Add multiple --input-model support with inheritance preservation (#2881)

* Add multiple --input-model support with inheritance preservation

* Fix lint and coverage issues

* Simplify code to improve branch coverage

* Extract input-model processing to separate module

* Fix PEP8 naming violations and unused parameter

* Fix lint error for multi-line import

* Add expected_output_not_contains parameter to test helper

* Achieve 100% test coverage for input_model feature

* Mark pydantic v1 coercion code with pragma no cover

* Refactor input_model tests to use expected files with assert_output

* Fix expected files for Python version compatibility

* Fix import order

* Fix PR review issues: duplicate imports, duplicate test, and duplicate union types

* Fix union type override for anyOf schemas and remove duplicate test

* Clarify test docstrings: input model type tests all output to default Pydantic BaseModel

* Remove line comments

* Add test for x-python-type with union in anyOf schema

* Remove line comments except ignore comments

* Remove SKIP_PYTHON_314 and fix Union serialization for Python 3.14

* Refactor duplicate tests using pytest.mark.parametrize

* Fix lint and type errors

* Regenerate config-types

* Fix StrictTypes import in config-types with reuse-foreign strategy

- Add _resolve_type_import_from_defs method to resolve imports from
  $defs entries with x-python-import metadata
- Handle Annotated types in _serialize_python_type_full to prevent
  invalid type serialization with FieldInfo

* Use FQN for type arguments in x-python-type serialization

Add _full_type_name helper function that generates fully qualified names
for type arguments while keeping outer types as short names. This ensures
proper import resolution for custom types like StrictTypes.

- Add _full_type_name function with Union type handling (| syntax)
- Update _serialize_python_type to use _full_type_name for type args
- Update expected test file for config_class output

* Fix pyright type error in _full_type_name

* Add unit tests for 100% patch coverage

- Add tests for _simple_type_name edge cases (NoneType, generic types)
- Add tests for _full_type_name (string annotation, ForwardRef, typing specials)
- Add tests for _serialize_python_type_full with Annotated type
- Add tests for _resolve_type_import_from_defs (found, not found, no x-python-import, exception handling)

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* Fix lint error and improve test for generic type without args

Use list.__class_getitem__(()) to create a GenericAlias with origin
but no args, avoiding the ruff UP035 auto-fix that converted typing.List to list.

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* Fix variable naming: use 'spec' for find_spec result

Renamed misleading variable from 'module' to 'spec' when storing
the result of importlib.util.find_spec(), as it returns a ModuleSpec
not a module object.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

* Add tests for _full_type_name branch coverage

- Test builtin type (module='builtins') returns short name
- Test collections.abc type returns short name

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: koxudaxi

src/datamodel_code_generator/__main__.py

@@ -30,7 +30,7 @@
     from datamodel_code_generator.types import DataTypeManager
 
 
-class GraphQLParserConfigDict(TypedDict):
+class ParserConfig(TypedDict):
     data_model_type: NotRequired[type[DataModel]]
     data_model_root_type: NotRequired[type[DataModel]]
     data_type_manager_type: NotRequired[type[DataTypeManager]]
@@ -142,5 +142,8 @@ class GraphQLParserConfigDict(TypedDict):
     read_only_write_only_model_type: NotRequired[ReadOnlyWriteOnlyModelType | None]
     field_type_collision_strategy: NotRequired[FieldTypeCollisionStrategy | None]
     target_pydantic_version: NotRequired[TargetPydanticVersion | None]
+
+
+class GraphQLParserConfigDict(ParserConfig):
     data_model_scalar_type: NotRequired[type[DataModel]]
     data_model_union_type: NotRequired[type[DataModel]]

src/datamodel_code_generator/_types/graphql_parser_config_dict.py

@@ -30,7 +30,7 @@
     from datamodel_code_generator.types import DataTypeManager
 
 
-class JSONSchemaParserConfigDict(TypedDict):
+class ParserConfig(TypedDict):
     data_model_type: NotRequired[type[DataModel]]
     data_model_root_type: NotRequired[type[DataModel]]
     data_type_manager_type: NotRequired[type[DataTypeManager]]
@@ -142,3 +142,7 @@ class JSONSchemaParserConfigDict(TypedDict):
     read_only_write_only_model_type: NotRequired[ReadOnlyWriteOnlyModelType | None]
     field_type_collision_strategy: NotRequired[FieldTypeCollisionStrategy | None]
     target_pydantic_version: NotRequired[TargetPydanticVersion | None]
+
+
+class JSONSchemaParserConfigDict(ParserConfig):
+    pass

src/datamodel_code_generator/_types/jsonschema_parser_config_dict.py

@@ -31,7 +31,7 @@
     from datamodel_code_generator.types import DataTypeManager
 
 
-class OpenAPIParserConfigDict(TypedDict):
+class ParserConfig(TypedDict):
     data_model_type: NotRequired[type[DataModel]]
     data_model_root_type: NotRequired[type[DataModel]]
     data_type_manager_type: NotRequired[type[DataTypeManager]]
@@ -143,6 +143,13 @@ class OpenAPIParserConfigDict(TypedDict):
     read_only_write_only_model_type: NotRequired[ReadOnlyWriteOnlyModelType | None]
     field_type_collision_strategy: NotRequired[FieldTypeCollisionStrategy | None]
     target_pydantic_version: NotRequired[TargetPydanticVersion | None]
+
+
+class JSONSchemaParserConfig(ParserConfig):
+    pass
+
+
+class OpenAPIParserConfigDict(JSONSchemaParserConfig):
     openapi_scopes: NotRequired[list[OpenAPIScope] | None]
     include_path_parameters: NotRequired[bool]
     use_status_code_in_response_name: NotRequired[bool]

src/datamodel_code_generator/_types/openapi_parser_config_dict.py

@@ -159,8 +159,10 @@ def start_section(self, heading: str | None) -> None:
 )
 base_options.add_argument(
     "--input-model",
+    action="append",
     help="Python import path to a Pydantic v2 model or schema dict "
     "(e.g., 'mypackage.module:ClassName' or 'mypackage.schemas:SCHEMA_DICT'). "
+    "Can be specified multiple times for related models with inheritance. "
     "For dict input, --input-file-type is required. "
     "Cannot be used with --input or --url.",
     metavar="MODULE:NAME",