Add flag --use-default-keep-required-non-nullable

docs/cli-reference/index.md

@@ -11,7 +11,7 @@ This documentation is auto-generated from test cases.
 | 📁 [Base Options](base-options.md) | 10 | Input/output configuration |
 | 🔧 [Typing Customization](typing-customization.md) | 29 | Type annotation and import behavior |
 | 🏷️ [Field Customization](field-customization.md) | 24 | Field naming and docstring behavior |
-| 🏗️ [Model Customization](model-customization.md) | 39 | Model generation behavior |
+| 🏗️ [Model Customization](model-customization.md) | 40 | Model generation behavior |
 | 🎨 [Template Customization](template-customization.md) | 21 | Output formatting and custom rendering |
 | 📘 [OpenAPI-only Options](openapi-only-options.md) | 7 | OpenAPI-specific features |
 | 📋 [GraphQL-only Options](graphql-only-options.md) | 1 |  |
@@ -194,6 +194,7 @@ This documentation is auto-generated from test cases.
 - [`--use-decimal-for-multiple-of`](typing-customization.md#use-decimal-for-multiple-of)
 - [`--use-default`](model-customization.md#use-default)
 - [`--use-default-factory-for-optional-nested-models`](model-customization.md#use-default-factory-for-optional-nested-models)
+- [`--use-default-keep-required-non-nullable`](model-customization.md#use-default-keep-required-non-nullable)
 - [`--use-default-kwarg`](model-customization.md#use-default-kwarg)
 - [`--use-double-quotes`](template-customization.md#use-double-quotes)
 - [`--use-enum-values-in-discriminator`](field-customization.md#use-enum-values-in-discriminator)

docs/cli-reference/model-customization.md

@@ -37,6 +37,7 @@
 | [`--union-mode`](#union-mode) | Union mode for combining anyOf/oneOf schemas (smart or left_... |
 | [`--use-default`](#use-default) | Use default values from schema in generated models. |
 | [`--use-default-factory-for-optional-nested-models`](#use-default-factory-for-optional-nested-models) | Generate default_factory for optional nested model fields. |
+| [`--use-default-keep-required-non-nullable`](#use-default-keep-required-non-nullable) | When using default, keep required field non nullable/non-opt... |
 | [`--use-default-kwarg`](#use-default-kwarg) | Use default= keyword argument instead of positional argument... |
 | [`--use-frozen-field`](#use-frozen-field) | Generate frozen (immutable) field definitions for readOnly p... |
 | [`--use-generic-base-class`](#use-generic-base-class) | Generate a shared base class with model configuration to avo... |
@@ -5292,38 +5293,142 @@ with their defaults, making them optional to provide when instantiating the mode
 
 ??? example "Examples"
 
