Cannot pass array to spec.tasks[0].when[0].values

[jochen1234]

I am using Tekton in openshift 4.7 and want to the when clause in pipeline to have a dynamic list to switch off/on tasks. In my test both task should not run, but only the one with the hard coded list ["blue","yellow","green"] skips. Can someone guide to what to do. Thank you very much in advance.

Pipeline

---
apiVersion: tekton.dev/v1beta1
kind: Pipeline
metadata:
  name: test
spec:
  workspaces:
    - name: psb-deployment-checkout
  params:
    - name: deployments
      type: array
      description: "array of deployment to do"
  tasks:
    - name: getpodno1
      taskRef:
        name: openshift-client
      params:
        - name: SCRIPT
          value: "oc get pods"
      when:
        - input: "red"
          operator: in
          values: ["blue","yellow","green"]
      workspaces:
        - name: output
          workspace: psb-deployment-checkout
    - name: getpodno2
      taskRef:
        name: openshift-client
      params:
        - name: SCRIPT
          value: "oc get pods"
      when:
        - input: "red"
          operator: in
          values: ["$(spec.params.deployments)"]
      workspaces:
        - name: output
          workspace: psb-deployment-checkout

PipelineRun

---
apiVersion: tekton.dev/v1beta1
kind: PipelineRun
metadata:
  name: testrun
spec:
  pipelineRef:
    name: test
  serviceAccountName: default
  params:
    - name: deployments
      value:
        - "green"
        - "yellow"
        - "blue"
  workspaces:
    - name: psb-deployment-checkout
      persistentVolumeClaim:
        claimName: psb-deployment-pvc
      subPath: git-checkout

[vdemeester]

/cc @jerop @pritidesai

[pritidesai]

This is interesting and weird. So we use star operator [*] to expand the array parameter, something like:

"$(params.deployments[*])"

The way you have specified here is not even getting replaced (with extra spec):

               "whenExpressions": [
                    {
                        "input": "red",
                        "operator": "in",
                        "values": [
                            "$(spec.params.deployments)"
                        ]
                    }
                ]

And the using the start operator, fails at the validation since the $(params.deployments[*]) returns string instead of []string

values: "$(params.deployments[*])"

cannot decode incoming new object: json: cannot unmarshal string into Go struct field WhenExpression.spec.tasks.when.values of type []string

And using the start operator within square brackets values: ["$(params.deployments[*])"], fails at the validation:

variable type invalid in "$(params.deployments[*])": spec.tasks[0].when[0].values

This is a bug, we need to fix it and document the right usage.

Thanks @jochen1234 for reporting it.

[jochen1234]

Thank you, fixing it. My Questing would be, how can I use such fix. I am using Tekton in OpenShift 4.7. Cheers