[StepActions] when using a stepTemplate the ref gets removed

pkg/apis/pipeline/v1/merge.go

@@ -60,7 +60,7 @@ func MergeStepsWithStepTemplate(template *StepTemplate, steps []Step) ([]Step, e
 		amendConflictingContainerFields(&merged, s)
 
 		// Pass through original step Script, for later conversion.
-		newStep := Step{Script: s.Script, OnError: s.OnError, Timeout: s.Timeout, StdoutConfig: s.StdoutConfig, StderrConfig: s.StderrConfig, Results: s.Results, Params: s.Params}
+		newStep := Step{Script: s.Script, OnError: s.OnError, Timeout: s.Timeout, StdoutConfig: s.StdoutConfig, StderrConfig: s.StderrConfig, Results: s.Results, Params: s.Params, Ref: s.Ref}
 		newStep.SetContainerFields(merged)
 		steps[i] = newStep
 	}

pkg/apis/pipeline/v1/merge_test.go

@@ -19,6 +19,8 @@ package v1_test
 import (
 	"testing"
 
+	"k8s.io/utils/pointer"
+
 	"github.com/google/go-cmp/cmp"
 	v1 "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1"
 	"github.com/tektoncd/pipeline/test/diff"
@@ -152,6 +154,36 @@ func TestMergeStepsWithStepTemplate(t *testing.T) {
 				Name: "param",
 			}},
 		}},
+	}, {
+		name: "ref-should-not-be-removed",
+		template: &v1.StepTemplate{
+			SecurityContext: &corev1.SecurityContext{
+				RunAsNonRoot: pointer.Bool(true),
+			},
+		},
+		steps: []v1.Step{{
+			Ref:     &v1.Ref{Name: "my-step-action"},
+			OnError: "foo",
+			Results: []v1.StepResult{{
+				Name: "result",
+			}},
+			Params: v1.Params{{
+				Name: "param",
+			}},
+		}},
+		expected: []v1.Step{{
+			SecurityContext: &corev1.SecurityContext{
+				RunAsNonRoot: pointer.Bool(true),
+			},
+			Ref:     &v1.Ref{Name: "my-step-action"},
+			OnError: "foo",
+			Results: []v1.StepResult{{
+				Name: "result",
+			}},
+			Params: v1.Params{{
+				Name: "param",
+			}},
+		}},
 	}, {
 		name: "merge-env-by-step",
 		template: &v1.StepTemplate{