-    **Input Schema:**
+    === "OpenAPI"
 
-    ```json
-    {
-        "$schema": "http://json-schema.org/draft-07/schema#",
-        "type": "object",
-        "title": "Use default with const",
-        "properties": {
-            "foo": {
-                "const": "foo"
+        **Input Schema:**
+
+        ```yaml
+        openapi: 3.1.0
+        info:
+          title: Data test
+          description: Data test
+        components:
+          schemas:
+            data:
+              type: object
+              required:
+              - number
+              properties:
+                number:
+                  description: Number
+                  default: 1
+                  type: integer
+                  format: int32
+                  minimum: 0
+            block:
+              type: object
+              required:
+              - data
+              properties:
+                data:
+                  $ref: '#/components/schemas/data'
+                dataOptional:
+                  $ref: '#/components/schemas/data'
+        ```
+
+        **Output:**
+
+        === "Pydantic v2"
+
+            ```python
+            # generated by datamodel-codegen:
+            #   filename:  default_factory_keep_required_non_nullable.yaml
+            #   timestamp: 2019-07-26T00:00:00+00:00
+
+            from __future__ import annotations
+
+            from pydantic import BaseModel, Field, conint
+
+
+            class Data(BaseModel):
+                number: conint(ge=0) = Field(1, description='Number')
+
+
+            class Block(BaseModel):
+                data: Data
+                dataOptional: Data | None = None
+            ```
+
+        === "dataclass"
+
+            ```python
+            # generated by datamodel-codegen:
+            #   filename:  default_factory_keep_required_non_nullable.yaml
+            #   timestamp: 2019-07-26T00:00:00+00:00
+
+            from __future__ import annotations
+
+            from dataclasses import dataclass
+
+
+            @dataclass
+            class Data:
+                number: int = 1
+
+
+            @dataclass
+            class Block:
+                data: Data
+                dataOptional: Data | None = None
+            ```
+
+        === "msgspec"
+
+            ```python
+            # generated by datamodel-codegen:
+            #   filename:  default_factory_keep_required_non_nullable.yaml
+            #   timestamp: 2019-07-26T00:00:00+00:00
+
+            from __future__ import annotations
+
+            from typing import Annotated
+
+            from msgspec import UNSET, Meta, Struct, UnsetType
+
+
+            class Data(Struct):
+                number: Annotated[int, Meta(description='Number', ge=0)] = 1
+
+
+            class Block(Struct):
+                data: Data
+                dataOptional: Data | UnsetType = UNSET
+            ```
+
+    === "JSON Schema"
+
+        **Input Schema:**
+
+        ```json
+        {
+            "$schema": "http://json-schema.org/draft-07/schema#",
+            "type": "object",
+            "title": "Use default with const",
+            "properties": {
+                "foo": {
+                    "const": "foo"
+                }
             }
         }
-    }
-    ```
+        ```
 
-    **Output:**
+        **Output:**
 
-    ```python
-    # generated by datamodel-codegen:
-    #   filename:  use_default_with_const.json
-    #   timestamp: 2019-07-26T00:00:00+00:00
-
-    from __future__ import annotations
-
-    from typing import Literal
-
-    from pydantic import BaseModel
-
-
-    class UseDefaultWithConst(BaseModel):
-        foo: Literal['foo'] = 'foo'
-    ```
+        ```python
+        # generated by datamodel-codegen:
+        #   filename:  use_default_with_const.json
+        #   timestamp: 2019-07-26T00:00:00+00:00
+        
+        from __future__ import annotations
+        
+        from typing import Literal
+        
+        from pydantic import BaseModel
+        
+        
+        class UseDefaultWithConst(BaseModel):
+            foo: Literal['foo'] = 'foo'
+        ```
 
 ---
 
@@ -5469,6 +5574,130 @@ for optional nested model fields instead of None default:
 
