Refactor ResolvedPipelineTask and remove redundant fields

Currently, PipelineRun resolution code can be difficult to understand. This commit removes some of the redundant fields in  ResolvedPipelineTask including the singular version of: TaskRun, TaskRunName, ObjectRun, ObjectRunName so that only the list of TaskRuns, TaskRunNames,  ObjectRuns, ObjectRunNames can be used  regardless if the PipelineTask is matrixed or not. This also streamlines the codebase by removing the switch statements used throughout. This partially addresses Issue tektoncd#6628.

pkg/reconciler/pipelinerun/pipelinerun.go

@@ -772,34 +772,21 @@ func (c *Reconciler) runNextSchedulableTask(ctx context.Context, pr *v1beta1.Pip
 			}
 		}()
 
-		switch {
-		case rpt.IsCustomTask() && rpt.PipelineTask.IsMatrixed():
+		if rpt.IsCustomTask() {
 			rpt.RunObjects, err = c.createRunObjects(ctx, rpt, pr)
 			if err != nil {
 				recorder.Eventf(pr, corev1.EventTypeWarning, "RunsCreationFailed", "Failed to create Runs %q: %v", rpt.RunObjectNames, err)
 				err = fmt.Errorf("error creating Runs called %s for PipelineTask %s from PipelineRun %s: %w", rpt.RunObjectNames, rpt.PipelineTask.Name, pr.Name, err)
 				return err
 			}
-		case rpt.IsCustomTask():
-			rpt.RunObject, err = c.createRunObject(ctx, rpt.RunObjectName, nil, rpt, pr)
-			if err != nil {
-				recorder.Eventf(pr, corev1.EventTypeWarning, "RunCreationFailed", "Failed to create Run %q: %v", rpt.RunObjectName, err)
-				err = fmt.Errorf("error creating Run called %s for PipelineTask %s from PipelineRun %s: %w", rpt.RunObjectName, rpt.PipelineTask.Name, pr.Name, err)
-				return err
-			}
-		case rpt.PipelineTask.IsMatrixed():
+		} else {
 			rpt.TaskRuns, err = c.createTaskRuns(ctx, rpt, pr)
 			if err != nil {
-				recorder.Eventf(pr, corev1.EventTypeWarning, "TaskRunsCreationFailed", "Failed to create TaskRuns %q: %v", rpt.TaskRunNames, err)
-				err = fmt.Errorf("error creating TaskRuns called %s for PipelineTask %s from PipelineRun %s: %w", rpt.TaskRunNames, rpt.PipelineTask.Name, pr.Name, err)
-				return err
-			}
-		default:
-			rpt.TaskRun, err = c.createTaskRun(ctx, rpt.TaskRunName, nil, rpt, pr)
-			if err != nil {
-				recorder.Eventf(pr, corev1.EventTypeWarning, "TaskRunCreationFailed", "Failed to create TaskRun %q: %v", rpt.TaskRunName, err)
-				err = fmt.Errorf("error creating TaskRun called %s for PipelineTask %s from PipelineRun %s: %w", rpt.TaskRunName, rpt.PipelineTask.Name, pr.Name, err)
-				return err
+				for i := range rpt.TaskRunNames {
+					recorder.Eventf(pr, corev1.EventTypeWarning, "TaskRunCreationFailed", "Failed to create TaskRun %q: %v", rpt.TaskRunNames[i], err)
+					err = fmt.Errorf("error creating TaskRun called %s for PipelineTask %s from PipelineRun %s: %w", rpt.TaskRunNames[i], rpt.PipelineTask.Name, pr.Name, err)
+					return err
+				}
 			}
 		}
 	}
@@ -820,9 +807,17 @@ func (c *Reconciler) createTaskRuns(ctx context.Context, rpt *resources.Resolved
 	ctx, span := c.tracerProvider.Tracer(TracerName).Start(ctx, "createTaskRuns")
 	defer span.End()
 	var taskRuns []*v1beta1.TaskRun
-	matrixCombinations := rpt.PipelineTask.Matrix.FanOut()
+	var matrixCombinations []v1beta1.Params
+
+	if rpt.PipelineTask.IsMatrixed() {
+		matrixCombinations = rpt.PipelineTask.Matrix.FanOut()
+	}
+
 	for i, taskRunName := range rpt.TaskRunNames {
-		params := matrixCombinations[i]
+		var params v1beta1.Params
+		if len(matrixCombinations) > 0 {
+			params = matrixCombinations[i]
+		}
 		taskRun, err := c.createTaskRun(ctx, taskRunName, params, rpt, pr)
 		if err != nil {
 			return nil, err
@@ -894,9 +889,17 @@ func (c *Reconciler) createRunObjects(ctx context.Context, rpt *resources.Resolv
 	var runObjects []v1beta1.RunObject
 	ctx, span := c.tracerProvider.Tracer(TracerName).Start(ctx, "createRunObjects")
 	defer span.End()
-	matrixCombinations := rpt.PipelineTask.Matrix.FanOut()
+	var matrixCombinations []v1beta1.Params
+
+	if rpt.PipelineTask.IsMatrixed() {
+		matrixCombinations = rpt.PipelineTask.Matrix.FanOut()
+	}
+
 	for i, runObjectName := range rpt.RunObjectNames {
-		params := matrixCombinations[i]
+		var params v1beta1.Params
+		if rpt.PipelineTask.IsMatrixed() {
+			params = matrixCombinations[i]
+		}
 		runObject, err := c.createRunObject(ctx, runObjectName, params, rpt, pr)
 		if err != nil {
 			return nil, err