Unable to extract images if CRDs deconstruct image fields

[james-mchugh]

For charts with CRDs that deconstruct image fields, it is currently not possible to reconstruct the image using JSONPath.

For example, the nvidia gpu-operators chart includes ClusterPolicy resources with image fields:

apiVersion: nvidia.com/v1
kind: ClusterPolicy
metadata:
  name: cluster-policy
  labels:
    app.kubernetes.io/name: gpu-operator
    helm.sh/chart: gpu-operator-v26.3.2
    app.kubernetes.io/instance: release-name
    app.kubernetes.io/version: "v26.3.2"
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/component: "gpu-operator"
spec:
  hostPaths:
    rootFS: /
    driverInstallDir: /run/nvidia/driver
  operator:
    runtimeClass: nvidia
  daemonsets:
    labels:
      helm.sh/chart: gpu-operator-v26.3.2
      app.kubernetes.io/managed-by: gpu-operator
    tolerations: 
      - effect: NoSchedule
        key: nvidia.com/gpu
        operator: Exists
    priorityClassName: system-node-critical
    updateStrategy: RollingUpdate
    rollingUpdate:
      maxUnavailable: "1"
  validator:
    repository: nvcr.io/nvidia
    image: gpu-operator
    version: "v26.3.2"
    imagePullPolicy: IfNotPresent
    plugin:
      env: []
# ~~truncated~~

In this case the "validator" image is split between three fields, spec.validator.repository, spec.validator.image, and spec.validator.version.

I expected JSONPath to be able to handle this via an expression like so

crds:
  - kind: ClusterPolicy
    apiVersion: nvidia.com/v1
    imagePaths:
      - "{.spec.validator.repository}/{.spec.validator.image}:{.spec.validator.version}"

But this did not produce the expected output

$ helm package-images nvidia/gpu-operator -m airgap.yaml --dry-run                 
Processing ref "nvidia/gpu-operator"...
warning: skipping invalid image reference "/": could not parse reference: /
warning: skipping invalid image reference ":": could not parse reference: :
Discovered 5 unique image(s):
gpu-operator
nvcr.io/nvidia
nvcr.io/nvidia/gpu-operator:v26.3.2
registry.k8s.io/nfd/node-feature-discovery:v0.18.3
v26.3.2

It may be worth considering using something more flexible than JSONPath, like Go templating.