schema.yaml

$schema: http://json-schema.org/draft-07/schema#
title: Foo
type: object
required:
- optional_new
- required
properties:
  optional_new:
    type:
    - object
    - 'null'
    additionalProperties:
      type: string
  optional_old:
    anyOf:
    - $ref: '#/definitions/StackableNodeSelector'
    - type: 'null'
  required:
    $ref: '#/definitions/StackableNodeSelector'
definitions:
  StackableNodeSelector:
    description: |-
      We can not simply use [`BTreeMap<String, String>`] in [`StackableAffinity`], as the fields needs to be [`Atomic`]. We can not mark it as [`Atomic`], as [`crate::config::fragment::FromFragment`] is already implemented for [`BTreeMap<String, String>`].

      We `#[serde(flatten)]` the contained [`BTreeMap<String, String>`], so `serde_yaml` can deserialize everything as expected. However the generated JsonSchema will be wrong, so we need to provide our custom one (see <https://github.com/stackabletech/issues/issues/554> for details).
    type: object
    additionalProperties:
      type: string