Preserve x-kubernetes-preserve-unknown-fields when serializing plain YAML-loaded CRDs

[Copilot]

KubernetesObjectApi.create() could drop CRD extension fields when input came from a plain YAML object using Kubernetes wire keys (e.g. dashed keys). This caused x-kubernetes-preserve-unknown-fields to be omitted during serialization of known typed models.

• Serializer key resolution

  • Updated generated model serialization to prefer typed property names when present, and otherwise fall back to Kubernetes wire-format baseName keys.
  • This preserves fields provided as raw YAML keys (including dashed extension keys) without changing behavior for typed objects.

• Regression coverage: plain object path

  • Added a serializer test for V1CustomResourceDefinition proving that a plain object containing:
    • properties.podTemplate['x-kubernetes-preserve-unknown-fields'] = true
      remains intact after ObjectSerializer.serialize(...).

• Regression coverage: loadYaml(...) path

  • Extended YAML loader test to include x-kubernetes-preserve-unknown-fields.
  • Confirms loadYaml<V1CustomResourceDefinition>(...) maps dashed YAML key to typed field x_kubernetes_preserve_unknown_fields as expected.

const crd = loadYaml<V1CustomResourceDefinition>(yamlText);
// mapped typed field is preserved for serialization
crd.spec.versions[0].schema!.openAPIV3Schema!.properties!['podTemplate']
  .x_kubernetes_preserve_unknown_fields === true;

• Fixes KubernetesObjectApi drops x-kubernetes-preserve-unknown-fields when given a plain YAML object #2962

[linux-foundation-easycla]

• ❌ - login: @Copilot / name: copilot-swe-agent[bot]. The commit (c55f7fb, dc9edb3, eb08c49) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please visit our EasyCLA portal and chat with our support bot.

[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Copilot
Once this PR has been reviewed and has the lgtm label, please ask for approval from brendandburns. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[mstruebing]

This needs to go into the OpenAPI Generator, right?