 ---
 
+## `--use-default-keep-required-non-nullable` {#use-default-keep-required-non-nullable}
+
+When using default, keep required field non nullable/non-optionaloptional.
+
+The `--use-default-keep-required-non-nullable` flag keeps a required field
+as non-nullable/optional:
+- Dataclasses: `field: int = 1`
+- Pydantic: `field: int = 1`
+- msgspec: `field: int = 1`
+
+**Related:** [`--use-default`](model-customization.md#use-default)
+
+!!! tip "Usage"
+
+    ```bash
+    datamodel-codegen --input schema.json --use-default --use-default-keep-required-non-nullable # (1)!
+    ```
+
+    1. :material-arrow-left: `--use-default-keep-required-non-nullable` - the option documented here
+
+??? example "Examples"
+
+    **Input Schema:**
+
+    ```yaml
+    openapi: 3.1.0
+    info:
+      title: Data test
+      description: Data test
+    components:
+      schemas:
+        data:
+          type: object
+          required:
+          - number
+          properties:
+            number:
+              description: Number
+              default: 1
+              type: integer
+              format: int32
+              minimum: 0
+        block:
+          type: object
+          required:
+          - data
+          properties:
+            data:
+              $ref: '#/components/schemas/data'
+            dataOptional:
+              $ref: '#/components/schemas/data'
+    ```
+
+    **Output:**
+
+    === "Pydantic v2"
+
+        ```python
+        # generated by datamodel-codegen:
+        #   filename:  default_factory_keep_required_non_nullable.yaml
+        #   timestamp: 2019-07-26T00:00:00+00:00
+
+        from __future__ import annotations
+
+        from pydantic import BaseModel, Field, conint
+
+
+        class Data(BaseModel):
+            number: conint(ge=0) = Field(1, description='Number')
+
+
+        class Block(BaseModel):
+            data: Data
+            dataOptional: Data | None = None
+        ```
+
+    === "dataclass"
+
+        ```python
+        # generated by datamodel-codegen:
+        #   filename:  default_factory_keep_required_non_nullable.yaml
+        #   timestamp: 2019-07-26T00:00:00+00:00
+
+        from __future__ import annotations
+
+        from dataclasses import dataclass
+
+
+        @dataclass
+        class Data:
+            number: int = 1
+
+
+        @dataclass
+        class Block:
+            data: Data
+            dataOptional: Data | None = None
+        ```
+
+    === "msgspec"
+
+        ```python
+        # generated by datamodel-codegen:
+        #   filename:  default_factory_keep_required_non_nullable.yaml
+        #   timestamp: 2019-07-26T00:00:00+00:00
+
+        from __future__ import annotations
+
+        from typing import Annotated
+
+        from msgspec import UNSET, Meta, Struct, UnsetType
+
+
+        class Data(Struct):
+            number: Annotated[int, Meta(description='Number', ge=0)] = 1
+
+
+        class Block(Struct):
+            data: Data
+            dataOptional: Data | UnsetType = UNSET
+        ```
+
+---
+
 ## `--use-default-kwarg` {#use-default-kwarg}
 
 Use default= keyword argument instead of positional argument for fields with defaults.

docs/cli-reference/quick-reference.md

@@ -127,6 +127,7 @@ datamodel-codegen [OPTIONS]
 | [`--union-mode`](model-customization.md#union-mode) | Union mode for combining anyOf/oneOf schemas (smart or left_to_right). |
 | [`--use-default`](model-customization.md#use-default) | Use default values from schema in generated models. |
 | [`--use-default-factory-for-optional-nested-models`](model-customization.md#use-default-factory-for-optional-nested-models) | Generate default_factory for optional nested model fields. |
+| [`--use-default-keep-required-non-nullable`](model-customization.md#use-default-keep-required-non-nullable) | When using default, keep required field non nullable/non-optionaloptional. |
 | [`--use-default-kwarg`](model-customization.md#use-default-kwarg) | Use default= keyword argument instead of positional argument for fields with def... |
 | [`--use-frozen-field`](model-customization.md#use-frozen-field) | Generate frozen (immutable) field definitions for readOnly properties. |
 | [`--use-generic-base-class`](model-customization.md#use-generic-base-class) | Generate a shared base class with model configuration to avoid repetition (DRY). |
@@ -334,6 +335,7 @@ All options sorted alphabetically:
 - [`--use-decimal-for-multiple-of`](typing-customization.md#use-decimal-for-multiple-of) - Generate Decimal types for fields with multipleOf constraint...
 - [`--use-default`](model-customization.md#use-default) - Use default values from schema in generated models.
 - [`--use-default-factory-for-optional-nested-models`](model-customization.md#use-default-factory-for-optional-nested-models) - Generate default_factory for optional nested model fields.
+- [`--use-default-keep-required-non-nullable`](model-customization.md#use-default-keep-required-non-nullable) - When using default, keep required field non nullable/non-opt...
 - [`--use-default-kwarg`](model-customization.md#use-default-kwarg) - Use default= keyword argument instead of positional argument...
 - [`--use-double-quotes`](template-customization.md#use-double-quotes) - Use double quotes for string literals in generated code.
 - [`--use-enum-values-in-discriminator`](field-customization.md#use-enum-values-in-discriminator) - Use enum values in discriminator mappings for union types.