Case-insensitive duplication check in TaskRunSpec's params

[chuangw6]

Background

There is a function named validateNoDuplicateNames in place to check case-insensitive duplication against taskRun spec's params, WorkspaceBindings, StepOverrides and SidecarOverrides.

For params duplication check, it's only used in taskRun spec's params, but not task spec params. To make sure param names are consistent, #4806 will also call this validateNoDuplicateNames to validate names in task spec params.

Expected Behavior

We should expect this function to work correctly regardless of the order of case-insensitive duplications.

Actual Behavior

• If name foo is provided in taskRun spec's params and then Foo, it can check duplication.
• If a name Foo is provided in taskRun spec's params and then foo, it fails to check duplication.

Proposed solution

• caused by the implementation of validateNoDuplicateNames.

Question

Why do we check case-insensitive duplication not case-sensitive? In other words, is there any problem with treating name foo and Foo as two different parameters?

Steps to Reproduce the Problem

apiVersion: tekton.dev/v1beta1
kind: TaskRun
metadata:
  generateName: case-
spec:
  params:
    - name: Foo
      value: "x"
    - name: foo
      value: "y"
  taskSpec:
    params:
      - name: foo
      - name: Foo
    results:
      - name: echo-output
        description: "successful echo"
    steps:
      - name: echo-params
        image: bash
        script: |
          set -e
          echo $(params.foo) | tee $(results.echo-output.path)

1. run the yaml above you can see, it cannot check duplicated Foo and foo in taskrun spec.
2. change the order of Foo and foo in taskrun spec (provide value for foo first and then Foo) and apply again, you can see it validates the duplication

Error from server (BadRequest): error when creating "case-sensitivity.yaml": admission webhook "validation.webhook.pipeline.tekton.dev" denied the request: validation failed: expected exactly one, got both: spec.params[Foo].name

[chuangw6]

/assign