Class defaults are not honored

[bruno-f-cruz]

Consider the following schema (for readability I will also add the corresponding class defined in Pydantic)

from pydantic import BaseModel, Field
import json
from typing import Optional


class Bar(BaseModel):
    value: int = Field(default=0, validate_default=True)
    label: str = Field(default='default', validate_default=True)
    nullable: Optional[str] = Field(default=None)


class Foo(BaseModel):
    foo_label: str = Field(default='foo_default_label', validate_default=True)
    bar_w_default: Bar = Field(default=Bar(), validate_default=True)


class Container(BaseModel):
    nullable_foo: Optional[Foo] = Field(default=None)
    foo_w_defaults: Foo = Field(default=Foo(), validate_default=True)

and the corresponding json-schema:

{
    "definitions": {
        "Bar": {
            "properties": {
                "value": {
                    "default": 0,
                    "title": "Value",
                    "type": "integer"
                },
                "label": {
                    "default": "default",
                    "title": "Label",
                    "type": "string"
                },
                "nullable": {
                    "anyOf": [
                        {
                            "type": "string"
                        },
                        {
                            "type": "null"
                        }
                    ],
                    "default": null,
                    "title": "Nullable"
                }
            },
            "title": "Bar",
            "type": "object"
        },
        "Foo": {
            "properties": {
                "foo_label": {
                    "default": "foo_default_label",
                    "title": "Foo Label",
                    "type": "string"
                },
                "bar_w_default": {
                    "allOf": [
                        {
                            "$ref": "#/definitions/Bar"
                        }
                    ],
                    "default": {
                        "value": 0,
                        "label": "default",
                        "nullable": null
                    }
                }
            },
            "title": "Foo",
            "type": "object"
        }
    },
    "properties": {
        "nullable_foo": {
            "anyOf": [
                {
                    "$ref": "#/definitions/Foo"
                },
                {
                    "type": "null"
                }
            ],
            "default": null
        },
        "foo_w_defaults": {
            "allOf": [
                {
                    "$ref": "#/definitions/Foo"
                }
            ],
            "default": {
                "foo_label": "foo_default_label",
                "bar_w_default": {
                    "label": "default",
                    "nullable": null,
                    "value": 0
                }
            }
        }
    },
    "title": "Container",
    "type": "object"
}

After running the sgen application, the corresponding csharp classes do not honor the defaults of objects from the json. For instance, calling Container will initialize the corresponding properties as nullable_foo and foo_w_defaults as null instead of following the defaults. For instance, one would expect that the foo_w_defaults property follows:

            "default": {
                "foo_label": "foo_default_label",
                "bar_w_default": {
                    "label": "default",
                    "nullable": null,
                    "value": 0
                }

This probably happens because the constructors of these classes are not explicitly initializing the variables with any value and instead rely on the default value given by the compiler (null).

public partial class Container
    {
    
        private NullableFoo _nullableFoo;
    
        private Foo _fooWDefaults;
    
        public Container()
        {
        }
    ...

Using the constructor operators in Bonsai and printing it to the console returns:

Container { nullable_foo = , foo_w_defaults =  }
Foo { foo_label = foo_default_label, bar_w_default =  }
Bar { value = 0, label = default, nullable =  }