Apply replacements in tasks and finally tasks separately

Previously, we created a slice containing both tasks and finally tasks
then applied replacements across all of them. However, the variable
replacements we make in conditions and when expressions in tasks
don't apply to finally tasks. Moreover, this joined slice caused strange
memory allocation side effects when finally tasks were present vs when
they were missing.

pkg/reconciler/pipelinerun/resources/apply.go

@@ -88,16 +88,17 @@ func ApplyTaskResults(targets PipelineRunState, resolvedResultRefs ResolvedResul
 func ApplyReplacements(p *v1beta1.PipelineSpec, replacements map[string]string, arrayReplacements map[string][]string) *v1beta1.PipelineSpec {
 	p = p.DeepCopy()
 
-	// replace param values for both DAG and final tasks
-	tasks := append(p.Tasks, p.Finally...)
-
-	for i := range tasks {
-		tasks[i].Params = replaceParamValues(tasks[i].Params, replacements, arrayReplacements)
-		for j := range tasks[i].Conditions {
-			c := tasks[i].Conditions[j]
+	for i := range p.Tasks {
+		p.Tasks[i].Params = replaceParamValues(p.Tasks[i].Params, replacements, arrayReplacements)
+		for j := range p.Tasks[i].Conditions {
+			c := p.Tasks[i].Conditions[j]
 			c.Params = replaceParamValues(c.Params, replacements, arrayReplacements)
 		}
-		tasks[i].WhenExpressions = tasks[i].WhenExpressions.ReplaceWhenExpressionsVariables(replacements)
+		p.Tasks[i].WhenExpressions = p.Tasks[i].WhenExpressions.ReplaceWhenExpressionsVariables(replacements)
+	}
+
+	for i := range p.Finally {
+		p.Finally[i].Params = replaceParamValues(p.Finally[i].Params, replacements, arrayReplacements)
 	}
 
 	return p

pkg/reconciler/pipelinerun/resources/apply_test.go

@@ -174,6 +174,35 @@ func TestApplyParameters(t *testing.T) {
 					tb.PipelineTaskParam("final-task-first-param", "default-value"),
 					tb.PipelineTaskParam("final-task-second-param", "second-value"),
 				))),
+	}, {
+		name: "parameter evaluation with both tasks and final tasks",
+		original: tb.Pipeline("test-pipeline",
+			tb.PipelineSpec(
+				tb.PipelineParamSpec("first-param", v1beta1.ParamTypeString, tb.ParamSpecDefault("default-value")),
+				tb.PipelineParamSpec("second-param", v1beta1.ParamTypeString),
+				tb.PipelineTask("first-task-1", "first-task",
+					tb.PipelineTaskParam("first-task-first-param", "$(params.first-param)"),
+				),
+				tb.PipelineTask("first-task-2", "first-task",
+					tb.PipelineTaskWhenExpression("$(params.first-param)", selection.In, []string{"$(params.second-param)"})),
+				tb.FinalPipelineTask("final-task-1", "final-task",
+					tb.PipelineTaskParam("final-task-second-param", "$(params.second-param)"),
+				))),
+		run: tb.PipelineRun("test-pipeline-run",
+			tb.PipelineRunSpec("test-pipeline",
+				tb.PipelineRunParam("second-param", "second-value"))),
+		expected: tb.Pipeline("test-pipeline",
+			tb.PipelineSpec(
+				tb.PipelineParamSpec("first-param", v1beta1.ParamTypeString, tb.ParamSpecDefault("default-value")),
+				tb.PipelineParamSpec("second-param", v1beta1.ParamTypeString),
+				tb.PipelineTask("first-task-1", "first-task",
+					tb.PipelineTaskParam("first-task-first-param", "default-value"),
+				),
+				tb.PipelineTask("first-task-2", "first-task",
+					tb.PipelineTaskWhenExpression("default-value", selection.In, []string{"second-value"})),
+				tb.FinalPipelineTask("final-task-1", "final-task",
+					tb.PipelineTaskParam("final-task-second-param", "second-value"),
+				))),
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {