version (default: auto). "
+        "When 'auto', version is detected from $schema field. "
+        "Specify explicitly to override detection or when $schema is missing."
+    ),
+    choices=[v.value for v in JsonSchemaVersion],
+)
+base_options.add_argument(
+    "--openapi-version",
+    help=(
+        "OpenAPI version (default: auto). "
+        "When 'auto', version is detected from openapi/swagger field. "
+        "Specify explicitly to override detection."
+    ),
+    choices=[v.value for v in OpenAPIVersion],
+)
 base_options.add_argument(
     "--output",
     help="Output file (default: stdout)",

src/datamodel_code_generator/cli_options.py

@@ -52,6 +52,9 @@ class CLIOptionMeta:
     "--profile",
     "--no-color",
     "--generate-prompt",
+    # Schema version options - placeholders for future version-specific behavior
+    "--jsonschema-version",
+    "--openapi-version",
 })
 
 # Backward compatibility alias

src/datamodel_code_generator/config.py

@@ -22,9 +22,11 @@
     FieldTypeCollisionStrategy,
     GraphQLScope,
     InputFileType,
+    JsonSchemaVersion,
     ModuleSplitMode,
     NamingStrategy,
     OpenAPIScope,
+    OpenAPIVersion,
     ReadOnlyWriteOnlyModelType,
     ReuseScope,
     TargetPydanticVersion,
@@ -78,6 +80,8 @@ class Config:
 
     input_filename: str | None = None
     input_file_type: InputFileType = InputFileType.Auto
+    jsonschema_version: JsonSchemaVersion = JsonSchemaVersion.Auto
+    openapi_version: OpenAPIVersion = OpenAPIVersion.Auto
     output: Path | None = None
     output_model_type: DataModelType = DataModelType.PydanticBaseModel
     target_python_version: PythonVersion = PythonVersionMin
@@ -224,6 +228,8 @@ class Config:
     data_model_root_type: type[DataModel] = pydantic_model.CustomRootType
     data_type_manager_type: type[DataTypeManager] = pydantic_model.DataTypeManager
     data_model_field_type: type[DataModelFieldBase] = pydantic_model.DataModelField
+    jsonschema_version: JsonSchemaVersion = JsonSchemaVersion.Auto
+    openapi_version: OpenAPIVersion = OpenAPIVersion.Auto
     base_class: str | None = None
     base_class_map: dict[str, str] | None = None
     additional_imports: list[str] | None = None

src/datamodel_code_generator/enums.py

@@ -240,6 +240,33 @@ class StrictTypes(Enum):
     bool = "bool"
 
 
+class JsonSchemaVersion(Enum):
+    """JSON Schema draft versions.
+
+    Used to specify which JSON Schema draft to use for parsing and validation.
+    Different drafts have different features and semantics.
+    """
+
+    Auto = "auto"
+    Draft04 = "draft-04"
+    Draft07 = "draft-07"
+    Draft201909 = "2019-09"
+    Draft202012 = "2020-12"
+
+
+class OpenAPIVersion(Enum):
+    """OpenAPI specification versions.
+
+    Used to specify which OpenAPI version to use for parsing.
+    Different versions have different schema semantics (e.g., nullable handling).
+    """
+
+    Auto = "auto"
+    V20 = "2.0"
+    V30 = "3.0"
+    V31 = "3.1"
+
+
 __all__ = [
     "DEFAULT_SHARED_MODULE_NAME",
     "MAX_VERSION",
@@ -256,9 +283,11 @@ class StrictTypes(Enum):
     "GraphQLScope",
     "InputFileType",
     "InputModelRefStrategy",
+    "JsonSchemaVersion",
     "ModuleSplitMode",
     "NamingStrategy",
     "OpenAPIScope",
+    "OpenAPIVersion",
     "ReadOnlyWriteOnlyModelType",
     "ReuseScope",
     "StrictTypes",

src/datamodel_code_generator/parser/base.py

@@ -806,6 +806,8 @@ def __init__(  # noqa: PLR0912, PLR0915
         self.use_subclass_enum: bool = config.use_subclass_enum
         self.use_specialized_enum: bool = config.use_specialized_enum
         self.strict_nullable: bool = config.strict_nullable
+        self.jsonschema_version = config.jsonschema_version
+        self.openapi_version = config.openapi_version
         self.use_generic_container_types: bool = config.use_generic_container_types
         self.use_union_operator: bool = config.use_union_operator
         self.enable_faux_immutability: bool = config.enable_faux_immutability

src/datamodel_code_generator/parser/openapi.py

@@ -230,6 +230,7 @@ def get_data_type(self, obj: JsonSchemaObject) -> DataType:
         # https://swagger.io/docs/specification/data-models/data-types/#null
         # OpenAPI 3.1 does allow `null` in the `type` field and is equivalent to
         # a `nullable` flag on the property itself
+        # For backward compatibility, process nullable the same way for all versions
         if obj.nullable and self.strict_nullable and isinstance(obj.type, str):
             obj.type = [obj.type, "null"]
 

tests/data/expected/main/input_model/config_class.py

@@ -77,6 +77,11 @@ class DataclassArguments(TypedDict):
 ]
 
