Improve code generation with fixes for recursion, aliasing, and modular references

.github/workflows/docs.yml

@@ -14,7 +14,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v1
       with:
-        python-version: '3.8'
+        python-version: '3.9'
         architecture: 'x64'
 
     - uses: actions/cache@v1

.github/workflows/publish.yml

@@ -20,10 +20,10 @@ jobs:
           key: ${{ runner.os }}-pip-${{ hashFiles('**/poetry.lock') }}
           restore-keys: |
             ${{ runner.os }}-pip-
-      - name: Set up Python 3.8
+      - name: Set up Python 3.9
         uses: actions/setup-python@v1
         with:
-          python-version: 3.8
+          python-version: 3.9
       - name: Build publish
         run: |
           python -m pip install poetry poetry-dynamic-versioning

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
         os: [ubuntu-latest, windows-latest, macos-latest]
 
     steps:

.gitignore

@@ -176,4 +176,6 @@ fabric.properties
 
 .idea
 
+.vscode/
+
 version.py

README.md

@@ -40,7 +40,7 @@ Options:
   --specify-tags           Use along with --generate-routers to generate specific routers from given list of tags.
   -c, --custom-visitors    PATH - A custom visitor that adds variables to the template.
   -d, --output-model-type  Specify a Pydantic base model to use (see [datamodel-code-generator](https://github.com/koxudaxi/datamodel-code-generator); default is `pydantic.BaseModel`).
-  -p, --python-version     Specify a Python version to target (default is `3.8`).
+  -p, --python-version     Specify a Python version to target (default is `3.9`).
   --install-completion     Install completion for the current shell.
   --show-completion        Show completion for the current shell, to copy it
                            or customize the installation.

fastapi_code_generator/__init__.py

@@ -0,0 +1,3 @@
+from .patches import patch_parse
+
+patch_parse()

fastapi_code_generator/__main__.py

@@ -28,7 +28,7 @@
 
 BUILTIN_VISITOR_DIR = Path(__file__).parent / "visitors"
 
-MODEL_PATH: Path = Path("models.py")
+MODEL_PATH: Path = Path("models")
 
 
 def dynamic_load_module(module_path: Path) -> Any:
@@ -63,7 +63,7 @@ def main(
         DataModelType.PydanticBaseModel.value, "--output-model-type", "-d"
     ),
     python_version: PythonVersion = typer.Option(
-        PythonVersion.PY_38.value, "--python-version", "-p"
+        PythonVersion.PY_39.value, "--python-version", "-p"
     ),
 ) -> None:
     input_name: str = input_file
@@ -72,10 +72,7 @@ def main(
     with open(input_file, encoding=encoding) as f:
         input_text = f.read()
 
-    if model_file:
-        model_path = Path(model_file).with_suffix('.py')
-    else:
-        model_path = MODEL_PATH
+    model_path = Path(model_file) if model_file else MODEL_PATH  # pragma: no cover
 
     return generate_code(
         input_name,
@@ -119,7 +116,7 @@ def generate_code(
     generate_routers: Optional[bool] = None,
     specify_tags: Optional[str] = None,
     output_model_type: DataModelType = DataModelType.PydanticBaseModel,
-    python_version: PythonVersion = PythonVersion.PY_38,
+    python_version: PythonVersion = PythonVersion.PY_39,
 ) -> None:
     if not model_path:
         model_path = MODEL_PATH
@@ -149,14 +146,16 @@ def generate_code(
 
     with chdir(output_dir):
         models = parser.parse()
-    output = output_dir / model_path
     if not models:
         # if no models (schemas), just generate an empty model file.
-        modules = {output: ("", input_name)}
+        modules = {output_dir / model_path.with_suffix('.py'): ("", input_name)}
     elif isinstance(models, str):
-        modules = {output: (models, input_name)}
+        modules = {output_dir / model_path.with_suffix('.py'): (models, input_name)}
     else:
-        raise Exception('Modular references are not supported in this version')
+        modules = {
+            output_dir / model_path / module_name[0]: (model.body, input_name)
+            for module_name, model in models.items()
+        }
 
