Local Resolver - param substitution of default value inherited from another param

[valAndre07]

Feature request

Using local resolution, the param substitution is not well applied when using default value inherited from another param value as a fallback.

Use case

In some case, I need to use default value inherited from another param value as a fallback (overridable by a PipelineRun).

apiVersion: tekton.dev/v1
kind: Pipeline
metadata:
  name: pipeline-with-default-value-from-param
  namespace: jx
spec:
  params:
    - name: fallback-param
      type: string
      default: "fallback value"
    - name: param
      type: string
      default: $(params.fallback-param)

We also have the same use case with task.

It's working well with remote resolver when then passing param to task, but not with local resolver. The result value is the litteral $(params.fallback-param). Could this substitution be backported to local resolver ?

Thanks !

[afrittoli]

Thanks @valAndre07 for this issue. If the behaviour is not aligned between remote and local resolution, this would be a bug.
Do you have a full reproducer to share (Pipeline and Task definitions)?

[valAndre07]

@afrittoli For example, if I have this pipeline :

apiVersion: tekton.dev/v1
kind: Pipeline
metadata:
  name: test-default-param-pipeline
  namespace: jx
spec:
  description: default value inherited from another param value as a fallback
  params:
    - name: fallback-param
      description: the fallback param
      type: string
      default: "pipeline fallback value"
    - name: param
      description: the tested param
      type: string
      default: $(params.fallback-param)
  tasks:
    - name: test-default-param
      params:
        - name: param
          value: $(params.param)

and this task :

apiVersion: tekton.dev/v1
kind: Task
metadata:
  name: test-default-param-task
spec:
  params:
    - name: param
      description: the tested param
      type: string
      default: ""
  stepTemplate:
    imagePullPolicy: IfNotPresent
    env:
      - name: PARAM
        value: $(params.param)
  steps:
    - name: test-default-param
      image: alpine
      script: |
        #!/usr/bin/env sh
        set -ex

        echo "param value is $PARAM"

• When using our remote-resolver based on git, with these params in our pipelinerun :

kind: PipelineRun
spec:
  params:
    - name: param
      value: "override param value"
    - name: fallback-param
      value: "override fallback param value"

====> result : 
  param value is override param value

kind: PipelineRun
spec:
  params:
    - name: fallback-param
      value: "override fallback param value"

====> result : 
  param value is override fallback param value

  no params override

====> result : 
  param value is pipeline fallback value

• When using local resolver, with these params in our pipelinerun :

kind: PipelineRun
spec:
  params:
    - name: param
      value: "override param value"
    - name: fallback-param
      value: "override fallback param value"

====> result : 
  param value is override param value

kind: PipelineRun
spec:
  params:
    - name: fallback-param
      value: "override fallback param value"

====> result : 
  param value is $(params.fallback-param)

  no params override

====> result : 
  param value is $(params.fallback-param)

We can see that $(params.fallback-param) is litteral and not substitute

[vdemeester]

Then this sounds like a bug.
/kind bug