feat: support ignoreDifferences in per-app configuration

[sauagarwa]

Problem

When a Validated Pattern includes an ArgoCD-managed application that contains an OpenShift BuildConfig, the build controller mutates /status and /spec/triggers after ArgoCD applies the resource. This causes the Application to show OutOfSync permanently — ArgoCD sees drift it can't reconcile.

ArgoCD's standard fix is spec.ignoreDifferences on the Application CR:

spec:
  ignoreDifferences:
    - group: build.openshift.io
      kind: BuildConfig
      jsonPointers:
        - /status
        - /spec/triggers

However, the patterns operator generates Application CRs from values-*.yaml and does not pass through ignoreDifferences from the app configuration.

Current Workaround

Patching the Application CR directly:

oc patch application my-app -n vp-gitops --type merge -p '{
  "spec": {
    "ignoreDifferences": [{
      "group": "build.openshift.io",
      "kind": "BuildConfig",
      "jsonPointers": ["/status", "/spec/triggers"]
    }]
  }
}'

This works immediately but is overwritten when the patterns operator reconciles the Application.

Proposed Solution

Support ignoreDifferences in the per-app configuration in values-*.yaml:

clusterGroup:
  applications:
    my-app:
      name: my-app
      namespace: my-namespace
      path: charts/my-chart
      ignoreDifferences:
        - group: build.openshift.io
          kind: BuildConfig
          jsonPointers:
            - /status
            - /spec/triggers

The patterns operator would include this field when generating the Application CR.

Use Case

The Secure Agent Workspace pattern includes a golden image build pipeline using OpenShift BuildConfig. The BuildConfig is ArgoCD-managed so it's created automatically on fresh installs, but the build controller's mutations cause permanent OutOfSync status.

This affects any pattern that uses BuildConfig, ImageStream, or other resources with controller-managed status fields.

[mbaldessari]

In general the applications are unrolled via the values-* files by the clustergroup-chart and they do support ignoreDifferences. For example https://github.com/validatedpatterns/layered-zero-trust/blob/main/values-hub.yaml#L228 uses it. Is this not working for you or are you talking about the app-of-apps generated by the operator?