improve error message when indexing into an array is used with stable api

[pritidesai]

Expected Behavior

Indexing into array is an alpha feature. Creating a pipelineRun with embedded task specifications with a param value set to an element of an array returns a clear validation failure:

validation failed: indexing into an array requires "enable-api-fields" feature gate to be "alpha" but it is "stable": 

Actual Behavior

We have an opportunity to be more specific while reporting an error. The pipelineRun status is lacking details:

               "conditions": [
                    {
                        "lastTransitionTime": "2023-02-02T18:23:44Z",
                        "message": "Tasks Completed: 1 (Failed: 1, Cancelled 0), Skipped: 0",
                        "reason": "Failed",
                        "status": "False",
                        "type": "Succeeded"
                    }
                ],

The taskRun status is ambiguous:

  "conditions": [
    {
      "lastTransitionTime": "2023-02-02T18:23:44Z",
      "message": "failed to create task run pod \"deployrun-deploy\": non-existent variable in \"#!/bin/bash\\nVALUE=$(params.environments[1])\\nEXPECTED=\\\"qa\\\"\\ndiff=$(diff <(printf \\\"%s\\\\n\\\" \\\"${VALUE[@]}\\\") <(printf \\\"%s\\\\n\\\" \\\"${EXPECTED[@]}\\\"))\\nif [[ -z \\\"$diff\\\" ]]; then\\n    echo \\\"Get expected: ${VALUE}\\\"\\n    exit 0\\nelse\\n    echo \\\"Want: ${EXPECTED} Got: ${VALUE}\\\"\\n    exit 1\\nfi\\n\": steps[1].script\nnon-existent variable in \"$(params.environments[0])\": steps[0].args[1]. Maybe invalid TaskSpec",
      "reason": "CouldntGetTask",
      "status": "False",
      "type": "Succeeded"
    }
  ],

Steps to Reproduce the Problem

1. Deploy Tekton Pipelines with the latest commit
2. Set the feature flag to stable.
3. Apply pipelineRun from the example:

kubectl apply -f https://raw.githubusercontent.com/tektoncd/pipeline/main/examples/v1beta1/pipelineruns/alpha/pipelinerun-param-array-indexing.yaml
pipeline.tekton.dev/deploy created
pipelinerun.tekton.dev/deployrun created

Check the pipelineRun and taskRun:

kubectl get pr                                                                           
NAME        SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
deployrun   False       Failed   17s         17s

kubectl get tr 
NAME               SUCCEEDED   REASON           STARTTIME   COMPLETIONTIME
deployrun-deploy   False       CouldntGetTask   82s         82s

Additional Info

• Kubernetes version:

  Output of kubectl version:

Client Version: version.Info{Major:"1", Minor:"23", GitVersion:"v1.23.14", GitCommit:"3321ffc07d2f046afdf613796f9032f4460de093", GitTreeState:"clean", BuildDate:"2022-11-09T13:40:19Z", GoVersion:"go1.17.13", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"23", GitVersion:"v1.23.0", GitCommit:"ab69524f795c42094a6630298ff53f3c3ebab7f4", GitTreeState:"clean", BuildDate:"2021-12-07T18:09:57Z", GoVersion:"go1.17.3", Compiler:"gc", Platform:"linux/amd64"}

• Tekton Pipeline version:

  Output of tkn version or kubectl get pods -n tekton-pipelines -l app=tekton-pipelines-controller -o=jsonpath='{.items[0].metadata.labels.version}'

Client version: 0.23.1
Pipeline version: devel

The error is reported while handling a pod creation issue at https://github.com/tektoncd/pipeline/blob/main/pkg/reconciler/taskrun/taskrun.go#L649.

[Yongxuanzhang]

/assign

[tekton-robot]

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