     environment: Environment = Environment(
         loader=FileSystemLoader(

fastapi_code_generator/parser.py

@@ -2,6 +2,7 @@
 
 import pathlib
 import re
+from functools import cached_property
 from typing import (
     Any,
     Callable,
@@ -42,7 +43,6 @@
     ResponseObject,
 )
 from datamodel_code_generator.types import DataType, DataTypeManager, StrictTypes
-from datamodel_code_generator.util import cached_property
 from pydantic import BaseModel, ValidationInfo
 
 RE_APPLICATION_JSON_PATTERN: Pattern[str] = re.compile(r'^application/.*json$')
@@ -93,16 +93,43 @@
     type_hint: UsefulStr
     default: Optional[UsefulStr] = None
     default_value: Optional[UsefulStr] = None
+    field: Union[DataModelField, list[DataModelField], None] = None
     required: bool
 
     def __str__(self) -> str:
         return self.argument
 
-    @cached_property
+    @property
     def argument(self) -> str:
+        if self.field is None:
+            type_hint = self.type_hint
+        else:
+            type_hint = (
+                UsefulStr(self.field.type_hint)
+                if not isinstance(self.field, list)
+                else UsefulStr(
+                    f"Union[{', '.join(field.type_hint for field in self.field)}]"
+                )
+            )
+        if self.default is None and self.required:
+            return f'{self.name}: {type_hint}'
+        return f'{self.name}: {type_hint} = {self.default}'
+
+    @property
+    def snakecase(self) -> str:
+        if self.field is None:
+            type_hint = self.type_hint
+        else:
+            type_hint = (
+                UsefulStr(self.field.type_hint)
+                if not isinstance(self.field, list)
+                else UsefulStr(
+                    f"Union[{', '.join(field.type_hint for field in self.field)}]"
+                )
+            )
         if self.default is None and self.required:
-            return f'{self.name}: {self.type_hint}'
-        return f'{self.name}: {self.type_hint} = {self.default}'
+            return f'{stringcase.snakecase(self.name)}: {type_hint}'
+        return f'{stringcase.snakecase(self.name)}: {type_hint} = {self.default}'
 
 
 class Operation(CachedPropertyModel):
@@ -114,16 +141,39 @@
     parameters: List[Dict[str, Any]] = []
     responses: Dict[UsefulStr, Any] = {}
     deprecated: bool = False
-    imports: List[Import] = []
     security: Optional[List[Dict[str, List[str]]]] = None
     tags: Optional[List[str]] = []
-    arguments: str = ''
-    snake_case_arguments: str = ''
     request: Optional[Argument] = None
     response: str = ''
     additional_responses: Dict[Union[str, int], Dict[str, str]] = {}
     return_type: str = ''
     callbacks: Dict[UsefulStr, List["Operation"]] = {}
+    arguments_list: List[Argument] = []
+
+    @classmethod
+    def merge_arguments_with_union(cls, arguments: List[Argument]) -> List[Argument]:
+        grouped_arguments: DefaultDict[str, List[Argument]] = DefaultDict(list)
+        for argument in arguments:
+            grouped_arguments[argument.name].append(argument)
+
+        merged_arguments = []
+        for argument_list in grouped_arguments.values():
+            if len(argument_list) == 1:
+                merged_arguments.append(argument_list[0])
+            else:
+                argument = argument_list[0]
+                fields = [
+                    item
+                    for arg in argument_list
+                    if arg.field is not None
+                    for item in (
+                        arg.field if isinstance(arg.field, list) else [arg.field]
+                    )
+                    if item is not None
+                ]
+                argument.field = fields
+                merged_arguments.append(argument)
+        return merged_arguments
 
     @cached_property
     def type(self) -> UsefulStr:
@@ -132,6 +182,27 @@
         """
         return self.method
 
