Use kmeta.ChildName to create DNS-safe names.

My recent change uncovered a latent bug where especially long test names result in especially long container names, which fails certain validations.  Unfortunately it slipped in because the test was expected to fail.

This leverages an upstream helper we created to solve ~exactly this problem.  You get DNS-safe short names based on an input name and a suffix, which are deterministic, and are friendly for suitably short inputs.

Fixes: #3393

Author: mattmoor

pkg/reconciler/pipelinerun/resources/conditionresolution.go

@@ -26,6 +26,7 @@ import (
 	"github.com/tektoncd/pipeline/pkg/apis/resource"
 	resourcev1alpha1 "github.com/tektoncd/pipeline/pkg/apis/resource/v1alpha1"
 	corev1 "k8s.io/api/core/v1"
+	"knative.dev/pkg/kmeta"
 )
 
 const (
@@ -96,7 +97,7 @@ func (state TaskConditionCheckState) IsSuccess() bool {
 // ConditionToTaskSpec creates a TaskSpec from a given Condition
 func (rcc *ResolvedConditionCheck) ConditionToTaskSpec() (*v1beta1.TaskSpec, error) {
 	if rcc.Condition.Spec.Check.Name == "" {
-		rcc.Condition.Spec.Check.Name = unnamedCheckNamePrefix + rcc.Condition.Name
+		rcc.Condition.Spec.Check.Name = kmeta.ChildName(unnamedCheckNamePrefix, rcc.Condition.Name)
 	}
 
 	t := &v1beta1.TaskSpec{

pkg/reconciler/pipelinerun/resources/conditionresolution_test.go

@@ -215,6 +215,18 @@ func TestResolvedConditionCheck_ConditionToTaskSpec(t *testing.T) {
 				Image: "ubuntu",
 			}}},
 		},
+	}, {
+		name: "default-container-name",
+		cond: tbv1alpha1.Condition("very-very-very-very-very-very-very-very-very-very-very-long-name", tbv1alpha1.ConditionSpec(
+			tbv1alpha1.ConditionSpecCheck("", "ubuntu"),
+		)),
+		want: v1beta1.TaskSpec{
+			Steps: []v1beta1.Step{{Container: corev1.Container{
+				// from: kmeta.ChildName("condition-check-", "very-very-very-very-very-very-very-very-very-very-very-long-name"),
+				Name:  "condition-check-1305b14e3f3bb99ff83cbb3a68020520very-very-very",
+				Image: "ubuntu",
+			}}},
+		},
 	}, {
 		name: "with-input-params",
 		cond: tbv1alpha1.Condition("bar", tbv1alpha1.ConditionSpec(