带有Baum和Laravel Commentable的嵌套集:插入没有Commentable id和类型的子注释

我正在尝试使用Laravel Commentable实现多线程注释，它使用了Baum的嵌套集

我已经设法使根评论工作，但是当我回复评论时，数据库中的记录在没有commentable_id和commentable_type的情况下插入，所以没有办法知道对该评论的回复是否适用于App'Post或App'Product，因为这2个字段是空的，我似乎无法理解为什么。

users: id, name, email...
posts: id, user_id, subreddit_id...
comments: id, user_id, parent_id, lft, rgt, depth, commentable_id, commentable_type

路线

Route::post('comments/{post}', ['as' => 'comment', 'uses' => 'PostsController@createComment']);
Route::post('comments/{comment}/child', ['as' => 'child-comment', 'uses' => 'PostsController@createChildComment']);

PostController中的方法

public function createComment($id) {
    $post = Post::with('user.votes')->with('subreddit.moderators')->where('id', $id)->first();
    $comment = new Comment;
    $comment->body = Input::get('comment');
    $comment->user_id = Auth::id();
    $post->comments()->save($comment);
}
public function createChildComment(Post $post){
    $parent = Comment::find(Input::get('parent_id'));
    $comment = new Comment;
    $comment->body = Input::get('child-comment');
    $comment->user_id = Auth::id();
    $comment->save();
    $comment->makeChildOf($parent);
}

查看根注释和子注释

<-- This is for root comments --/>
{!! Form::open(['route' => ['comment', $post]]) !!}
@foreach($comments as $comment)
@endforeach
{!! Form::close() !!}
<-- This is for children comments --/>
{!! Form::open(['route' => ['child-comment', $comment]]) !!}
<input type="hidden" name="parent_id" value="{{ $comment->id }}"/>
{!! Form::close() !!}