[BUG] Kustomize support broken for kustomizations using builtin transformers (ImageTagTransformer, BploUndefined error) #1203

System info:

• OS: Linux (Ubuntu 24.04, x86_64)
• kube-linter version: v0.8.3 (installed via go install golang.stackrox.io/kube-linter/cmd/kube-linter@v0.8.3, kube-linter version reports development as expected for go install builds)

Describe the bug
Linting a Kustomize directory fails with Warning: no valid objects found. when the kustomization (or one of its bases) declares a builtin plugin explicitly via the transformers: field (e.g. an ImageTagTransformer in a separate file). Running with -v reveals the underlying error:

unknown plugin loader behavior specified: ImageTagTransformer.builtin.[noGrp] BploUndefined

This suggests the embedded krusty kustomizer is constructed with PluginConfig.BpLoadingOptions left at BploUndefined instead of BploUseStaticallyLinked. Explicit transformers:/generators: entries go through kustomize's plugin loader, which validates that option, whereas the equivalent images: shorthand does not — which matches what I observe: the same image override expressed via images: works fine, while the explicit ImageTagTransformer fails. The kustomize CLI builds the same directory without any problem.

To Reproduce
Steps to reproduce the behavior:

1. Create a standard base/overlay layout (see sample below) where the base kustomization references an ImageTagTransformer via transformers:
2. Run kube-linter lint overlays/dev
3. Output: Warning: no valid objects found.
4. Run kube-linter lint -v overlays/dev to see the rendering error
5. Replace the transformers: entry with the equivalent images: shorthand in base/kustomization.yaml and re-run: linting now works

Sample YAML input

Directory layout:

.
├── base
│   ├── deployment.yaml
│   ├── image-transformer.yaml
│   └── kustomization.yaml
└── overlays
    └── dev
        └── kustomization.yaml

base/deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      containers:
        - name: demo
          image: demo-app

base/image-transformer.yaml:

apiVersion: builtin
kind: ImageTagTransformer
metadata:
  name: image-demo-patcher
imageTag:
  name: demo-app
  newTag: v1.2.3

base/kustomization.yaml (fails):

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - deployment.yaml
transformers:
  - image-transformer.yaml

Equivalent kustomization using the images: shorthand (works):

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - deployment.yaml
images:
  - name: demo-app
    newTag: v1.2.3

overlays/dev/kustomization.yaml:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - ../../base

Expected behavior
The Kustomize directory should render and lint successfully, as it does with the kustomize CLI: kustomize build overlays/dev | kube-linter lint - works fine on the same input.

Screenshots
N/A — full verbose output:

$ kube-linter lint -v --add-all-built-in ./
Warning: failed to load object from <repo>/overlays/dev: rendering failed: error processing renderer "kustomize" (*kustomize.Renderer): error rendering kustomize path <repo>/overlays/dev: failed to run kustomize for path "<repo>/overlays/dev": failed to run kustomize for path "<repo>/overlays/dev": kustomize run failed: accumulating resources: accumulation err='accumulating resources from '../../base': '<repo>/base' must resolve to a file': recursed accumulation of path '<repo>/base': unknown plugin loader behavior specified: ImageTagTransformer.builtin.[noGrp] BploUndefined
Warning: no valid objects found.

Additional context

• Introduced with the new Kustomize support from Add Kustomize Support #1045 (v0.8.0); also reproducible on v0.8.3.
• ImageTagTransformer is likely not the only affected plugin — any builtin transformer or generator declared explicitly via transformers:/generators: should hit the same loader code path.
• Without -v, the failure is completely silent apart from the generic no valid objects found warning.
• Likely fix: set types.BploUseStaticallyLinked in the krusty.Options.PluginConfig used by the kustomize renderer.