+    @property
+    def arguments(self) -> str:
+        sorted_arguments = Operation.merge_arguments_with_union(self.arguments_list)
+        return ", ".join(argument.argument for argument in sorted_arguments)
+
+    @property
+    def snake_case_arguments(self) -> str:
+        sorted_arguments = Operation.merge_arguments_with_union(self.arguments_list)
+        return ", ".join(argument.snakecase for argument in sorted_arguments)
+
+    @property
+    def imports(self) -> Imports:
+        imports = Imports()
+        for argument in self.arguments_list:
+            if isinstance(argument.field, list):
+                for field in argument.field:
+                    imports.append(field.data_type.import_)
+            elif argument.field:
+                imports.append(argument.field.data_type.import_)
+        return imports
+
     @cached_property
     def root_path(self) -> UsefulStr:
         paths = self.path.split("/")
@@ -153,7 +224,7 @@
         return stringcase.snakecase(name)
 
 
-@snooper_to_methods(max_variable_length=None)
+@snooper_to_methods()
 class OpenAPIParser(OpenAPIModelParser):
     def __init__(
         self,
@@ -166,7 +237,7 @@
         base_class: Optional[str] = None,
         custom_template_dir: Optional[pathlib.Path] = None,
         extra_template_data: Optional[DefaultDict[str, Dict[str, Any]]] = None,
-        target_python_version: PythonVersion = PythonVersion.PY_37,
+        target_python_version: PythonVersion = PythonVersion.PY_39,
         dump_resolve_reference_action: Optional[Callable[[Iterable[str]], str]] = None,
         validation: bool = False,
         field_constraints: bool = False,
@@ -314,6 +385,7 @@
             default=default,  # type: ignore
             default_value=schema.default,
             required=field.required,
+            field=field,
         )
 
     def get_arguments(self, snake_case: bool, path: List[str]) -> str:
@@ -347,6 +419,10 @@
                 or argument.type_hint.startswith('Optional[')
             )
 
+        # check if there are duplicate argument.name
+        argument_names = [argument.name for argument in arguments]
+        if len(argument_names) != len(set(argument_names)):
+            self.imports_for_fastapi.append(Import(from_='typing', import_="Union"))
         return arguments
 
     def parse_request_body(
@@ -466,10 +542,7 @@
         resolved_path = self.model_resolver.resolve_ref(path)
         path_name, method = path[-2:]
 
-        self._temporary_operation['arguments'] = self.get_arguments(
-            snake_case=False, path=path
-        )
-        self._temporary_operation['snake_case_arguments'] = self.get_arguments(
+        self._temporary_operation['arguments_list'] = self.get_argument_list(
             snake_case=True, path=path
         )
         main_operation = self._temporary_operation
@@ -499,11 +572,8 @@
                         self._temporary_operation = {'_parameters': []}
                         cb_path = path + ['callbacks', key, route, method]
                         super().parse_operation(cb_op, cb_path)
-                        self._temporary_operation['arguments'] = self.get_arguments(
-                            snake_case=False, path=cb_path
-                        )
-                        self._temporary_operation['snake_case_arguments'] = (
-                            self.get_arguments(snake_case=True, path=cb_path)
+                        self._temporary_operation['arguments_list'] = (
+                            self.get_argument_list(snake_case=True, path=cb_path)
                         )
 
                         callbacks[key].append(
@@ -527,13 +597,16 @@
         reference = data_type.reference
         import functools
 
-        if not (
-            reference
-            and (
-                len(reference.children) == 1
-                or functools.reduce(lambda a, b: a == b, reference.children)
-            )
-        ):
+        try:
+            if not (
+                reference
+                and (
+                    len(reference.children) == 0
+                    or functools.reduce(lambda a, b: a == b, reference.children)
+                )
+            ):
+                return data_type
+        except RecursionError:
             return data_type
         source = reference.source
         if not isinstance(source, CustomRootType):