func removeOldPulumiStacks(projectName string) {
	ctx := context.Background()

	ws, err := auto.NewLocalWorkspace(ctx, auto.Project(workspace.Project{
		Name:    tokens.PackageName(projectName),
		Runtime: workspace.NewProjectRuntimeInfo("go", nil),
	}))
	if err != nil {
		fmt.Println("Failed creating workspace from project name:", projectName)
		fmt.Println(err.Error())
		return
	}

	stacks, err := ws.ListStacks(ctx)
	if err != nil {
		fmt.Println("Failed listing stacks for project:", projectName)
		fmt.Println(err.Error())
		return
	}

	sevenDaysAgo := time.Now().Add(-7 * time.Hour * 24).UTC()
	ignoreStacks := []string{"prod", "build", "stage", "production", "staging"}

	var wg sync.WaitGroup
OUTER:
	for _, stack := range stacks {
		// Do nothing for stacks in our ignoreStacks slice
		// This is just an extra precaution
		for _, s := range ignoreStacks {
			if strings.Contains(stack.Name, s) {
				continue OUTER
			}
		}

		if stack.UpdateInProgress {
			continue
		}

		lastUpdated, err := time.Parse(time.RFC3339, stack.LastUpdate)
		if err != nil {
			fmt.Printf("Error parsing last update time for stack:\n%+v\n", stack)
			fmt.Println(err.Error())
			return
		}

		if lastUpdated.Before(sevenDaysAgo) && (strings.Contains(stack.Name, "ephemeral") || strings.Contains(stack.Name, "test")) {
			wg.Add(1)
			go deleteStack(ctx, stack, ws, &wg)
		}
	}

	wg.Wait()
}

func deleteStack(ctx context.Context, stack auto.StackSummary, ws auto.Workspace, wg *sync.WaitGroup) {
	defer wg.Done()
	fmt.Println("Deleting stack:", stack.Name)

	s, err := auto.SelectStack(ctx, stack.Name, ws)
	if err != nil {
		fmt.Printf("Error selecting stack:\n%+v\n", stack)
		fmt.Println(err.Error())
		return
	}

	_, err = s.Destroy(ctx)
	if err != nil {
		fmt.Printf("Error destroying stack:\n%+v\n", stack)
		fmt.Println(err.Error())
		return
	}

	err = ws.RemoveStack(ctx, stack.Name)
	if err != nil {
		fmt.Printf("Failed removing stack:\n%+v\n", stack)
		fmt.Println(err.Error())
		return
	}
	fmt.Println("Removed stack:", stack.Name)
}

go

▶ pulumi version  
v3.0.0

pending_operations

pulumi destroy

pulumi stack rm

pulumi destroy -s my stack

pending_operations

3.1

3.0

stack.Export()

stack.Import()

FROM scratch