Add validation for condition check name

This will add validation for condition check name like the
one we are doing for task step name

Right now the condition is getting created with
invalid name format but when we use it in pipeline
its not working

pkg/apis/pipeline/v1alpha1/condition_validation.go

@@ -18,9 +18,11 @@ package v1alpha1
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/tektoncd/pipeline/pkg/apis/validate"
 	"k8s.io/apimachinery/pkg/api/equality"
+	"k8s.io/apimachinery/pkg/util/validation"
 	"knative.dev/pkg/apis"
 )
 
@@ -38,6 +40,15 @@ func (cs *ConditionSpec) Validate(ctx context.Context) *apis.FieldError {
 		return apis.ErrMissingField(apis.CurrentField)
 	}
 
+	// Validate condition check name
+	if errs := validation.IsDNS1123Label(cs.Check.Name); cs.Check.Name != "" && len(errs) > 0 {
+		return &apis.FieldError{
+			Message: fmt.Sprintf("invalid value %q", cs.Check.Name),
+			Paths:   []string{"Check.name"},
+			Details: "Condition check name must be a valid DNS Label, For more info refer to https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#names",
+		}
+	}
+
 	if err := validateSteps([]Step{cs.Check}).ViaField("Check"); err != nil {
 		return err
 	}

pkg/apis/pipeline/v1alpha1/condition_validation_test.go

@@ -22,10 +22,9 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
-	"knative.dev/pkg/apis"
-
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1alpha1"
 	tb "github.com/tektoncd/pipeline/test/builder"
+	"knative.dev/pkg/apis"
 )
 
 func TestCondition_Validate(t *testing.T) {
@@ -72,6 +71,18 @@ func TestCondition_Invalidate(t *testing.T) {
 			Message: "step 0 script cannot be used with command",
 			Paths:   []string{"Spec.Check.script"},
 		},
+	}, {
+		name: "condition with invalid check name",
+		cond: tb.Condition("cond",
+			tb.ConditionSpec(
+				tb.ConditionSpecCheck("Cname", "image", tb.Command("exit 0")),
+				tb.ConditionSpecCheckScript("echo foo"),
+			)),
+		expectedError: apis.FieldError{
+			Message: "invalid value \"Cname\"",
+			Paths:   []string{"Spec.Check.name"},
+			Details: "Condition check name must be a valid DNS Label, For more info refer to https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#names",
+		},
 	}}
 
 	for _, tc := range tcs {