Add --skip-root-model option to skip generating root model (#2572)

koxudaxi · github-actions[bot] · web-flow · commit ba757dbf5d7f · 2025-12-01T21:35:46.000+09:00
* feat: add --skip-root-model option to skip generating the root model

* docs: update command help in README

🤖 Generated by GitHub Actions

* docs: clarify help text for --skip-root-model option

---------

Co-authored-by: github-actions[bot] &lt;github-actions[bot]@users.noreply.github.com&gt;
diff --git a/README.md b/README.md
@@ -478,6 +478,7 @@ Model customization:
                         Set name of models defined inline from the parent model
   --reuse-model         Reuse models on the field when a module has the model with the same
                         content
+  --skip-root-model     Skip generating the model for the root schema element
   --target-python-version {3.9,3.10,3.11,3.12,3.13,3.14}
                         target python version
   --treat-dot-as-module
diff --git a/docs/index.md b/docs/index.md
@@ -470,6 +470,7 @@ Model customization:
                         Set name of models defined inline from the parent model
   --reuse-model         Reuse models on the field when a module has the model with the same
                         content
+  --skip-root-model     Skip generating the model for the root schema element
   --target-python-version {3.9,3.10,3.11,3.12,3.13,3.14}
                         target python version
   --treat-dot-as-module
diff --git a/src/datamodel_code_generator/__init__.py b/src/datamodel_code_generator/__init__.py
@@ -337,6 +337,7 @@ def generate(  # noqa: PLR0912, PLR0913, PLR0914, PLR0915
     use_double_quotes: bool = False,
     use_union_operator: bool = False,
     collapse_root_models: bool = False,
+    skip_root_model: bool = False,
     use_type_alias: bool = False,
     special_field_name_prefix: str | None = None,
     remove_special_field_name_prefix: bool = False,
@@ -568,6 +569,7 @@ def get_header_and_first_line(csv_file: IO[str]) -> dict[str, Any]:
         use_double_quotes=use_double_quotes,
         use_union_operator=use_union_operator,
         collapse_root_models=collapse_root_models,
+        skip_root_model=skip_root_model,
         use_type_alias=use_type_alias,
         special_field_name_prefix=special_field_name_prefix,
         remove_special_field_name_prefix=remove_special_field_name_prefix,
diff --git a/src/datamodel_code_generator/__main__.py b/src/datamodel_code_generator/__main__.py
@@ -387,6 +387,7 @@ def validate_root(cls, values: dict[str, Any]) -> dict[str, Any]:  # noqa: N805
     original_field_name_delimiter: Optional[str] = None  # noqa: UP045
     use_double_quotes: bool = False
     collapse_root_models: bool = False
+    skip_root_model: bool = False
     use_type_alias: bool = False
     special_field_name_prefix: Optional[str] = None  # noqa: UP045
     remove_special_field_name_prefix: bool = False
@@ -643,6 +644,7 @@ def main(args: Sequence[str] | None = None) -> Exit:  # noqa: PLR0911, PLR0912,
             original_field_name_delimiter=config.original_field_name_delimiter,
             use_double_quotes=config.use_double_quotes,
             collapse_root_models=config.collapse_root_models,
+            skip_root_model=config.skip_root_model,
             use_type_alias=config.use_type_alias,
             use_union_operator=config.use_union_operator,
             special_field_name_prefix=config.special_field_name_prefix,
diff --git a/src/datamodel_code_generator/arguments.py b/src/datamodel_code_generator/arguments.py
@@ -154,6 +154,12 @@ def start_section(self, heading: str | None) -> None:
     default=None,
     help="Models generated with a root-type field will be merged into the models using that root-type model",
 )
+model_options.add_argument(
+    "--skip-root-model",
+    action="store_true",
+    default=None,
+    help="Skip generating the model for the root schema element",
+)
 model_options.add_argument(
     "--disable-appending-item-suffix",
     help="Disable appending `Item` suffix to model name in an array",
diff --git a/src/datamodel_code_generator/parser/base.py b/src/datamodel_code_generator/parser/base.py
@@ -434,6 +434,7 @@ def __init__(  # noqa: PLR0913, PLR0915
         use_union_operator: bool = False,
         allow_responses_without_content: bool = False,
         collapse_root_models: bool = False,
+        skip_root_model: bool = False,
         use_type_alias: bool = False,
         special_field_name_prefix: str | None = None,
         remove_special_field_name_prefix: bool = False,
@@ -569,6 +570,7 @@ def __init__(  # noqa: PLR0913, PLR0915
         self.use_double_quotes = use_double_quotes
         self.allow_responses_without_content = allow_responses_without_content
         self.collapse_root_models = collapse_root_models
+        self.skip_root_model = skip_root_model
         self.use_type_alias = use_type_alias
         self.capitalise_enum_members = capitalise_enum_members
         self.keep_model_order = keep_model_order
diff --git a/src/datamodel_code_generator/parser/graphql.py b/src/datamodel_code_generator/parser/graphql.py
@@ -155,6 +155,7 @@ def __init__(  # noqa: PLR0913
         use_union_operator: bool = False,
