Replace ValidateFrom with pipelineSpec.Validate

[dibyom]

Changes

While working on #1256 I noticed that we had two different functions
to validate that the from field. One was being used by the webhook,
and the other in the reconciler. I replaced the ValidateFrom in the
reconciler with the more general Validate that validates the entire
pipeline spec, not just one field. In addition, I fixed some of the
reconciler tests that were now failing due to having an invalid pipeline
spec e.g. pipeline tasks with no name.

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[tekton-robot]

The following is the coverage report on pkg/.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/reconciler/pipelinerun/pipelinerun.go	83.5%	83.9%	0.4
pkg/reconciler/pipelinerun/resources/pipelinerunresolution.go	95.2%	94.6%	-0.6

[ghost]

/lgtm

[vdemeester]

This is the PipelineSpec validateFrom function.

func validateFrom(tasks []PipelineTask) error {
	taskOutputs := map[string][]PipelineTaskOutputResource{}
	for _, task := range tasks {
		var to []PipelineTaskOutputResource
		if task.Resources != nil {
			to = make([]PipelineTaskOutputResource, len(task.Resources.Outputs))
			copy(to, task.Resources.Outputs)
		}
		taskOutputs[task.Name] = to
	}
	for _, t := range tasks {
		if t.Resources != nil {
			for _, rd := range t.Resources.Inputs {
				for _, pb := range rd.From {
					outputs, found := taskOutputs[pb]
					if !found {
						return xerrors.Errorf("expected resource %s to be from task %s, but task %s doesn't exist", rd.Resource, pb, pb)
					}
					if !isOutput(outputs, rd.Resource) {
						return xerrors.Errorf("the resource %s from %s must be an output but is an input", rd.Resource, pb)
					}
				}
			}
		}
	}
	return nil
}

In the PipelineSpec validation, we don't check the sameBinding case 🤔 I am not entirely sure what this check was about but we may be missing something…

[dibyom]

Looking at the test cases for the sameBinding case i.e. the ones that test that the error contains the word ambiguous, there are 3 test cases:

1. from tries to reference input - covered by spec.Validate
2. "from resource doesn't exist" - covered by spec.Validate
3. "from is bound to different resource" - need to double check what this case is doing 🤔

[dibyom]

Ok, so case 3 is from say task B has a from that says use resource "foo" from Task A while Task A produces a resource named "bar". I think pipelineSpec.Validate covers this. So, I think all 3 cases of "same binding" are covered

[vdemeester]

/lgtm

[tekton-robot]

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[vdemeester]

Is there a race (in our tests or code) (see here)

    ---
    apiVersion: tekton.dev/v1alpha1
    kind: Task
    metadata:
      creationTimestamp: "2019-10-26T16:14:32Z"
      generation: 1
      name: status-task
      namespace: arendelle-5n7wl
      resourceVersion: "4775"
      selfLink: /apis/tekton.dev/v1alpha1/namespaces/arendelle-5n7wl/tasks/status-task
      uid: b1c92802-f80b-11e9-a134-42010a800114
    spec:
      steps:
      - args:
        - -c
        - echo hello
        command:
        - /bin/sh
        image: busybox@sha256:895ab622e92e18d6b461d671081757af7dbaa3b00e3e28e12505af7817f73649
        name: hello
        resources: {}
    
    ---
    apiVersion: tekton.dev/v1alpha1
    kind: TaskRun
    metadata:
      creationTimestamp: "2019-10-26T16:14:32Z"
      generation: 1
      name: status-taskrun
      namespace: arendelle-5n7wl
      resourceVersion: "4777"
      selfLink: /apis/tekton.dev/v1alpha1/namespaces/arendelle-5n7wl/taskruns/status-taskrun
      uid: b1cb2bff-f80b-11e9-a134-42010a800114
    spec:
      inputs: {}
      outputs: {}
      podTemplate: {}
      serviceAccountName: ""
      taskRef:
        kind: Task
        name: status-task
      timeout: 1h0m0s
    status:
      conditions:
      - lastTransitionTime: "2019-10-26T16:14:32Z"
        message: 'error when listing tasks for taskRun status-taskrun: task.tekton.dev
          "status-task" not found'
        reason: TaskRunResolutionFailed
        status: "False"
        type: Succeeded
      podName: ""
      startTime: "2019-10-26T16:14:32Z"

[vdemeester]

/test pull-tekton-pipeline-integration-tests

[dibyom]

/test pull-tekton-pipeline-integration-tests

[dibyom]

/test pull-tekton-pipeline-integration-tests

[bobcatfish]

Nice catch @dibyom !! 🎉

@vdemeester should we open an issue about that race? 🏇

[vdemeester]

I guess we should 👼