 
+JsonSchemaVersion: TypeAlias = Literal[
+    'auto', 'draft-04', 'draft-07', '2019-09', '2020-12'
+]
+
+
 LiteralType: TypeAlias = Literal['all', 'one', 'none']
 
 
@@ -93,6 +98,9 @@ class DataclassArguments(TypedDict):
 ]
 
 
+OpenAPIVersion: TypeAlias = Literal['auto', '2.0', '3.0', '3.1']
+
+
 PythonVersion: TypeAlias = Literal['3.10', '3.11', '3.12', '3.13', '3.14']
 
 
@@ -117,6 +125,8 @@ class DataclassArguments(TypedDict):
 class GenerateConfig(TypedDict):
     input_filename: NotRequired[str | None]
     input_file_type: NotRequired[InputFileType]
+    jsonschema_version: NotRequired[JsonSchemaVersion]
+    openapi_version: NotRequired[OpenAPIVersion]
     output: NotRequired[str | None]
     output_model_type: NotRequired[DataModelType]
     target_python_version: NotRequired[PythonVersion]

tests/data/expected/main/openapi/openapi_version_nullable_v31.py

@@ -0,0 +1,12 @@
+# generated by datamodel-codegen:
+#   filename:  openapi_version_nullable.yaml
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+
+class Pet(BaseModel):
+    name: str | None = None
+    age: int | None = None

tests/data/openapi/openapi_version_nullable.yaml

@@ -0,0 +1,15 @@
+openapi: "3.1.0"
+info:
+  title: Test API
+  version: "1.0.0"
+paths: {}
+components:
+  schemas:
+    Pet:
+      type: object
+      properties:
+        name:
+          type: string
+          nullable: true
+        age:
+          type: integer

tests/main/openapi/test_main_openapi.py

@@ -4869,3 +4869,22 @@ def test_main_openapi_deprecated_field(output_file: Path) -> None:
         expected_file="deprecated_field.py",
         extra_args=["--output-model-type", "pydantic_v2.BaseModel"],
     )
+
+
+@SKIP_PYDANTIC_V1
+def test_main_openapi_version_nullable_v31(output_file: Path) -> None:
+    """Test that nullable is processed correctly in OpenAPI 3.1 mode with --openapi-version."""
+    run_main_and_assert(
+        input_path=OPEN_API_DATA_PATH / "openapi_version_nullable.yaml",
+        output_path=output_file,
+        input_file_type="openapi",
+        assert_func=assert_file_content,
+        expected_file="openapi_version_nullable_v31.py",
+        extra_args=[
+            "--output-model-type",
+            "pydantic_v2.BaseModel",
+            "--strict-nullable",
+            "--openapi-version",
+            "3.1",
+        ],
+    )

tests/main/test_public_api_signature_baseline.py

@@ -22,9 +22,11 @@
     FieldTypeCollisionStrategy,
     GraphQLScope,
     InputFileType,
+    JsonSchemaVersion,
     ModuleSplitMode,
     NamingStrategy,
     OpenAPIScope,
+    OpenAPIVersion,
     ReadOnlyWriteOnlyModelType,
     ReuseScope,
     TargetPydanticVersion,
@@ -60,6 +62,8 @@ def _baseline_generate(
     config: GenerateConfig | None = None,
     input_filename: str | None = None,
     input_file_type: InputFileType = InputFileType.Auto,
+    jsonschema_version: JsonSchemaVersion = JsonSchemaVersion.Auto,
+    openapi_version: OpenAPIVersion = OpenAPIVersion.Auto,
     output: Path | None = None,
     output_model_type: DataModelType = DataModelType.PydanticBaseModel,
     target_python_version: PythonVersion = PythonVersionMin,
@@ -200,6 +204,8 @@ def __init__(
         data_model_root_type: type[DataModel] = pydantic_model.CustomRootType,
         data_type_manager_type: type[DataTypeManager] = pydantic_model.DataTypeManager,
         data_model_field_type: type[DataModelFieldBase] = pydantic_model.DataModelField,
+        jsonschema_version: JsonSchemaVersion = JsonSchemaVersion.Auto,
+        openapi_version: OpenAPIVersion = OpenAPIVersion.Auto,
         base_class: str | None = None,
         base_class_map: dict[str, str] | None = None,
         additional_imports: list[str] | None = None,