         allow_responses_without_content: bool = False,
         collapse_root_models: bool = False,
+        skip_root_model: bool = False,
         use_type_alias: bool = False,
         special_field_name_prefix: str | None = None,
         remove_special_field_name_prefix: bool = False,
@@ -240,6 +241,7 @@ def __init__(  # noqa: PLR0913
             use_union_operator=use_union_operator,
             allow_responses_without_content=allow_responses_without_content,
             collapse_root_models=collapse_root_models,
+            skip_root_model=skip_root_model,
             use_type_alias=use_type_alias,
             special_field_name_prefix=special_field_name_prefix,
             remove_special_field_name_prefix=remove_special_field_name_prefix,
diff --git a/src/datamodel_code_generator/parser/jsonschema.py b/src/datamodel_code_generator/parser/jsonschema.py
@@ -508,6 +508,7 @@ def __init__(  # noqa: PLR0913
         use_union_operator: bool = False,
         allow_responses_without_content: bool = False,
         collapse_root_models: bool = False,
+        skip_root_model: bool = False,
         use_type_alias: bool = False,
         special_field_name_prefix: str | None = None,
         remove_special_field_name_prefix: bool = False,
@@ -593,6 +594,7 @@ def __init__(  # noqa: PLR0913
             use_union_operator=use_union_operator,
             allow_responses_without_content=allow_responses_without_content,
             collapse_root_models=collapse_root_models,
+            skip_root_model=skip_root_model,
             use_type_alias=use_type_alias,
             special_field_name_prefix=special_field_name_prefix,
             remove_special_field_name_prefix=remove_special_field_name_prefix,
@@ -1894,7 +1896,7 @@ def _parse_file(
                     models = get_model_by_path(raw, object_paths)
                     model_name = object_paths[-1]
                     self.parse_obj(model_name, self.SCHEMA_OBJECT_TYPE.parse_obj(models), path)
-                else:
+                elif not self.skip_root_model:
                     self.parse_obj(obj_name, root_obj, path_parts or ["#"])
                 for key, model in definitions.items():
                     path = [*path_parts, _schema_path, key]
diff --git a/src/datamodel_code_generator/parser/openapi.py b/src/datamodel_code_generator/parser/openapi.py
@@ -237,6 +237,7 @@ def __init__(  # noqa: PLR0913
         use_union_operator: bool = False,
         allow_responses_without_content: bool = False,
         collapse_root_models: bool = False,
+        skip_root_model: bool = False,
         use_type_alias: bool = False,
         special_field_name_prefix: str | None = None,
         remove_special_field_name_prefix: bool = False,
@@ -322,6 +323,7 @@ def __init__(  # noqa: PLR0913
             use_union_operator=use_union_operator,
             allow_responses_without_content=allow_responses_without_content,
             collapse_root_models=collapse_root_models,
+            skip_root_model=skip_root_model,
             use_type_alias=use_type_alias,
             special_field_name_prefix=special_field_name_prefix,
             remove_special_field_name_prefix=remove_special_field_name_prefix,
diff --git a/tests/data/expected/main/skip_root_model.py b/tests/data/expected/main/skip_root_model.py
@@ -0,0 +1,14 @@
+# generated by datamodel-codegen:
+#   filename:  skip_root_model_test.json
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class Person(BaseModel):
+    name: str
+    age: Optional[int] = None
diff --git a/tests/data/jsonschema/skip_root_model_test.json b/tests/data/jsonschema/skip_root_model_test.json
@@ -0,0 +1,15 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "_Placeholder",
+  "type": "null",
+  "$defs": {
+    "Person": {
+      "type": "object",
+      "properties": {
+        "name": {"type": "string"},
+        "age": {"type": "integer"}
+      },
+      "required": ["name"]
+    }
+  }
+}
diff --git a/tests/main/test_main_general.py b/tests/main/test_main_general.py
@@ -330,3 +330,28 @@ def test_dataclass_arguments_invalid(json_str: str, match: str) -> None:
     """Test that invalid input raises ArgumentTypeError."""
     with pytest.raises(ArgumentTypeError, match=match):
         _dataclass_arguments(json_str)
+
+
+def test_skip_root_model(tmp_path: Path) -> None:
+    """Test --skip-root-model flag functionality using generate()."""
+    output_file = tmp_path / "output.py"
+    generate(
+        DATA_PATH / "jsonschema" / "skip_root_model_test.json",
+        input_file_type=InputFileType.JsonSchema,
+        output=output_file,
+        output_model_type=DataModelType.PydanticV2BaseModel,
+        skip_root_model=True,
+    )
+    assert_file_content(output_file, "skip_root_model.py")
+
+
+def test_skip_root_model_command_line(output_file: Path) -> None:
+    """Test --skip-root-model flag via command line."""
+    run_main_and_assert(
+        input_path=DATA_PATH / "jsonschema" / "skip_root_model_test.json",
+        output_path=output_file,
+        input_file_type="jsonschema",
+        assert_func=assert_file_content,
+        expected_file="skip_root_model.py",
+        extra_args=["--output-model-type", "pydantic_v2.BaseModel", "--skip-root-model"],
+    )
