Generator ignores nullability

[xperiandri]

Description

    Service:
      type: object
      properties:
        Услуга:
          type: string
        Стоимость:
          type: number
          format: ₴
          nullable: false
        Обязательная:
          type: boolean
          nullable: false

Expected behavior

Properties of value type marked as nullable: false declared as non-nullable and has a non-nullable parameter in a constructor

Actual behavior

nullable: false is ignored

Related information

1.0.0-Beta1

[xperiandri]

@sergey-tihon, please, point me where to apply fix I will code that today

[sergey-tihon]

Sorry, I do not understand what is the issue...

Here is the property generation code for OpenApiProvider and here for SwaggerProvider.

[xperiandri]

nullable: false

[sergey-tihon]

Here is the line where we determine if the property is optional.
https://github.com/fsprojects/SwaggerProvider/blob/net5/src/SwaggerProvider.DesignTime/v3/DefinitionCompiler.fs#L202

Is easiest way to debug is to put breakpoint on this line and check how Microsoft.OpenApi.Readers passed your schema.

[Numpsy]

Could that be because the fields aren't marked as required in the schema, so the generated properties have to be optional to handle them not being present in the Json data?

[github-actions]

🤖 This is an automated response from Repo Assist.

Great discussion here. I took a look at the current code to clarify what's happening with nullable: false.

TL;DR — the current behaviour is correct per the OpenAPI spec.

In OpenAPI 3.x, required and nullable are orthogonal concerns:

	nullable: false	nullable: true
in required list	must be present; value cannot be null	must be present; value can be null
not in required list	may be absent; if present, value cannot be null	may be absent; if present, value can be null

A property that is not required can be absent from the JSON payload regardless of its nullable flag. F# Option(T) maps this precisely:

• None → property is absent from the JSON
• Some v → property is present with a non-null value

So nullable: false on a non-required property should generate Option(T), not a plain T. The nullable flag only affects whether a present value can be null, not whether the property itself must exist.

If you have a schema where the property genuinely must always be present in the JSON (i.e., it should be in the required list of the parent object), the fix is to add it to required in the schema — that's the correct OpenAPI way to express non-optional fields.

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