Unable to safely use array results as input parameters for other tasks

[l-qing]

Expected Behavior

I can safely apply array results as parameters to the task, just like the usual array parameters.
When I quote the results of other tasks, I cannot ensure that the arrays in their results are definitely non-empty.

This PipelineRun can be executed successfully.

apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  name: task-with-array-result
spec:
  params:
  - name: arrayVal1
    description: "description3"
    type: array
    default: []
  steps:
  - name: step1
    image: bash:latest
    args:
      - --images
      - $(params.arrayVal1[*])
    script: |
      #!/usr/bin/env bash
      for arg in "$@"; do
        echo $arg
      done
  - name: step2
    image: bash:latest
    script: |
      #!/usr/bin/env bash
      echo -n '[]' | tee $(results.resultArray.path)
      # echo -n '["a", "b"]' | tee $(results.resultArray.path)
  results:
  - name: resultArray
    description: "description4"
    type: array

---
apiVersion: tekton.dev/v1beta1
kind: PipelineRun
metadata:
  name: pipelinerun-array-result
spec:
  pipelineSpec:
    tasks:
      - name: task-1
        taskRef:
          name: task-with-array-result
        params:
          - name: arrayVal1
            value: []
      - name: task-2
        taskRef:
          name: task-with-array-result
        params:
          - name: arrayVal1
            value: $(tasks.task-1.results.resultArray)

The arrayVal1 parameter in the first task is an empty array, see if task-1 can be successfully executed.
I have specified the result of task-1 as an empty array, it cannot be used as a parameter for task-2.

Although they are both empty arrays, their behaviors are completely different. I expect them to act consistently and all be able to successfully execute.

Actual Behavior

The pipelinerun encountered an error when executing the second task.
Encountered an error.

Array Result Index 0 for Task task-1 Result resultArray is out of bound of size 0

PipelineRun YAML:

apiVersion: tekton.dev/v1beta1
kind: PipelineRun
metadata:
  creationTimestamp: "2023-11-18T11:06:31Z"
  generation: 1
  labels:
    tekton.dev/pipeline: pipelinerun-array-result
  name: pipelinerun-array-result
  namespace: devops-b
  resourceVersion: "57520529"
  uid: 143f13ad-e0a7-4558-a8b4-0bdcdf32a0f6
spec:
  pipelineSpec:
    tasks:
    - name: task-1
      params:
      - name: arrayVal1
        value: []
      taskRef:
        kind: Task
        name: task-with-array-result
    - name: task-2
      params:
      - name: arrayVal1
        value: $(tasks.task-1.results.resultArray)
      taskRef:
        kind: Task
        name: task-with-array-result
  serviceAccountName: default
  timeouts:
    pipeline: 1h0m0s
status:
  childReferences:
  - apiVersion: tekton.dev/v1
    kind: TaskRun
    name: pipelinerun-array-result-task-1
    pipelineTaskName: task-1
  completionTime: "2023-11-18T11:06:55Z"
  conditions:
  - lastTransitionTime: "2023-11-18T11:06:55Z"
    message: 'PipelineRun devops-b/pipelinerun-array-result can''t be Run; couldn''t
      resolve all references: Array Result Index 0 for Task task-1 Result resultArray
      is out of bound of size 0'
    reason: PipelineValidationFailed
    status: "False"
    type: Succeeded
  pipelineSpec:
    tasks:
    - name: task-1
      params:
      - name: arrayVal1
        value: []
      taskRef:
        kind: Task
        name: task-with-array-result
    - name: task-2
      params:
      - name: arrayVal1
        value: $(tasks.task-1.results.resultArray)
      taskRef:
        kind: Task
        name: task-with-array-result
  provenance:
    featureFlags:
      AwaitSidecarReadiness: true
      Coschedule: workspaces
      DisableAffinityAssistant: false
      DisableCredsInit: false
      EnableAPIFields: alpha
      EnableCELInWhenExpression: false
      EnableKeepPodOnCancel: false
      EnableProvenanceInStatus: true
      EnableStepActions: false
      EnableTektonOCIBundles: true
      EnforceNonfalsifiability: none
      MaxResultSize: 4096
      RequireGitSSHSecretKnownHosts: false
      ResultExtractionMethod: termination-message
      RunningInEnvWithInjectedSidecars: true
      ScopeWhenExpressionsToTask: false
      SendCloudEventsForRuns: false
      SetSecurityContext: false
      VerificationNoMatchPolicy: ignore
  startTime: "2023-11-18T11:06:31Z"

Steps to Reproduce the Problem

1. Create the above yaml in the cluster.

Additional Info

• Kubernetes version:

  Output of kubectl version:

$ kubectl version
Client Version: v1.28.3
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3
Server Version: v1.27.5

• Tekton Pipeline version:

$ tkn version
Client version: 0.33.0
Pipeline version: v0.53.2

# This issue also exists in Pipeline version: 0.41.x.

I’ve also read the documentation, is this possibly what you anticipated?

• TEP-0076: Expanded array support: results and indexing
• Pipeline Using Results
• Task Emitting Results

[Yongxuanzhang]

/assign

[l-qing]

@Yongxuanzhang It seems that toggling this feature(#6816) does not solve my problem?

I am using Tekton Pipeline v0.53.2 and have modified the feature flag enable-api-fields: alpha, but the problem persists.

[Yongxuanzhang]

@Yongxuanzhang It seems that toggling this feature(#6816) does not solve my problem?

I am using Tekton Pipeline v0.53.2 and have modified the feature flag enable-api-fields: alpha, but the problem persists.

Sorry I was on vocation last week. Will take a look now!

[Yongxuanzhang]

Hi, I think the bug is fixed, please let me know if there are any other issues

[l-qing]

Hi, I think the bug is fixed, please let me know if there are any other issues

Very well, I’ll come back to report if I encounter others. 😆

[Yongxuanzhang]

Hi, I think the bug is fixed, please let me know if there are any other issues

Very well, I’ll come back to report if I encounter others. 😆

Thanks!!