variable substitution in finally section

variables under params section were not substituted with the values for
tasks in finally section. Fixing the parameter interpolation for final tasks.

pkg/reconciler/pipelinerun/resources/apply.go

@@ -93,7 +93,8 @@ func ApplyTaskResults(targets PipelineRunState, resolvedResultRefs ResolvedResul
 func ApplyReplacements(p *v1beta1.PipelineSpec, replacements map[string]string, arrayReplacements map[string][]string) *v1beta1.PipelineSpec {
 	p = p.DeepCopy()
 
-	tasks := p.Tasks
+	// 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)

pkg/reconciler/pipelinerun/resources/apply_test.go

@@ -134,6 +134,27 @@ func TestApplyParameters(t *testing.T) {
 					tb.PipelineTaskParam("first-task-third-param", "static value"),
 					tb.PipelineTaskParam("first-task-fourth-param", "first", "fourth-value", "array"),
 				))),
+	}, {
+		name: "parameter evaluation with 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.FinalPipelineTask("final-task-1", "final-task",
+					tb.PipelineTaskParam("final-task-first-param", "$(params.first-param)"),
+					tb.PipelineTaskParam("final-task-second-param", "$(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.FinalPipelineTask("final-task-1", "final-task",
+					tb.PipelineTaskParam("final-task-first-param", "default-value"),
+					tb.PipelineTaskParam("final-task-second-param", "second-value"),
+				))),
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {