Support strict-nullable option (#328)

README.md

@@ -70,7 +70,7 @@ usage: datamodel-codegen [-h] [--input INPUT]
                          [--input-file-type {auto,openapi,jsonschema,json,yaml,dict,csv}]
                          [--output OUTPUT] [--base-class BASE_CLASS] [--field-constraints]
                          [--snake-case-field] [--strip-default-none]
-                         [--allow-population-by-field-name] [--use-default] [--force-optional]
+                         [--allow-population-by-field-name] [--use-default] [--force-optional] [--strict-nullable]
                          [--disable-timestamp] [--use-standard-collections] [--use-schema-description] [--reuse-model]
                          [--enum-field-as-literal {all,one}] [--set-default-enum-member] [--class-name CLASS_NAME]
                          [--custom-template-dir CUSTOM_TEMPLATE_DIR]
@@ -94,6 +94,7 @@ optional arguments:
                         Allow population by field name
   --use-default         Use default value even if a field is required
   --force-optional      Force optional for required fields
+  --strict-nullable     Treat default field as a non-nullable field (only OpenAPI)
   --disable-timestamp   Disable timestamp on file headers
   --use-standard-collections
                         Use standard collections for type hinting (list, dict)

datamodel_code_generator/__init__.py

@@ -193,6 +193,7 @@ def generate(
     encoding: str = 'utf-8',
     enum_field_as_literal: Optional[LiteralType] = None,
     set_default_enum_member: bool = False,
+    strict_nullable: bool = False,
 ) -> None:
     input_text: Optional[str] = None
     if input_file_type == InputFileType.Auto:
@@ -283,6 +284,7 @@ def get_header_and_first_line(csv_file: IO[str]) -> Dict[str, Any]:
         reuse_model=reuse_model,
         enum_field_as_literal=enum_field_as_literal,
         set_default_enum_member=set_default_enum_member,
+        strict_nullable=strict_nullable,
     )
 
     with chdir(output):

datamodel_code_generator/__main__.py

@@ -102,6 +102,13 @@ def sig_int_handler(_: int, __: Any) -> None:  # pragma: no cover
     default=None,
 )
 
+arg_parser.add_argument(
+    '--strict-nullable',
+    help='Treat default field as a non-nullable field (Only OpenAPI)',
+    action='store_true',
+    default=None,
+)
+
 arg_parser.add_argument(
     '--disable-timestamp',
     help='Disable timestamp on file headers',
@@ -233,6 +240,7 @@ def validate_literal_option(cls, values: Dict[str, Any]) -> Dict[str, Any]:
     encoding: str = 'utf-8'
     enum_field_as_literal: Optional[LiteralType] = None
     set_default_enum_member: bool = False
+    strict_nullable: bool = False
 
     def merge_args(self, args: Namespace) -> None:
         for field_name in self.__fields__:
@@ -347,6 +355,7 @@ def main(args: Optional[Sequence[str]] = None) -> Exit:
             encoding=config.encoding,
             enum_field_as_literal=config.enum_field_as_literal,
             set_default_enum_member=config.set_default_enum_member,
+            strict_nullable=config.strict_nullable,
         )
         return Exit.OK
     except InvalidClassNameError as e:

datamodel_code_generator/model/base.py

@@ -37,19 +37,28 @@ class DataModelFieldBase(BaseModel):
     data_type: DataType
     constraints: Any = None
     strip_default_none: bool = False
+    nullable: Optional[bool] = None
 
     @property
     def type_hint(self) -> str:
         type_hint = self.data_type.type_hint
-        if self.required:
-            return type_hint
-        if type_hint is None or type_hint == '':
+
+        if not type_hint:
             return OPTIONAL
+        elif self.nullable is not None:
+            if self.nullable:
+                return f'{OPTIONAL}[{type_hint}]'
+            return type_hint
+        elif self.required:
+            return type_hint
         return f'{OPTIONAL}[{type_hint}]'
 
     @property
     def imports(self) -> List[Import]:
-        if not self.required:
+        if self.nullable is None:
+            if not self.required:
+                return self.data_type.imports_ + [IMPORT_OPTIONAL]
+        elif self.nullable:
             return self.data_type.imports_ + [IMPORT_OPTIONAL]
         return self.data_type.imports_
 

datamodel_code_generator/model/pydantic/base_model.py

@@ -64,6 +64,8 @@ def __str__(self) -> str:
             f"{k}={repr(v)}" for k, v in data.items() if v is not None
         )
         if not field_arguments:
+            if self.nullable and self.required:
+                return 'Field(...)'  # Field() is for mypy
             return ""
 
         value_arg = "..." if self.required else repr(self.default)
@@ -126,5 +128,6 @@ def __init__(
             self.extra_template_data['config'] = Config.parse_obj(config_parameters)
 
         for field in fields:
-            if field.field:
+            field_value = field.field
+            if field_value and field_value != '...':
                 self.imports.append(IMPORT_FIELD)

datamodel_code_generator/parser/base.py

@@ -238,6 +238,7 @@ def __init__(
         encoding: str = 'utf-8',
         enum_field_as_literal: Optional[LiteralType] = None,
         set_default_enum_member: bool = False,
+        strict_nullable: bool = False,
     ):
         self.data_type_manager: DataTypeManager = data_type_manager_type(
             target_python_version, use_standard_collections
@@ -263,6 +264,7 @@ def __init__(
         self.encoding: str = encoding
         self.enum_field_as_literal: Optional[LiteralType] = enum_field_as_literal
         self.set_default_enum_member: bool = set_default_enum_member
+        self.strict_nullable: bool = strict_nullable
 
         self.current_source_path: Optional[Path] = None
 

datamodel_code_generator/parser/jsonschema.py

@@ -32,10 +32,9 @@
 from datamodel_code_generator.model.enum import Enum
 from datamodel_code_generator.parser import LiteralType
 
-from ..imports import IMPORT_LITERAL, Import
 from ..model import pydantic as pydantic_model
 from ..parser.base import Parser
-from ..reference import Reference, is_url
+from ..reference import is_url
 from ..types import DataType, DataTypeManager, Types
 
 
@@ -249,6 +248,7 @@ def __init__(
         encoding: str = 'utf-8',
         enum_field_as_literal: Optional[LiteralType] = None,
         set_default_enum_member: bool = False,
+        strict_nullable: bool = False,
     ):
         super().__init__(
             source=source,
@@ -277,6 +277,7 @@ def __init__(
             encoding=encoding,
             enum_field_as_literal=enum_field_as_literal,
             set_default_enum_member=set_default_enum_member,
+            strict_nullable=strict_nullable,
         )
 
         self.remote_object_cache: Dict[str, Dict[str, Any]] = {}
@@ -556,6 +557,7 @@ def parse_object_fields(
                     required=required,
                     alias=alias,
                     constraints=constraints,
+                    nullable=field.nullable if self.strict_nullable else None,
                 )
             )
         return fields
@@ -663,9 +665,14 @@ def parse_array_fields(
         if self.force_optional_for_required_fields:
             required: bool = False
         else:
-            required = not obj.nullable and not (
-                obj.has_default and self.apply_default_values_for_required_fields
-            )
+            if self.strict_nullable:
+                required = not (
+                    obj.has_default and self.apply_default_values_for_required_fields
+                )
+            else:
+                required = not obj.nullable and not (
+                    obj.has_default and self.apply_default_values_for_required_fields
+                )
         return self.data_model_field_type(
             data_type=self.data_type(data_types=item_obj_data_types, is_list=True,),
             example=obj.example,
@@ -675,6 +682,7 @@ def parse_array_fields(
             title=obj.title,
             required=required,
             constraints=obj.dict(),
+            nullable=obj.nullable if self.strict_nullable else None,
         )
 
     def parse_array(
@@ -713,9 +721,14 @@ def parse_root_type(
         if self.force_optional_for_required_fields:
             required: bool = False
         else:
-            required = not obj.nullable and not (
-                obj.has_default and self.apply_default_values_for_required_fields
-            )
+            if self.strict_nullable:
+                required = not (
+                    obj.has_default and self.apply_default_values_for_required_fields
+                )
+            else:
+                required = not obj.nullable and not (
+                    obj.has_default and self.apply_default_values_for_required_fields
+                )
         reference = self.model_resolver.add(path, name, loaded=True)
         self.set_title(name, obj)
         self.set_additional_properties(name, additional_properties or obj)
@@ -730,6 +743,7 @@ def parse_root_type(
                     default=obj.default,
                     required=required,
                     constraints=obj.dict() if self.field_constraints else {},
+                    nullable=obj.nullable if self.strict_nullable else None,
                 )
             ],
             custom_base_class=self.base_class,

docs/index.md

@@ -37,7 +37,7 @@ usage: datamodel-codegen [-h] [--input INPUT]
                          [--input-file-type {auto,openapi,jsonschema,json,yaml,dict,csv}]
                          [--output OUTPUT] [--base-class BASE_CLASS] [--field-constraints]
                          [--snake-case-field] [--strip-default-none]
-                         [--allow-population-by-field-name] [--use-default] [--force-optional]
+                         [--allow-population-by-field-name] [--use-default] [--force-optional] [--strict-nullable]
                          [--disable-timestamp] [--use-standard-collections] [--use-schema-description] [--reuse-model]
                          [--enum-field-as-literal {all,one}] [--set-default-enum-member] [--class-name CLASS_NAME]
                          [--custom-template-dir CUSTOM_TEMPLATE_DIR]
@@ -61,6 +61,7 @@ optional arguments:
                         Allow population by field name
   --use-default         Use default value even if a field is required
   --force-optional      Force optional for required fields
+  --strict-nullable     Treat default field as a non-nullable field (only OpenAPI)
   --disable-timestamp   Disable timestamp on file headers
   --use-standard-collections
                         Use standard collections for type hinting (list, dict)

tests/data/expected/main/main_openapi_nullable/output.py

@@ -0,0 +1,60 @@
+# generated by datamodel-codegen:
+#   filename:  nullable.yaml
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import AnyUrl, BaseModel, Field
+
+
+class Cursors(BaseModel):
+    prev: str
+    next: Optional[str] = 'last'
+    index: float
+
+
+class TopLevel(BaseModel):
+    cursors: Cursors
+
+
+class Info(BaseModel):
+    name: str
+
+
+class User(BaseModel):
+    info: Info
+
+
+class Api(BaseModel):
+    apiKey: Optional[str] = Field(
+        None, description='To be used as a dataset parameter value'
+    )
+    apiVersionNumber: Optional[str] = Field(
+        None, description='To be used as a version parameter value'
+    )
+    apiUrl: Optional[AnyUrl] = Field(
+        None, description="The URL describing the dataset's fields"
+    )
+    apiDocumentationUrl: Optional[AnyUrl] = Field(
+        None, description='A URL to the API console for each API'
+    )
+
+
+class Apis(BaseModel):
+    __root__: Optional[List[Api]] = None
+
+
+class EmailItem(BaseModel):
+    author: str
+    address: str = Field(..., description='email address')
+    description: Optional[str] = 'empty'
+
+
+class Email(BaseModel):
+    __root__: List[EmailItem]
+
+
+class Id(BaseModel):
+    __root__: int

tests/data/expected/main/main_openapi_nullable_strict_nullable/output.py

@@ -0,0 +1,58 @@
+# generated by datamodel-codegen:
+#   filename:  nullable.yaml
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import List, Optional
+
+from pydantic import AnyUrl, BaseModel, Field
+
+
+class Cursors(BaseModel):
+    prev: Optional[str] = Field(...)
+    next: str = 'last'
+    index: float
+
+
+class TopLevel(BaseModel):
+    cursors: Cursors
+
+
+class Info(BaseModel):
+    name: str
+
+
+class User(BaseModel):
+    info: Info
+
+
+class Api(BaseModel):
+    apiKey: str = Field(None, description='To be used as a dataset parameter value')
+    apiVersionNumber: str = Field(
+        None, description='To be used as a version parameter value'
+    )
+    apiUrl: Optional[AnyUrl] = Field(
+        None, description="The URL describing the dataset's fields"
+    )
+    apiDocumentationUrl: Optional[AnyUrl] = Field(
+        None, description='A URL to the API console for each API'
+    )
+
+
+class Apis(BaseModel):
+    __root__: Optional[List[Api]] = Field(...)
+
+
+class EmailItem(BaseModel):
+    author: str
+    address: str = Field(..., description='email address')
+    description: str = 'empty'
+
+
+class Email(BaseModel):
+    __root__: List[EmailItem]
+
+
+class Id(BaseModel):
+    __root__: int